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Fermentation 2018, 4(3), 52; doi:10.3390/fermentation4030052
Enzymes for Wine Fermentation: Current and Perspective Applications
Institute of Molecular Physiology, Microbiology and Wine Research, Johannes Gutenberg-University, 55099 Mainz, Germany
Faculty of Technology, University “Goce Delčev” Štip, Krste Misirkov No. 10-A, P.O. Box 201, 2000 Štip, Macedonia
Author to whom correspondence should be addressed.
Received: 16 May 2018 / Accepted: 5 July 2018 / Published: 9 July 2018
Enzymes are used in modern wine technology for various biotransformation reactions from prefermentation through fermentation, post-fermentation and wine aging. Industrial enzymes offer quantitative benefits (increased juice yields), qualitative benefits (improved color extraction and flavor enhancement) and processing advantages (shorter maceration, settling and filtration time). This study gives an overview about key enzymes used in winemaking and the effects of commercial enzyme preparations on process engineering and the quality of the final product. In addition, we highlight on the presence and perspectives of beneficial enzymes in wine-related yeasts and lactic acid bacteria.
Keywords:wine clarification; extraction; pectinase; glycosidase; protease; phenoloxidase; color; aroma; non-Saccharomyces yeasts
Over the last decades, commercial enzyme preparations have gained increasing popularity in the wine industry [1,2,3,4,5]. They offer many advantages such as accelerated settling and clarification processes, increased juice yield, and improved color extraction (Table 1).
Technical enzyme preparations are usually obtained from fungi, which are cultured under optimal conditions on substrates to facilitate their preparation and purification. In contrast to grape-derived enzymes, which are often inactive under wine conditions (low pH, presence of ethanol, phenolic compounds, sulphite etc.), fungal enzymes are resistant. The production of oenological enzymes for use in the European Union is regulated by the International Organization of Vine and Wine (OIV), which has ruled that Aspergillus niger and Trichoderma sp. may be used as source organisms (i.e., have GRAS, “generally regarded as safe” status) [1,2]. Selected strains from A. niger are fermented under aerobic conditions in optimized growth media for production of pectinases, hemicellulases and glycosidases, Trichoderma species are used for production of glucanases and Lactobacillus fermentum for urease.
Current commercial enzyme preparations are usually cocktails of different activities, such as glucosidases, glucanases, pectinases and proteases . The search for enzymes with improved and more specific characteristics will continue. In this respect, the study and exploration of the high endogenous enzyme potential of wine and grape-associated microorganisms (Table 2) will assist the wine industry to meet prospective technical and consumer challenges. In contrast to filamentous fungi, yeasts with beneficial enzymatic endowment, could be directly used as starter cultures, without application of enzyme preparations.
In the following paragraphs we give an overview on widely used enzyme preparations for wine fermentation and a special focus on wine-associated microorganisms as alternative enzyme sources.
The grape cell wall consists of cellulose microfibrils linked together by a matrix of xyloglucan, mannan, xylan (hemicellulose) and pectin, all of which is stabilized by a protein network. The high viscosity of pectin, which is dissolved after berry crushing impedes juice extraction, clarification and filtration. In addition, pectin prevents diffusion of phenolic and aroma compounds into the must during wine fermentation.
2.1. Commercial Pectinases
The complete degradation of pectin needs cooperation of several enzymes to break the complex molecule into small fragments [1,2]. They include different enzymatic activities:
- Polygalacturonase (homogalacturonan-hydrolase) (PG): hydrolytic depolymerization of the polygalacturonic acid chain. One can differentiate enzymes that cleave either single galacturonic acid units from the chain end (exo-activity, exoPG, EC 18.104.22.168), or in the middle of the chain (endo-activity, endoPG, EC 22.214.171.124).
- Pectinlyase/pectate lyase (EC 126.96.36.199 and 188.8.131.52): nonhydrolytic cleavage of the polygalacturonic acid chain.
- Pectinesterase (EC 184.108.40.206): hydrolytic cleavage of methanol from the d-galacturonic acid chain, causing drastic viscosity reduction in the liquid portion of the mash and better must flow.
- Acetylesterase (EC 220.127.116.11): cleaves acetyl residues from d-galacturonic acid with release of acetic acid. By this way the interfering acetyl residues at the connecting points of the side chains of the “hairy regions” are removed which facilitates further enzymatic degradation.
Most commercial preparations are derived from fungal sources [1,2,3,4,5] and are more or less well-defined enzyme mixtures (Table 3). The application of bulk enzyme preparations is advantageous as it fulfills several functions. Examples are liquefaction enzymes, which contain cellulases and hemicellulases in addition to pectinases.
Commercially available pectinase preparations contain the active enzymes (2–5%) and additives (sugars, inorganic salts, preservatives) which stabilize and standardize the specificities of the products . Factors that generally inhibit proteins will reduce effectiveness of the enzymes. These include juice clarification with bentonite, which adsorbs and deposits the proteins. Alcohol levels above 17% (v/v) and SO2 levels above 500 mg/L inhibit pectinases . Tannin-rich wines show reduced enzyme activity as phenolic polymers react with the proteins and render them useless.
2.1.1. Effect on Juice Extraction, Clarification and Filtration
The pulp of the grape varieties is rich in pectin compounds. The incomplete hydrolysis of these molecules by the endogenous enzymes can therefore cause problems in processing. If pectinases are applied to the pulp prior to pressing, they can improve juice and color yield. For the clarification of musts after pressing, pectinase-based enzyme preparations are recommended. Its pectin methyl esterase and endogalacturonic activities cause hydrolysis of the pectin chains and facilitate the drainage of juice from the pomace with an increased yield of a free-flowing juice with lower viscosity [6,7,8]. In addition, it causes cloud particles to aggregate into larger units that deposit as sediment. The acceleration of the clarification process also produces more compact lees. When applied to the pulp before pressing, it increases juice yield and color yield [6,7,8].
2.1.2. Effect on Color Extraction
Anthocyanidins are the red grape pigments, which mainly occur in the grape skin . The chemical structure, commonly referred to as “flavylium cation”, is characterized by two benzene rings linked by an unsaturated cationic heterocycle. Normally, the dye molecule is linked to a glucose monomer, which improves water solubility and stability. Pelargondin, cyanidin, delphinidin, peonidin, petundin and malvidin are the main variants identified in grapes and wine.
Flavonols are light yellow pigments found in the skins of both red and white grapes . These are mainly the glycosylated forms of kaempferol, quercetin and myricetin. In red wine concentrations are in the range of 100 mg/L, in white wines 1–3 mg/L.
Under natural conditions, solubilization of phenolic compounds from grapes is facilitated by increased ethanol concentrations in the course of alcoholic fermentation. However, the extraction is uncomplete as the grape skin forms a physical barrier against the diffusion of anthocyanins, tannins and flavors from the cells. Therefore, various oenological techniques have been developed that result in wines that have good visual characteristics and are as stable as possible . Especially wines made by pectinase treatment showed higher concentrations of anthocyanins and total phenols, as well as greater color intensity and optical clarity compared to untreated control wines [6,7,8].
Immobilization is a commonly used strategy to conserve the desirable properties of enzymes for biotechnological applications. In addition to improved stability, immobilization offers a number of advantages, such as reusability, ease of product separation, and better control of catalysis. Various methods have been described for the immobilization of pectinases, such as inclusion in alginate , physical adsorption to anionic resins , and covalent bonding to supports such as porous glass  and nylon . A pectinase from Aspergillus niger immobilized on chitosan-coated carriers retained 100% of its original activity after several cycles of reuse .
2.2. Yeast Pectinases
S. cerevisiae strains, despite their genetic ability to secrete an endo-polygalacturonase, usually show no or only weak pectinase activity. In contrast, many so-called “wild” yeasts have been identified to be pectinase producers [16,17,18,19,20].
Grape fermentations at low temperatures (15–20 °C) are believed to protect the volatile compounds, thereby improving the aromatic profile of the wines. Therefore, cold-active enzymes are required for both extraction and clarification . Psychrophilic yeasts are natural sources for such biocatalysts . The pectinolytic enzymes of Cystofilobasidium capitatum and Rhodotorula mucilaginosa are effective under oenological pH (3.5) and temperature conditions (6.0 °C and 12 °C). Also, pectinases from several A. pullulans strains remain active at wine-relevant concentrations of glucose, ethanol or SO2, bearing the potential as processing aids for low-temperature wine fermentations .
Lipids in wine originate directly from the grape berry  and by autolysis of wine yeast . It has been reported that lipid composition undergoes considerable changes during wine fermentation .
Authentic lipases (E.C. 18.104.22.168) are mainly active at the oil–water interface of emulsified substrates with long fatty acid chains. Triglycerides are cleaved rendering glycerol and fatty acids. In contrast, carboxylic ester hydrolases (see below) hydrolyze soluble esters with relatively short fatty acid chains . However, the transition between both activities appears somewhat fluid.
Lipolytic activities have been detected only in few wine-relevant Lactobacillus strains , but in different genera of yeasts isolated from natural environments [29,30]. In theory, lipases could be used for winemaking for decomposition of lipoid cell membranes, thereby improving color extraction from red grape berries (Figure 1).
4.1. Commercial Glucanases
Polysaccharides in must and wine originate from the grape berries (cellulose, hemicellulose, pectins) and from cell walls of yeasts during growth and autolysis (beta-glucans, chitin). Several strains of lactic acid bacteria (especially Pediococcus spp.) and the grape fungus Botrytis cinerea produce viscous capsular or extracellular polysaccharides impairing wine filtration . The colloidal polysaccharides cannot be removed from wine by flocculants, adsorbents or filtration. Thus, commercial products with glucanase activities e.g., those from Trichoderma sp., and Taleromyces versatilis are useful to reduce viscosity of musts and wine caused by microbial contaminations  (Table 3).
Two types of glucanases are relevant for wine fermentation: (i) exo-β-1,3-glucanases split β-glucan chains by sequentially cleaving glucose residues from the non-reducing end and releasing glucose as the sole hydrolysis product and, (ii) endo-β-1,3-glucanases catalyse the intramolecular hydrolysis of β-glucans with release of oligosaccharides.
Some yeast cell constituents, in particular the wall, can exert a significant impact on the technological and sensory properties of wine. The cell wall consists of β-glucans (~60%), mannoproteins (~40%) and chitin (~2%). In particular, the mannoprotein fraction has attracted increasing interest in wine fermentation to stabilize tartaric acid and protein, improve mouthfeel and reduce astringency [32,33,34]. The use of mannoproteins of the cell wall and chitin as binding elements for the removal of undesirable compounds such as ochratoxin A and toxic heavy metals has been proposed. The mannoprotein fractions present in the yeast cell walls are highly variable between species and even strains, providing opportunities for the development of alternative fining products that could replace conventional proteinaceous animal preparations with allergenic potential.
4.2. Microbial Glucanases
A major microbial source of polysaccharide-degrading exoenzymes are non-Saccharomyces yeasts belonging to the genera Kloeckera, Candida, Debaryomyces, Rhodotorula, Pichia, Zygosaccharomyces, Hanseniapora, Kluyveromyces and Wickerhamomyces (Table 4). Glucanolytic enzyme activities were also detected in wine-relevant lactic acid bacteria  (Table 2).
The organoleptic properties of wine are determined by a variety of different compounds that are already present in the grape (aroma) or arise during fermentation or storage (bouquet). Acids such as tartaric acid or citric acid affect the taste, but the characteristic odor and taste is mainly due to volatile organic substances such as esters, alcohols, thiols or terpenes [36,37,38].
Due to their low odor threshold, particularly terpenes determine wine flavor. Like other aroma active compounds (C13 norisoprenoids, benzene derivatives, aliphatic alcohols, phenols), they are secondary metabolites mainly derived from the grape skin. Approximately 90% of these compounds do not exist in a free form, but are conjugated to mono- or disaccharides, thereby forming water-soluble and odourless complexes. The most frequently occurring aroma precursors in grape varieties such as Muscat and Riesling are the glycosidic bound terpenes linalool, nerol and geraniol. The sugar residues consist of rutinoside (rhamnose-glucose), arabinoside (arabinose-glucose) or apioside (apiose-glucose) .
Enzymatic hydrolysis of sugar-conjugated precursors release very aromatic, volatile terpenes (aglycones). Usually, the terminal sugars are first cleaved off by a rhamnosidase, an arabinosidase or an apiosidase. In a second step, the terpenes are released by a β-d-glucopyranosidase. This means that the latter activity alone can release only terpene compounds bound to a single glucose residue. In addition to a stepwise reaction, some glucosidases are able to hydrolyze the glycosidic bond to the aglycone, regardless of the number of sugar residues [39,40]. Nowadays commercial enzyme preparations are available that can hydrolyze the disaccharide directly from the terpene in a single step . In many bulk enzyme preparations, glycosidase activities occur as side activities along with pectinase and glucanase activities (Table 3).
An important microbial source of wine-related enzymatic activities are lactic acid bacteria  (Table 2). Perez-Martin et al.  studied >1000 isolates for glycosidases. The β-glucosidase activities were only found in cells, but not in the supernatants of the cultures. Four O. oeni isolates retained their enzymatic activity under the conditions of winemaking. In a similar study, cell-bound glucosidase and arabinosidase activities from O. oeni strains released high levels of monoterpenes from natural substrates under optimal conditions . The enzymes showed broad substrate specificities (release of both primary and tertiary terpene alcohols) and remained active in grape juice.
Glycosidase activities have been also detected in various non-Saccharomyces yeasts (Candida, Hanseniaspora, Pichia, Metschnikowia, Rhodotorula, Trichosporon, Wickerhamomyces) [43,44,45,46,47,48,49,50,51,52] (Table 5). Several experiments on the technical application of yeast glycosidases to improve organoleptic quality of wines gave positive results [40,44,46,49,50].
Polyphenols in red wine, such as resveratrol, have gained increasing public and scientific interest due to their supposed beneficial effects on human health . A majority of the polyphenols in nature are conjugated to sugars or organic acids, making them more hydrophilic and less bioavailable to humans. The amount of glycosylated forms of resveratrol, known as piceid or polydatin, has been found to be up to ten times higher in red wines. Since these modified forms are less bioactive, experiments with β-glucosidases from various fungal sources have been undertaken to increase the trans-resveratrol content in wines by hydrolysis of glycosylated precursors. The multifunctional glucanase WaExg2 of W. anomalus AS1 released the aglycones from the model compounds arbutin, salicin, esculin and polydatin . WaExg2 was active under typical wine conditions such as low pH (3.5–4.0), high sugar concentrations (up to 20% w/v), high ethanol concentrations (10–15% v/v), presence of sulphites and various cations. Therefore, this yeast strain could be useful in wine production for several purposes: to increase the levels of sensory and beneficial compounds by cleaving glycosylated precursors or reducing the viscosity by hydrolysis of glycan slurries. In this context Madrigal et al.  underlined that glucose- and ethanol-tolerant enzymes from Wickerhamomyces are of great interest to the wine industry.
6. Esterhydrolases and -Synthetases
Esters (e.g., ethyl acetate, isoamyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate) contribute to the most desirable fruity wine flavors [36,37]. They are synthesized by the grapes but are also produced by yeasts in course of alcoholic fermentation . During malolactic fermentation, significant changes in the concentration of individual esters were observed . Presence of alcohol acyltransferases (ester synthesis) and esterases (ester hydrolysis) in wine yeasts  and lactic acid bacteria  is well documented.
Depsides are esters of aromatic hydroxycarboxylic- or phenolic acids with each other or with other carboxylic acids of the grape, such as tartaric acid . These compounds can be hydrolyzed by cinnamoyl esterases (“depsidases”), which often appear as side activities in enzyme preparations made from A. niger  The fission products can have a negative influence on wine quality. Enzymatic deliberated phenolcarboxylic acids, such as caffeic acid or coumaric acid, can be converted by the yeast metabolism to the volatile phenol derivatives 4-vinylguajacol and 4-vinylphenol, which are unpleasant side-tastes in the wine . Therefore, commercial pectinase preparations should be free of depsidase side activities. In a recent study of 15 commercial enzyme preparations, approximately half of the samples yielded significant cinnamoyl esterase activities .
Proteins in must in wine are derived from the grapes, and from microbial cells (yeasts, lactic, acid bacteria) and their activities . Another important source are protein-based wine additives (e.g., lysozyme, ovalbumin, gelatin, casein) which could pose allergenic-like reactions to consumers [60,61,62]. Most of these proteins have vanished after termination of wine fermentation and subsequent fining procedures. However so-called pathogen-related (PR) proteins (β-glucanases, chitinases, thaumatin-related proteins) can still be present. They are synthesized by the plants for defence against bacterial or fungal infections and in response to abiotic stress . Due to their compact structures, they are resistant against acid wine conditions, heat, and proteolysis .
In combination with other wine ingredients, PR proteins can cause undesirable turbidity especially during cold storage of white wines with negative economic consequences . Currently, protein removal is mainly achieved by bentonite addition , a process that can be associated with decreased wine quantity and quality. Bentonite acts essentially as a cation exchanger, and individual wine proteins adsorb to different degrees on the clay . Proteins that are negatively charged at wine pH (about 3.5) and/or are highly glycosylated as laccases of Botrytis cinerea are less bound by bentonite. Thus, new fining agents are desired to remove proteins from wine.
7.1. Proteases from Fungal and Plant Sources
Enzymatic degradation of wine proteins seems an attractive alternative to bentonite treatment as it would minimize losses of volume and aroma. As a prerequisite, suitable proteases have to be active under specific wine conditions (acid pH, presence of ethanol, sulphites, phenolics) and preferably act at low temperatures. Another challenge is the resistance of PR proteins against proteolysis due to their special molecular features like disulfide-bonds and glycosylations. Nevertheless, other grape proteins might be more susceptible, and thus proteases may help to reduce effective bentonite dosages. Currently, proteases from plants (papain, bromelain) have been tested with some promising results [65,66]. A fungal protease from Aspergillus sp. (aspergilloglutamic peptidase) has already approved for Australian winemaking . The enzymatic procedure involves flash-pasteurization of grape must and is thus limited to specialized wineries. In this context, a protease of Botrytis cinerea BcAp8 has been described to hydrolyze grape chitinase at moderate temperatures .
7.2. Microbial Proteases
Microbial proteases can be an alternative or supplement to bentonite treatment for removal of unwanted wine proteins. Most Saccharomyces cerevisiae strains show no extracellular protease activity on diagnostic agar media [16,17,18,19,69]. However, a 72 kDa extracellular pepsin-like aspartic protease was characterized from a PIR 1 strain [70,71]. The enzyme was active during grape juice fermentations, although it did not affect turbidity-inducing proteins, unless the wine was incubated at 38 °C for extended time.
Proteinase A (PrA, saccharomycin; EC 22.214.171.124) is the major vacuole protease of S. cerevisiae encoded by the PEP4 gene. As result of yeast autolysis, PrA enters wine in course of alcoholic fermentation. Far more, it has been found that under stress conditions (e.g., nutrient limitations) PrA is not targeted to the vacuole, but is misdirected to the cell membrane and secreted in the medium . This would be advantageous for winemaking in view of haze reduction. Interestingly, the same situation is undesirable for beer brewery as PrA degrades proteins (e.g., lipid transfer protein 1), necessary for foam formation. Apart from PrA, S. cerevisiae expresses different cell-bound proteases, some of which are not fully characterized .
Non-Saccharomyces yeasts are important sources of extracellular enzymes including proteases (Table 6). Strains of Metschnikowia pulcherrima and Wickerhamomyces anomalus secreted aspartic proteases and degraded a model protein (bovine serum albumin) during growth in grape juice . In a recent study, heterologous expressed aspartic protease MpAPr1 from M. pulcherrima  was added to a Sauvignon Blanc must. It was shown that the enzyme was active during fermentation and degraded wine proteins to some extent . An alternative strategy would be to perform wine fermentations with appropriate protease-positive starter cultures. In addition to cost reductions, there are no administrative restrictions for yeast applications in must and wine, which must be taken into account with enzyme preparations.
Occurrence of proteolytic activities in lactic acid bacteria is also well-documented  (Table 2). Growth of Oenococcus oeni depends on the presence of amino acids in the culture medium because of deficiency in corresponding synthetic pathways. This bacterium secretes several proteases which may help to gain access to rare nitrogen sources during malolactic fermentation .
Spontaneous and enzymatic oxidations exert dramatic effects on the final phenolic composition from the grape berry to bottled wine [82,83]. Once the integrity of the berries is destroyed, oxidative enzymes (phenoloxidases) and their phenolic substrates are exposed to the air, resulting in enzymatic browning (Figure 2).
There are two classes of copper enzymes responsible for these reactions [82,83]: Tyrosinase (E.C. 126.96.36.199) hydroxylates monophenols to ortho-diphenols and oxidizes the latter to ortho-quinone intermediates which easily react further to polymeric, mostly colored products. Laccase (E.C. 188.8.131.52) has no monohydroxylase activity, and oxidizes a broad spectrum of different phenols and other compounds by a radical mechanism. Tyrosinase originates from grape berries , whereas laccases in must and wine are derived from epiphytic fungi, particularly Botrytis cinerea . Phenolic compounds as caffeic acid, gallic acid, vanillic acid, ferulic acid, or especially resveratrol are known for their beneficial effects on human health. In addition to be radical scavengers, they are activators of the human’s intrinsic cellular antioxidant system and have antimicrobial properties. Tyrosinase and laccase oxidize phenolic wine compounds and thus alter their antioxidant and antimicrobial properties [85,86,87]. In this context, it is an interesting observation that gallic acid oxidation by a laccase from Trametes versicolor was higher at 30 °C than at 45 °C. Although fungal laccases are usually more active at higher temperatures, the effect can be explained by reduced oxygen solubility under the experimental conditions .
Laccase is generally not very welcome in wine, but several studies have ruled out that controlled laccase treatments could promote wine stabilization and even improve sensory properties [89,90,91,92,93].
Volatile phenols particular produced by Brettanomyces/Dekkera sp. yeasts are associated with a serious “Brett” taste defect in wine. Lustrata et al.  used a laccase from T. versicolor to reduce concentrations of 4-ethylguaiacol and 4-ethylphenol in a synthetic model wine.
Biogenic amines (BA) are another class of undesirable compounds in wine [95,96,97]. They originate from the grape berries or are formed during fermentation by activities of decarboxylase-positive microorganisms [98,99,100,101,102]. Although more common in foods such as cheese, BA have received much attention in wine, as ethanol can enhance the negative effects on human health by inhibiting the enzymes responsible for the detoxification of these compounds .
Enzymatic degradation of BA is usually catalyzed by various classes of oxidases [103,104]. Depending on the type of prosthetic group, they can be classified into FAD-dependent (E.C. 184.108.40.206) and copper-containing amine oxidases (CAOs, E.C. 220.127.116.11). The latter have been detected in various yeasts such as Kluyeromyces marxianus or Debaryomyces hansenii [105,106]. These enzymes belong to the class of type 2 or “non-blue” copper proteins which convert primary amines to the corresponding aldehydes with an equimolar consumption of molecular oxygen and formation of hydrogen peroxide and ammonia.
Aromatic amines such as tyramine, phenylethylamine, tryptamine or serotonin are another class of compounds that can be oxidized by laccases . Callejónet et al.  detected enzymatic activities responsible for BA degradation in lactic acid bacterial strains isolated from wine. Responsible enzymes have been isolated and purified from Lactobacillus plantarum J16 and Pediococcus acidilactici CECT 5930 strains and have been identified as intracellular laccase-like multicopper oxidases. When the L. plantarum J16 laccase was overexpressed in Escherichia coli, it oxidized some BA, mainly tyramine .
Increased amounts of urea in wine can originate from yeast activities and then converted by a chemical reaction into the carcinogenic substance urethane (ethylcarbamate). During malolactic fermentation, lactic acid bacteria can produce other precursors of ethyl carbamate, such as arginine-derived citrulline and carbamyl phosphate. Especially at higher temperatures fermented wines may contain excessive amounts of urethane . Therefore appropriate precautions should be taken to prevent the production of urethane. These include, for example, the selection of suitable starter cultures for malolactic fermentations and the reduction of arginine concentrations in the grape. Urease was introduced in 1997 by the EU as a new enzymatic wine treatment agent and can be used in exceptional cases. The enzyme splits urea into ammonia and carbon dioxide, preventing urethane formation. The commercial urease from Lactobacillus fermentum is effective on urea at doses of 50 mg/L in red wines and 25 mg/L in white wines .
Yeasts, lactic acid and acetic acid bacteria have a significant influence on wine quality . Microbial growth in musts and wines is conventionally controlled by the addition of sulfur dioxide. However, presence of sulphites in alcoholic beverages, particularly in wines, can cause pseudo-allergic responses with symptoms ranging from gastrointestinal problems to anaphylactic shock [32,33]. Other antimicrobials such as sorbic acid and dimethyl carbonate are primarily active against yeasts, but have limited activity against bacteria [32,34].
Lysozyme (EC 18.104.22.168) is a muramidase widely used to control microbial growth in foods such as cheese and wines [111,112]. Extensive enzymatic hydrolysis of the bacterial cell wall peptidoglycan, a polymer of N-acetyl-d-glucosamine units which are β-1,4-linked to N-acetylmuramic acid, results in cell lysis and death in hypoosmotic environments. Some lysozymes can kill bacteria by stimulating autolysin activity. In addition, bactericidal mechanisms involving membrane damage without enzymatic hydrolysis of peptidoglycan has been reported for c-type lysozymes, such as hen egg white lysozyme . Gram-negative bacteria (i.e., acetic acid bacteria) are rather resistant against lysozyme, because the outer membrane acts as a barrier.
Lysozyme commercially produced from hen’s egg white has been approved for winemaking by the International Organization of Vine and Wine in 2001 . The amount added normally ranges between 250–500 mg/L. Four main applications and dosages are: (a) prevention of the onset of malolactic fermentation (early addition of 100–150 mg/L); (b) total inhibition of bacteria activity and malolactic fermentation (500 mg/L); (c) protection of wine during suboptimal alcoholic fermentation (250–300 mg/L); (d) stabilization of wine after malolactic fermentation (250–300 mg/L). Lysozyme can be eliminated by addition of fining agents, among which bentonite and metatartaric acid are the most efficient.
It has been reported that various Gram-positive strains of Pediococcus sp., Lactobacillus sp. and Oenococcus oeni  were not efficiently hydrolyzed by hen’s egg white lysozyme. Reasonable explanations are structural modifications of the peptidoglycan, like N-deacetylation and O-acetylation of the glycan chains or amidation of free carboxyl groups of amino acids in the peptide chains . As a possible alternative to hen’s egg white lysozyme, exoenzymes (protease and muramidase) from Streptomyces species showed a broad bacteriolytic spectrum under winemaking conditions [98,113].
It should be mentioned that hen’s egg lysozyme can display pH-dependent chitinase side activities. Under adverse conditions yeast cell walls (containing 2–4% chitin primarily in the bud scar regions) can be weakened by lysozyme with significant effects on vitality and stress response of Saccharomyces cerevisiae during wine fermentation .
11. Legislative Regulations
The use of enzymes in wine production in the European Union is regulated by the International Organisation of Vine and Wine (OIV). Specified resolutions define general aspects of enzymes in winemaking, the permitted enzyme activities, mode of application and enzyme activity measurements. The USA, Canada and China have national regulations in winemaking .
Genetic engineering. Today’s enzyme production is based either on special selected wildtype strains or on genetically modified organisms (GMOs). The use of GMO production strains has considerable advantages: the product yields with GMOs is much higher than with wild strains and undesirable side activities become minimized. This makes it more efficient to produce and to guarantee the purity of the enzyme products. The labelling is regulated by the resolution OIV-OENO 485-2012.
GMOs for must fermentations. Although increasing numbers of Saccharomyces yeasts have been improved by genetically engineering [115,116], only two GMOs have been allowed for winemaking in three countries. The first recombinant strain to get official approval by appropriate food safety authorities (in the USA and Canada) was the malolactic wine yeast ML01. The GMO carries the Schizosaccharomyces pombe malate permease gene (mae1) and the Oenococcus oeni malolactic gene (mleA). The second strain ECMo01 expresses the urease gene constitutively to prevent formation of urethane . Whether yeast strains obtained by protoplast fusion should be considered as GMO is in legal limbo.
Nowadays, the use of technical enzymes is a well-established strategy to improve wine quantity and quality. Currently they are mainly produced by Aspergillus species and applied as bulk preparations with several side activities. In view of consumer safety, more defined activities and alternative biological producers seem to be preferable. Yeasts, naturally occurring on grapes, have been found to be a rich source of oenological interesting enzymes. Their activities can be exploited in form of new enzyme products or directly as starter cultures for wine fermentation. This would satisfy the increasing trend to produce more individual wines with the aid of non-Saccharomyces yeasts .
Conflicts of Interest
The authors declare no conflict of interest.
- Mojsov, K. Use of enzymes in wine making: A review. Int. J. Market. Technol. 2013, 3, 112–127. [Google Scholar]
- Mojsov, K.; Andronikov, D.; Janevski, A.; Jordeva, S.; Zezova, S. Enzymes and wine—The enhanced quality and yield. Adv. Technol. 2015, 4, 94–100. [Google Scholar] [CrossRef]
- Ugliano, M. Enzymes in winemaking. In Wine Chemistry and Biochemistry; Morena-Arribas, M.V., Polo, M.C., Eds.; Springer: New York, NY, USA, 2009; pp. 103–126. [Google Scholar]
- Van Rensburg, P.; Pretorius, I.S. Enzymes in winemaking: Harnessing natural catalysts for efficient biotransformations: A review. S. Afr. J. Enol. Vitic. 2000, 21, 52–73. [Google Scholar]
- Hüfner, E.; Haßelbeck, G. Application of microbial enzymes during winemaking. In Biology of Microorganisms on Grapes, in Must and in Wine, 2nd ed.; König, H., Unden, G., Fröhlich, J., Eds.; Springer International Publishing: Cham, Switzerland, 2017; pp. 635–658. [Google Scholar]
- Mojsov, K.; Ziberoski, J.; Bozinovic, Z. The effect of pectolytic enzyme treatments on red grapes mash of Vranec on grape juice yields. Perspect. Innov. Econ. Bus. 2011, 7, 84–86. [Google Scholar] [CrossRef]
- Mojsov, K.; Ziberoski, J.; Bozinovic, Z.; Petreska, M. A comparison of effects of three commercial pectolytic enzyme preparations in red winemaking. Int. J. Pure Appl. Sci. Technol. 2010, 1, 127–136. [Google Scholar]
- Mojsov, K.; Ziberoski, I.; Bozinovic, Z.; Petreska, M. Effects of pectolytic enzyme treatments on white grape mashs of Smedervka on grape juice yields and volume of lees. In Proceedings of the 46th Croatian and 6th International Symposium on Agriculture, Opatija, Croatia, 14–18 February 2011; pp. 968–971. [Google Scholar]
- Cosme, F.; Jordão, A.M. Grape phenolic composition and antioxidant capacity. In Wine—Phenolic Composition, Classification and Health Benefits; El Rayess, Y., Ed.; Nova Publishers: New York, NY, USA, 2014; pp. 1–40. [Google Scholar]
- Sommer, S.; Cohen, S.D. Comparison of different extraction methods to predict anthocyanin concentration and color characteristics of red wines. Fermentation 2018, 4, 39. [Google Scholar] [CrossRef]
- Reyes, N.; Rivas Ruiz, I.; Dominguez-Espinosa, R.; Solis, S. Influence of immobilization parameters on endopolygalacturonase productivity by hybrid Aspergillus sp. HL entrapped in calcium aliginate. Biochem. Eng. J. 2006, 32, 43–48. [Google Scholar] [CrossRef]
- Sario, K.; Demir, N.; Acar, J.; Mutlu, M. The use of commercial pectinase in the fruit industry, part 2: Determination of the kinetic behaviour of immobilized commercial pectinase. J. Food Eng. 2001, 47, 271–274. [Google Scholar]
- Romero, C.; Sanchez, S.; Manjon, S.; Iborra, J.L. Optimization of the pectinesterase/endo-d-polygalacturonase immobilization process. Enzym. Microb. Technol. 1989, 11, 837–843. [Google Scholar] [CrossRef]
- Lozano, P.; Manjon, A.; Iborra, J.L.; Canovas, M.; Romojaro, F. Kinetic and operational study of a cross-flow reactor with immobilized pectolytic enzymes. Enzym. Microb. Technol. 1990, 12, 499–505. [Google Scholar] [CrossRef]
- Ramirez, H.L.; Gómez Brizuela, L.; Úbeda Iranzo, J.; Areval-Villena, M.; Briones Pérez, A.I. Pectinase immobilization on a chitosan-coated chitin support. J. Food Proc. Eng. 2016, 39, 97–104. [Google Scholar] [CrossRef]
- Charoenchai, C.; Fleet, G.H.; Henschke, P.A.; Todd, B.E.N. Screening of non-Saccharomyces wine yeasts for the presence of extracellular hydrolytic enzymes. Aust. J. Grape Wine Res. 1997, 3, 2–8. [Google Scholar] [CrossRef]
- Fernández, M.; Úbeda, J.F.; Briones, A.I. Typing of non-Saccharomyces yeasts with enzymatic activities of interest in winemaking. Int. J. Food Microbiol. 2000, 59, 29–36. [Google Scholar] [CrossRef]
- Strauss, M.L.A.; Jolly, N.P.; Lambrechts, M.G.; van Rensburg, P. Screening for the production of extracellular hydrolytic enzymes by non-Saccharomyces wine yeasts. J. Appl. Microbiol. 2001, 91, 182–190. [Google Scholar] [CrossRef] [PubMed]
- Claus, H. Microbial Enzymes: Relevance for Winemaking. In Biology of Microorganisms on Grapes, in Must and in Wine, 2nd ed.; König, H., Unden, G., Fröhlich, J., Eds.; Springer International Publishing: Cham, Switzerland, 2017; pp. 315–338. [Google Scholar]
- Mateo, J.J.; Maicas, S. Application of Non-Saccharomyces yeasts to winemaking process. Fermentation 2016, 2, 14. [Google Scholar] [CrossRef]
- Merín, M.G.; Mendoza, L.M.; Farías, M.E.; de Ambrosini, V.I.M. Isolation and selection of yeast from wine grape ecosystem secreting cold-active pectinolytic activity. Int. J. Food Microbiol. 2011, 147, 144–148. [Google Scholar] [CrossRef] [PubMed]
- Sahay, S.; Hanid, B.; Singh, P.; Ranjan, K.; Chauhan, D.; Rana, R.S.; Chaurse, V.K. Evaluation of pectinolytic activities for oenological uses from psychrotrophic yeasts. Lett. Appl. Microbiol. 2013, 57, 115–121. [Google Scholar] [CrossRef] [PubMed]
- Merín, M.G.; de Ambrosini, V.I.M. Highly cold-active pectinases under wine-like conditions from non-Saccharomyces yeasts for enzymatic production during winemaking. Lett. Appl. Microbiol. 2015, 60, 467–474. [Google Scholar] [CrossRef] [PubMed]
- Gallander, J.F.; Peng, A.C. Lipid and fatty acid composition of different wine grapes. Am. J. Enol. Vitic. 1980, 31, 24–27. [Google Scholar]
- Pueyo, E.; Martinez-Rodriquez, A.; Polo, M.C.; Santa-Maria, G.; Bartomé, B. Release of lipids during yeast autolysis in model wine. J. Agric. Food Chem. 2000, 48, 116–122. [Google Scholar] [CrossRef] [PubMed]
- Fragopoulou, E.; Antonopoulou, S.; Demopoulos, C.A. Biologically active lipids with antiatherogenic properties from white wine and must. J. Agric. Food Chem. 2002, 50, 2684–2694. [Google Scholar] [CrossRef] [PubMed]
- Vakhlu, J.; Kour, A. Yeast lipases: Enzyme purification, biochemical properties and gene cloning. Electron. J. Biotechnol. 2006, 9. [Google Scholar] [CrossRef]
- Matthews, A.; Grbin, P.R.; Jiranek, V. A survey of lactic acid bacteria for enzymes of interest in oenology. Aust. J. Grape Wine Res. 20026, 12, 235–244. [Google Scholar] [CrossRef]
- Madrigal, T.; Maicas, S.; Tolosa, J.J.M. Glucose and ethanol tolerant enzymes produced by Pichia (Wickerhamomyces) isolates from enological ecosystems. Am. J. Enol. Vitic. 2013, 64, 126–133. [Google Scholar] [CrossRef]
- Molnárova, J.; Vadkertiová, R.; Stratilová, E. Extracellular enzymatic activities and physiological profiles of yeasts colonizing fruit trees. J. Basic Microbiol. 2014, 51, S74–S84. [Google Scholar] [CrossRef] [PubMed]
- Dimopoulou, M.; Lonvauf-Funel, A.; Dols-Lafargue, M. Polysaccharide production by grapes must and wine microorganisms. In Biology of Microorganisms on Grapes, in Must and in Wine, 2nd ed.; König, H., Unden, G., Fröhlich, J., Eds.; Springer International Publishing: Cham, Switzerland, 2017; pp. 241–258. [Google Scholar]
- Pozo-Bayón, M.A.; Monagas, M.; Bartolomé, B.; Moreno-Arribas, M.V. Wine features related to safety and consumer health: An integrated perspective. Crit. Rev. Food Sci. Nutr. 2012, 52, 31–54. [Google Scholar] [CrossRef] [PubMed]
- Campos, F.M.; Couto, J.A.; Hogg, T. Utilisation of natural and by-products to improve wine safety. In Wine Safety, Consumer Preference, and Human Health; Morena-Arribas, M.V., Bartolomé Sualdea, B., Eds.; Springer International Publishing: Cham, Switzerland, 2016; pp. 27–49. [Google Scholar]
- Marchal, R.; Jeandet, P. Use of enological additives for colloids and tartrate salt stabilization in white wines and for improvement of sparkling wine foaming properties. In Wine Chemistry and Biochemistry; Morena-Arribas, M.V., Polo, M.C., Eds.; Springer: New York, NY, USA, 2010; pp. 127–158. [Google Scholar]
- Venturi, F.; Andrich, G.; Quartacci, M.F.; Sanmartin, C.; Andrich, L.; Zinnai, A. A kinetic method to identify the optimum temperature for glucanase activity. S. Afr. J. Enol. Vitic. 2013, 34, 281–286. [Google Scholar] [CrossRef]
- Styger, G.; Prior, B.; Bauer, F.F. Wine flavor and aroma. J. Ind. Microbiol. 2011, 38, 1145–1159. [Google Scholar] [CrossRef] [PubMed]
- Ugliano, M.; Henschke, P.A. Yeasts and wine flavour. In Wine Chemistry and Biochemistry; Morena-Arribas, M.V., Polo, M.V., Eds.; Springer: New York, NY, USA, 2010; pp. 313–392. [Google Scholar]
- Hjelmeland, A.K.; Ebeler, S.E. Glycosidically bound volatile aroma compounds in grapes and wine: A review. Am. J. Enol. Vitic. 2015, 66, 1–10. [Google Scholar] [CrossRef]
- Mateo, J.J.; DiStefano, R. Description of the beta-glucosidase activity of wine yeasts. Food Microbiol. 1997, 14, 583–591. [Google Scholar] [CrossRef]
- Maicas, S.; Mateo, J.J. Microbial glycosidases for wine production. Beverages 2016, 2, 20. [Google Scholar] [CrossRef]
- Perez-Martin, F.; Sesena, S.; Miguel Izquierdo, P.; Martin, R.; Llanos Palop, M. Screening for glycosidase activities of lactic acid bacteria as a biotechnological tool in oenology. World J. Microbiol. Biotechnol. 2012, 28, 1423–1432. [Google Scholar] [CrossRef] [PubMed]
- Michlmayer, H.; Nauer, S.; Brandes, W.; Schumann, C.; Kulbe, K.D.; del Hierro, A.M.; Eder, R. Release of wine monoterpenes from natural precursors by glycosidases from Oenococcus oeni. Food Chem. 2012, 135, 80–87. [Google Scholar] [CrossRef]
- Iranzo, J.F.U.; Pérez, A.I.B.; Cañas, P.M.I. Study of oenological characteristics and enzymatic activities of wine yeasts. Food Microbiol. 1998, 15, 399–406. [Google Scholar] [CrossRef]
- Zoecklein, B.; Marcy, J.; Williams, S.; Jasinski, Y. Effect of native yeasts and selected strains of Saccharomyces cerevisiae on glycosyl glucose, potential volatile terpenes, and selected aglycons of white Riesling (Vitis vinfera L.) wines. J. Food Comp. Anal. 1997, 10, 55–65. [Google Scholar] [CrossRef]
- Wang, Y.; Zhang, C.; Xu, Y.; Li, J. Evaluating potential applications of indigenous yeasts and their β-glucosidases. J. Inst. Brew. 2015, 121, 642–648. [Google Scholar] [CrossRef]
- Delcroix, A.; Gunata, Z.; Sapis, L.C.; Salmon, J.M.; Baynone, C. Glycosidase activities of three enological yeast strains during winemaking: Effect on the terpenol content of Muscat wine. Am. J. Enol. Vitic. 1994, 45, 291–296. [Google Scholar]
- Sabel, A.; Martens, S.; Petri, A.; König, H.; Claus, H. Wickerhamomyces anomalus AS1: A new strain with potential to improve wine aroma. Anal. Microbiol. 2014, 64, 483–491. [Google Scholar] [CrossRef]
- Rodríguez, M.E.; Lopes, C.A.; van Broock, M.; Valles, S.; Ramón, D.; Caballero, A.C. Screening and typing of Patagonian wine yeasts for glycosidase activities. J. Appl. Microbiol. 2004, 96, 84–95. [Google Scholar] [CrossRef] [PubMed]
- Gonzales-Pombo, O.; Farina, L.; Carreau, F.; Batista-Viera, F.; Brena, B.M. A novel extracellular beta-glucosidase from Issatschenkia terricola: Immobilization and application for aroma enhancement of white Muscat wine. Process Biochem. 2011, 46, 385–389. [Google Scholar] [CrossRef]
- Hu, K.; Zhu, X.L.; Mu, H.; Ma, Y.; Ullah, N.; Tao, Y.S. A novel extracellular glycosidase activity from Rhodotorula mucilaginosa: Its application potential in wine aroma enhancement. Lett. Appl. Microbiol. 2016, 62, 169–176. [Google Scholar] [CrossRef] [PubMed]
- López, M.C.; Mateo, J.J.; Maicas, S. Screening of β-glucosidase and β-xylosidase activities in four non-Saccharomyces yeast isolates. J. Food Sci. 2015, 80, C1696–C1704. [Google Scholar] [CrossRef] [PubMed]
- Schwentke, J.; Sabel, A.; Petri, A.; König, H.; Claus, H. The wine yeast Wickerhamomyces anomalus AS1 secretes a multifunctional exo-β-1,3 glucanase with implications for winemaking. Yeast 2014, 31, 349–359. [Google Scholar] [CrossRef] [PubMed]
- El Rayess, Y. Wine: Phenolic Composition, Classification and Health Benefits; Nova Publishers: New York, NY, USA, 2014; ISBN 978-1-63321-048-6. [Google Scholar]
- Padilla, B.; Gil, J.V.; Manzanares, P. Past and future of Non-Saccharomyces yeasts: From spoilage microorganisms to biotechnological tools for improving wine aroma complexity. Front. Microbiol. 2016, 7, 111. [Google Scholar] [CrossRef] [PubMed]
- Saerens, S.M.G.; Delvaux, F.; Verstrepen, K.J.; van Dijck, P.; Thevelein, J.M.; Delvaux, F.R. Parameters affecting ethyl ester production by Saccharomyces cerevisiae during fermentation. Appl. Environ. Microbiol. 2008, 74, 454–461. [Google Scholar] [CrossRef] [PubMed]
- Maicas, S.; Gil, J.V.; Pardo, I.; Ferrer, S. Improvement of volatile composition of wines by controlled addition of malolactic bacteria. Food Res. Int. 1999, 32, 491–496. [Google Scholar] [CrossRef]
- Matthews, A.; Grbin, P.R.; Jiranek, V. Biochemical characterization of the esterase activities of wine lacti acid bacteria. Appl. Microbiol. Biotechnol. 2007, 77, 329–337. [Google Scholar] [CrossRef] [PubMed]
- Fia, G.; Oliver, V.; Cavaglioni, A.; Canuti, V.; Zanoni, B. Side activities of commercial enzyme preparations and their influence on hydroxycinnamic acids, volatile compounds and nitrogenous components of white wine. Aust. J. Grape Wine Res. 2016, 22, 366–375. [Google Scholar] [CrossRef]
- Van Sluyter, S.C.; McRae, J.M.; Falconer, R.J.; Smith, P.A.; Bacic, A.; Waters, E.J.; Marangon, M. Wine protein haze: Mechanisms of formation and advances in prevention. J. Agric. Food Chem. 2015, 63, 4020–4030. [Google Scholar] [CrossRef] [PubMed]
- Weber, P.; Kratzin, H.; Brockow, K.; Ring, J.; Steinhart, H.; Paschke, A. Lysozyme in wine: A risk evaluation for consumers allergic to hen’s egg. Mol. Nutr. Food Res. 2009, 53, 1469–1477. [Google Scholar] [CrossRef] [PubMed]
- Peñas, E.; di Lorenzo, C.; Uberti, F. Allergenic proteins in enology: A review on technological applications and safety aspects. Molecules 2015, 20, 13144–13174. [Google Scholar] [CrossRef] [PubMed]
- Rizzi, C.; Mainente, F.; Pasini, G.; Simonato, B. Hidden exogenous proteins in wine: Problems, methods of detection and related legislation—A review. Czech J. Food Sci. 2016, 34, 93–104. [Google Scholar] [CrossRef]
- Selitrennikoff, C.P. Antifungal proteins. Appl. Environ. Microbiol. 2001, 67, 2883–2894. [Google Scholar] [CrossRef] [PubMed]
- Jaeckels, N.; Tenzer, S.; Rosch, A.; Scholten, G.; Decker, H.; Fronk, P. β-Glucosidase removal due to bentonite fining during wine making. Eur. Food Res. Technol. 2015, 241, 253–262. [Google Scholar] [CrossRef]
- Esti, M.; Benucci, I.; Lombardelli, C.; Liburdi, K.; Garzillo, A.M.V. Papain from papaya (Carica papaya L.) fruit and latex: Preliminary characterization in alcoholic-acidic buffer for wine application. Food Bioprod. Process. 2013, 91, 595–598. [Google Scholar] [CrossRef]
- Benucci, I.; Esti, M.; Liburdi, K. Effect of free and immobilised stem bromelain on protein haze in white wine. Aust. J. Grape Wine Res. 2014, 20, 347–352. [Google Scholar] [CrossRef]
- Manrangon, M.; van Sluyter, S.C.; Robinson, E.M.C.; Muhlack, R.A.; Holt, H.E.; Haynes, P.A.; Godden, P.W.; Smith, P.A.; Waters, E.J. Degradation of white wine haze proteins by Aspergillopepsin I and II during flash pasteurization. Food Chem. 2012, 135, 1157–1165. [Google Scholar] [CrossRef] [PubMed]
- Van Sluyter, S.C.; Warnock, N.I.; Schmidt, S.; Anderson, P.; van Kan, J.A.L.; Bacic, A.; Waters, E.J. Aspartic acid protease from Botrytis cinerea removes haze-forming proteins during white winemaking. J. Agric. Food Chem. 2013, 61, 9705–9711. [Google Scholar] [CrossRef] [PubMed]
- Dizy, M.; Bisson, L.F. Proteolytic activity of yeast strains during grape juice fermentation. Am. J. Enol. Vitic. 2000, 51, 155–167. [Google Scholar]
- Younes, B.; Cilindre, C.; Villaume, S.; Parmentier, M.; Jeandet, P.; Vasserot, Y. Evidence for an extracellular and proteolytic activity secreted by living cells of Saccharomyces cerevisiae PIR1: Impact on grape proteins. J. Agric. Food Chem. 2011, 59, 6239–6246. [Google Scholar] [CrossRef] [PubMed]
- Younes, B.; Cilindre, C.; Jeandet, P.; Vasserot, Y. Enzymatic hydrolysis of thermos-sensitive grape proteins by a yeast protease as revealed by a proteomic approach. Food Res. Int. 2013, 54, 1298–1301. [Google Scholar] [CrossRef]
- Song, L.; Chen, Y.; Du, Y.; Wang, X.; Guo, X.; Dong, J.; Xiao, D. Saccharomyces cerevisiae proteinase A excretion and wine making. World J. Microbiol. Biotechnol. 2017, 33, 210. [Google Scholar] [CrossRef] [PubMed]
- Kang, H.A.; Choi, E.S.; Hong, W.K.; Kim, J.Y.; Ko, S.M.; Sohn, J.H.; Rhee, S.K. Proteolytic stability of recombinant human serum albumin secreted in the yeast Saccharomyces cerevisiae. Appl. Microbiol. Biotechnol. 2000, 53, 575–582. [Google Scholar] [CrossRef] [PubMed]
- Schlander, M.; Distler, U.; Tenzer, S.; Thines, E.; Claus, H. Purification and properties of yeast proteases secreted by Wickerhamomyces anomalus 227 and Metschnikowia pulcherrima 446 during growth in a white grape juice. Fermentation 2017, 3, 2. [Google Scholar] [CrossRef]
- Theron, L.W.; Bely, M.; Divol, B. Characterisation of the enzymatic properties of MpAPr1, an aspartic protease secreted by the wine yeast Metschikowia pulcherrima. J. Sci. Food Agric. 2017, 97, 3584–3593. [Google Scholar] [CrossRef] [PubMed]
- Theron, L.W.; Bely, M.; Divol, B. Monitoring the impact of an aspartic protease (MpApr1) on grape proteins and wine properties. Appl. Microbiol. Biotechnol. 2018, 102, 5173–5183. [Google Scholar] [CrossRef] [PubMed]
- Folio, P.; Ritt, J.F.; Alexandre, H.; Remize, F. Characterization of EprA, a major extracellular protein of Oenococcus oeni with protease activity. Int. J. Food Microbiol. 2008, 127, 26–31. [Google Scholar] [CrossRef] [PubMed]
- Reid, V.J.; Theron, L.W.; du Toit, M.; Divol, B. Identification and partial characterization of extracellular aspartic protease genes from Metschnikowia pulcherrima IWBT Y1123 and Candida apicola IWBT Y1384. Appl. Environ. Microbiol. 2012, 78, 6838–6849. [Google Scholar] [CrossRef] [PubMed]
- Mateo, J.J.; Maicas, S.; Thießen, C. Biotechnological characterisation of extracellular proteases produced by enological Hanseniaspora isolates. Int. J. Food Sci. Technol. 2015, 50, 218–225. [Google Scholar] [CrossRef]
- Lagace, L.S.; Bisson, L.F. Survey of yeast acid proteases for effectiveness of wine haze reduction. Am. J. Enol. Vitic. 1990, 41, 147–155. [Google Scholar]
- Chasseriaud, L.; Miot-Sertier, C.; Coulon, J.; Iturmendi, N.; Moine, V.; Albertin, W.; Bely, M. A new method for monitoring the extracellular proteolytic activity of wine yeasts during alcoholic fermentation of grape must. J. Microbiol. Methods 2015, 119, 176–179. [Google Scholar] [CrossRef] [PubMed]
- Claus, H.; Sabel, A.; König, H. Wine phenols and laccase: An ambivalent relationship. In Wine, Phenolic Composition, Classification and Health Benefits; Rayess, Y.E., Ed.; Nova Publishers: New York, NY, USA, 2014; pp. 155–185. [Google Scholar]
- Claus, H.; Decker, H. Bacterial tyrosinases. Syst. Appl. Microbiol. 2006, 29, 3–14. [Google Scholar] [CrossRef] [PubMed]
- Fronk, P.; Hartmann, H.; Bauer, M.; Solem, E.; Jaenicke, E.; Tenzer, S.; Decker, H. Polyphenoloxidase from Riesling and Dornfelder wine grapes (Vitis vinfera) is a tyrosinase. Food Chem. 2015, 183, 49–57. [Google Scholar] [CrossRef] [PubMed]
- Riebel, M.; Sabel, A.; Claus, H.; Fronk, P.; Xia, N.; Li, H.; König, H.; Decker, H. Influence of laccase and tyrosinase on the antioxidant capacity of selected phenolic compounds on human cell lines. Molecules 2015, 20, 17194–17207. [Google Scholar] [CrossRef] [PubMed]
- Riebel, M.; Sabel, A.; Claus, H.; Xia, N.; Li, H.; König, H.; Decker, H.; Fronk, P. Antioxidant capacity of phenolic compounds on human cell lines as affected by grape-tyrosinase and Botrytis-laccase oxidation. Food Chem. 2017, 229, 779–789. [Google Scholar] [CrossRef] [PubMed]
- Sabel, A.; Bredefeld, S.; Schlander, M.; Claus, H. Wine phenolic compounds: Antimicrobial properties against yeasts, lactic acid and acetic acid bacteria. Beverages 2017, 3, 29. [Google Scholar] [CrossRef]
- Zinnai, A.; Venturi, F.; Sanmartin, C.; Quartacci, M.F.; Andrich, G. Chemical and laccase catalysed oxidation of gallic acid: Determination of kinetic parameters. Res. J. Biotechnol. 2013, 6, 62–65. [Google Scholar]
- Servili, M.; de Stefano, G.; Piacquadio, P.; Sciancalepore, V. A novel method for removing phenols from grape must. Am. J. Enol. Vitic. 2000, 51, 357–361. [Google Scholar]
- Minussi, R.C.; Rossi, M.; Bolgna, L.; Rotilio, D.; Pastore, G.M.; Durán, N. Phenols removal in musts; strategy for wine stabilization by laccase. J. Mol. Catal. B Enzym. 2007, 45, 102–107. [Google Scholar] [CrossRef]
- Maier, G.; Dietrich, H.; Wucherpfennig, K. Winemaking without SO2-with the aid of enzymes? Weinwirtschaft-Technik 1990, 126, 18–22. [Google Scholar]
- Brenna, O.; Bianchi, E. Immobilized laccase for phenolic removal in must and wine. Biotechnol. Lett. 1994, 16, 35–40. [Google Scholar] [CrossRef]
- Lettera, V.; Pezzella, C.; Cicatiello, P.; Piscitelli, A.; Giacobelli, V.G.; Galano, E.; Amoresano, A.; Sannia, G. Efficient immobilization of a fungal laccase and its exploitation in fruit juice clarification. Food Chem. 2016, 196, 1272–1278. [Google Scholar] [CrossRef] [PubMed]
- Lustrato, G.; De Leonardis, A.; Macciola, V.; Ranalli, G. Preliminary lab scale of advanced techniques as new tools to reduce ethylphenols content in synthetic wine. Agro Food Ind. Hi-Tech 2015, 26, 51–54. [Google Scholar]
- Smit, A.A.; du Toit, W.J.; du Toit, M. Biogenic amines in wine: Understanding the headache. S. Afr. J. Enol. Vitic. 2008, 29, 109–127. [Google Scholar] [CrossRef]
- Guo, Y.Y.; Yang, Y.P.; Peng, Q.; Han, Y. Biogenic amines in wine: A review. Int. J. Food Sci. Technol. 2015, 50, 1523–1532. [Google Scholar] [CrossRef]
- Preti, R.; Vieri, S.; Vinci, G. Biogenic amine profiles and antioxidant properties of Italian red wines from different price categories. J. Food Comp. Anal. 2016, 46, 7–14. [Google Scholar] [CrossRef]
- Sebastian, P.; Herr, P.; Fischer, U.; König, H. Molecular identification of lactic acid bacteria occurring in must and wine. S. Afr. J. Enol. Vitic. 2011, 32, 300–309. [Google Scholar] [CrossRef]
- Christ, E.; König, H.; Pfeiffer, P. Bacterial formation of biogenic amines in grape juice: Influence of culture conditions. Deutsche Lebensmittel-Rundschau 2012, 108, 73–78. [Google Scholar]
- Henríquez-Aedo, K.; Durán, D.; Garcia, A.; Hengst, M.B.; Aranda, M. Identification of biogenic amines-producing lactic acid bacteria isolated from spontaneous malolactic fermentation of Chilean red wines. LWT Food Sci. Technol. 2016, 68, 183–189. [Google Scholar] [CrossRef]
- Moreno-Arribas, M.V.; Polo, M.C. (Eds.) Amino acids and biogenic amines. In Wine Chemistry and Biochemistry; Springer: New York, NY, USA, 2010; pp. 163–189. [Google Scholar]
- Kushnereva, E.V. Formation of biogenic amines in wine production. Appl. Biochem. Microbiol. 2015, 51, 108–112. [Google Scholar] [CrossRef]
- Yagodina, O.V.; Nikol’skaya, E.B.; Khovanskikh, A.E.; Kormilitsyn, B.N. Amine oxidases of microorganisms. J. Evol. Biochem. Physiol. 2002, 38, 251–258. [Google Scholar] [CrossRef]
- Klinman, J.P. The multi-functional topa-quinone copper amine oxidases. Biochim. Biophys. Acta 2003, 1647, 131–137. [Google Scholar] [CrossRef]
- Corpillo, D.; Valetti, F.; Giuffrida, M.G.; Conti, A.; Rossi, A.; Finazzi-Agrò, A.; Giunta, C. Induction and characterization of a novel amine oxidase from the yeast Kluyveromyces marxianus. Yeast 2003, 20, 369–379. [Google Scholar] [CrossRef] [PubMed]
- Bäumlisberger, M.; Moellecken, U.; König, H.; Claus, H. The potential of the yeast Debaryomyces hansenii H525 to degrade biogenic amines in food. Microorganisms 2015, 3, 839–850. [Google Scholar] [CrossRef] [PubMed]
- Callejón, S.; Sendra, R.; Ferrer, S.; Pardo, I. Identification of a novel enzymatic activity from lactic acid bacteria able to degrade biogenic amines in wine. Appl. Microbiol. Biotechnol. 2014, 98, 185–198. [Google Scholar] [CrossRef] [PubMed]
- Callejón, S.; Sendra, R.; Ferrer, S.; Pardo, I. Cloning and characterization of a new laccase from Lactobacillus plantarum J16 CECT 8944 catalyzing biogenic amine degradation. Appl. Microbiol. Biotechnol. 2016, 100, 3113–3124. [Google Scholar] [CrossRef] [PubMed]
- Lonvaud-Funel, A. Undesirable compounds and spoilage microorganisms in wine. In Wine Safety, Consumer Preference, and Human Health; Morena-Arribas, M.V., Bartolomé Sualdea, B., Eds.; Springer International Publishing: Cham, Switzerland, 2016; pp. 3–26. [Google Scholar]
- König, H.; Fröhlich, J. Lactic acid bacteria. In Biology of Microorganisms on Grapes, in Must and in Wine, 2nd ed.; Springer International Publishing: Cham, Switzerland, 2017. [Google Scholar]
- Liburdi, K.; Benucci, I.; Esti, M. Lysozyme in wine: An overview of current and future applications. Compr. Rev. Food Sci. Food Saf. 2014, 13, 1062–1073. [Google Scholar] [CrossRef]
- Mojsov, K.; Petreska, M.; Ziberoski, J. Risks of microbial spoilage in wine. In Proceedings of the EHEDG World Congress on Hygienic Engineering & Design, Ohrid, Macedonia, 22–24 September 2011. [Google Scholar]
- Blättel, V.; Wirth, K.; Claus, H.; Schlott, P.; Pfeiffer, P.; König, H. A lytic enzyme cocktail from Streptomyces sp. B578 for the control of lactic and acid bacteria in wine. Appl. Microbiol. Biotechnol. 2009, 83, 839–848. [Google Scholar] [CrossRef] [PubMed]
- Sommer, S.; Wegmann-Herr, P.; Wacker, M.; Fischer, U. Influence of lysozyme addition on hydroxycinnamic acids and volatile phenols during wine fermentation. Fermentation 2018, 4, 5. [Google Scholar] [CrossRef]
- Gonzales, R.; Tronchoni, J.; Quirós, M.; Morales, P. Genetic improvement and genetically modified microorganisms. In Wine Safety, Consumer Preference, and Human Heath; Morena-Arribas, M.V., Bartolomé Sualdea, B., Eds.; Springer International Publishing: Cham, Switzerland, 2016; pp. 71–96. [Google Scholar]
- Pretorius, I.S. Tailoring wine yeast for the new millenium: Novel approaches to the ancient art of winemaking. Yeast 2000, 16, 675–729. [Google Scholar] [CrossRef]
- Pretorius, I.S. Conducting wine symphonics with the aid of yeast genomics. Beverages 2016, 2, 36. [Google Scholar] [CrossRef]
Figure 1. Color extraction from red grapes after a model fermentation without and in presence of a yeast lipase (Claus, unpublished data).
Figure 2. Wine browning by Botrytis-laccase (right).
Table 1. Enzymes used for winemaking and their function.
|Enhancement of filtration/clarification of must||Pectinolytic enzymes||Degradation of viscosity (pectin)|
|Mash fermentation/heating (red wine)||Pectinase with side activities (cellulases, hemicellulases)||Hydrolysis of plant cell wall polysaccharides. Improvement of skin maceration and color extraction of grapes, quality, stability, filtration of wines|
|Late phase of fermentation (white wine)||Glycosidases||Improvement of aroma by splitting sugar residues from odorless precursors|
|Young wine||Glucanases||Lysis of yeast cell walls, release of mannoproteins|
|Contaminated juice||Glucanases||Lysis of microbial exopolysacharides to improve clarification|
|Wine||Urease||Hydrolysis of yeast derived urea, preventing formation of ethyl carbamate|
|Must, wine||Lysozyme from hen egg||Control of bacterial growth|
|Must, wine||Proteases||Wine stabilization by prevention of protein haze; Reduction of bentonite demand|
Table 2. Microbial enzymes with relevance for winemaking.
|Fungi (Botrytis cinerea)|
|Glycosidases||Influence aromatic potential of infected grapes by release of volatile aroma compounds|
|Laccases||Broad specificity to phenolic compounds, cause oxidation and browning|
|Pectinases||Depolymerizing enzymes, cause degradation of plant cell walls and grape rotting|
|Cellulases||Multi-component complexes: endo-, exoglucanases and cellobiases; synergistic working, degrade plant cell walls|
|Lipases||Degrade lipids (e.g., in cell membranes)|
|Esterases||Involved in ester formation and degradation|
|Proteases||Aspartic proteases occur early in fungal infection, determine rate and extent of rotting caused by pectinases|
|Glucosidases||Some yeasts produce β-glucosidases which are not repressed by glucose and are resistant to ethanol and low pH; positive influence on wine flavor|
|Glucanases||Occur extracellular, cell wall associated and intracellular, accelerate autolysis process and release of mannoproteins|
|Proteases||Acidic endoproteases accelerate autolysis process and degradation of grape proteins|
|Pectinases||Degrade pectin in grape cell walls|
|Lactic acid bacteria|
|Malolactic enzymes||Convert malic acid to lactic acid|
|Esterases||Involved in ester formation and degradation|
|Glycosidases||Deliberate flavor compounds|
|Lichenases, Glucanases, Cellulases, Xylanases||Degradation of polysaccharides|
|Proteases||Hydrolysis of proteins|
|Tannases||Hydrolysis of tannins (polymeric phenolic compounds)|
|Laccases||Oxidation of phenolic compounds|
|Supplier||Enzyme Preparation||Purpose of Application|
|AEB, South Africa||Pectocel L||Improvement of clarification, filtration and product yield|
|Endozym Pectoflot||Improvement of clarification, filtration and product yield|
|Endozym Contact Pelliculaire||Enhancement of extraction and color stabilization|
|Endozym Rouge||Enhancement of extraction and color stabilization|
|Endozyme Active||Improvement of clarification, filtration and product yield|
|Begerow, Germany||Siha Panzym Extract G||Enhanced extraction and release of color and aroma|
|Siha Panzym Clair Rapide G||Improvement of clarification, filtration and product yield|
|Siha Panzym Fino G (β-Glucanase)||Improvement of clarification, filtration and sensory|
|Siha Panzym Arome G (β-Glucosidase)||Enhanced aroma development|
|Darleon, South Africa||Influence||Improvement of clarification, filtration and product yield|
|Enzym’ Color Plus||Enhancement of extraction and color stabilization|
|DSM, Switzerland||Rapidase Filtration||Improvement of clarification, filtration and product yield|
|Rapidase Vino Super||Improvement of clarification, filtration and product yield|
|Enartis, Italy||Uvazym 1000S||Clarification of white juices—facilitation of fining and filtration|
|Progress Quick||Must flotation|
|Uvazym couleur||Enhanced extraction during short macerations|
|Erbslöh, Germany||Trenolin bukett DF (β-Glycosidase)||Enhanced aroma development—Improvement of clarification|
|Trenolin Super DF||Improvement of clarification, filtration and product yield|
|Trenolin Flot DF||Must flotation|
|Trenolin 4000 DF||Enhancement of sugar yield|
|Trenolin Filtro DF (β-Glucanase)||Improvement of clarification and filtration; Hydrolysis of Botrytis cinerea exopolysaccharide slime|
|Trenolin Bukett DF||Enhance of color and aroma release from red grapes|
|Laffort, France||Lafazym press||Enhanced color and tannin extraction—Facilitation of fining and filtration|
|Lafazym CL||Improvement of clarification, filtration and product yield|
|Lafase 60||Improvement of clarification, filtration and product yield|
|Lafase HE||Enhancement of extraction and color stabilization|
|Lallemand, France||Lallemand EX||Enhancement of extraction and color stabilization|
|Lallemand OE||Enhancement of extraction and color stabilization|
|Novo Nordisk, Denmark||Novoclair FCE||Improvement of clarification, filtration and product yield|
|Vinozym EC||Enhancement of extraction and color stabilization|
|Glucanex (β-Glucanase)||Improvement of clarification and filtration; Hydrolysis of Botrytis cinerea exopolysaccharide slime|
|Ultrazym||Improvement of clarification and filtration|
|Pectinex Superpress||Improvement of clarification and filtration|
|Valley Research, USA||Crystalzyme||Rapid clarification–Color improvement–Increased complexity–Process efficiency|
|Candida albicans||Endo-β-1,3-||L, OL, P||49|
|Candida pulcherrima||nd||G, Li||nd|
|Candida stellata||nd||G, Li||nd|
|Candida utilis||Endo-β-1-3-||L, PNPG||20|
|Exo-β-1,3-1,6-||L, P, PNPG||20|
|Kloeckera apiculata||nd||G, Li||nd|
|Kluyveromyces phaseolosporus||Endo-β-1,3-(I)||L, OL||180|
|Exo-β-1,3-1,6-(IV)||L, Ol, P||8.7|
|Pichia polymorpha||Endo-β-1,3-(I)||L, OL||47|
|Exo-β-1,3-1,6-(II)||L, OL, P, PNPG||40|
|Schizosaccharomyces pombe||Endo-β-1,3-(I)||L, OL||160|
|Schizosaccharomyces versatilis||Endo-β-1,3-||L, OL||97|
|Exo-β-1,3-1,6-||L, P, PNPG||43|
|Wickerhamomyces anomalus AS1||Exo-β-1,3-||L, PNPG||47.5|
L: laminarin, OL: oxidized laminarin, P: pustulan, G: β-glucan (Barley), Li: lichenan, PNPG: p-nitro-phenyl-β-d-glucoside; nd: not determined.
Table 5. Aroma enhancing enzymes of non-Saccharomyces yeasts with possible use for wine fermentation modified from .
* Activity detected (+).
Table 6. Extracellular proteases of non-Saccharomyces yeasts with possible use for wine fermentation.
|Species||Mode of Identification||Characterization||Reference|
|Candida apicola||Skim milk agar (pH 3.5), Gene Sequencing||Aspartic protease CaPR1 (39.2 kDa)|||
|Candida stellata||Casein agar||nd|||
|Hanseniaspora guelliermondii Hansenispora valbyenis Hanseniapora occidentalis||Casein agar and broth (pH 6.0)||nd|||
|Hanseniaspora uvarum||Skim milk agar (pH 3.5)||nd|||
|Kloeckera apiculata||Enzymatic; Inhibitor studies||Acid endopeptidase|||
|Metschnikowia pulcherrima||Skim milk agar (pH 3.5)||nd|||
|Azocasein hydrolysis during fermentation of grape must||nd|||
|Skim milk agar (pH 3.5), Sequencing of protease gene, Purification||Aspartic protease pAPR1 (40.8 kDa)||[75,78]|
|Skim milk agar (pH 4.5), Enzymatic; Inhibitor studies, LC-MS/MS||Aspartic protease|||
|Wickerhamomyces anomalus||Skim milk agar (pH 3.5)||nd|||
|Skim milk agar (pH 4.5), Enzymatic; Inhibitor studies, LC-MS/MS||Aspartic protease WaAPR1 (47 kDa)|||
nd: not determined.
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