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Fermentation, Volume 4, Issue 4 (December 2018)

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Open AccessArticle Bioconversion of Kaempferol and Quercetin Glucosides from Plant Sources Using Rhizopus spp.
Fermentation 2018, 4(4), 102; https://doi.org/10.3390/fermentation4040102 (registering DOI)
Received: 30 October 2018 / Revised: 29 November 2018 / Accepted: 3 December 2018 / Published: 7 December 2018
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Abstract
Fermentation with filamentous fungi is known for the ability to convert bioactive compounds. The aim of this research was to investigate the metabolism of glycosidic derivatives of kaempferol and quercetin during fungal fermentation of extracts from cauliflower outer leaves and onion by Rhizopus
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Fermentation with filamentous fungi is known for the ability to convert bioactive compounds. The aim of this research was to investigate the metabolism of glycosidic derivatives of kaempferol and quercetin during fungal fermentation of extracts from cauliflower outer leaves and onion by Rhizopus oryzae and R. azygosporus. The highest release of kaempferol and quercetin was observed after 2 days and 1 day of fermentation with R. oryzae, respectively. It was proposed that glycosidic compounds were initially deglycosylated to form kaempferol-3-glucoside and quercetin-3-glucoside and then further metabolized into their aglycones. Clear differences in conversion efficiency towards the aglycones were observed between the two Rhizopus strains. Although both flavonoids only differ in one hydroxyl group, the metabolism of the glycosides towards their respective aglycones, kaempferol or quercetin, was different. It is concluded that the fermentation with R. oryzae and R. azygosporus could be considered as a way to produce kaempferol and quercetin aglycone from their glycosidic derivatives. Full article
(This article belongs to the Special Issue Fermentation and Bioactive Metabolites)
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Open AccessCommunication Biotransformation of Ganoderic Acid A to 3-O-Acetyl Ganoderic Acid A by Soil-isolated Streptomyces sp.
Fermentation 2018, 4(4), 101; https://doi.org/10.3390/fermentation4040101
Received: 22 October 2018 / Revised: 13 November 2018 / Accepted: 28 November 2018 / Published: 1 December 2018
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Abstract
The medicinal fungus Ganoderma lucidum contains many bioactive triterpenoids, ganoderic acid A (GAA) being one of the major ones. The present study explored the microbial biotransformation of GAA, isolating 283 strains of soil actinomycetes and determining their abilities to biotransform GAA with ultra-performance
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The medicinal fungus Ganoderma lucidum contains many bioactive triterpenoids, ganoderic acid A (GAA) being one of the major ones. The present study explored the microbial biotransformation of GAA, isolating 283 strains of soil actinomycetes and determining their abilities to biotransform GAA with ultra-performance liquid chromatography analysis. One positive strain, AI 045, was selected to validate the biotransformation activity. The strain was identified as Streptomyces sp. based on the sequenced 16S rRNA gene. The produced compound obtained from the biotransformation of GAA was purified with the preparative high-performance liquid chromatography method and identified as 3-O-acetyl GAA based on mass and nuclear magnetic resonance spectral data. The present study is the first report that bacteria have the novel ability to biotransform the triterpenoids of fungus G. lucidum. Moreover, the identified 3-O-acetyl GAA is a new triterpenoid product discovered in microbes. Full article
(This article belongs to the Special Issue Fermentation and Bioactive Metabolites)
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Open AccessReview Seaweed Bioethanol Production: A Process Selection Review on Hydrolysis and Fermentation
Fermentation 2018, 4(4), 99; https://doi.org/10.3390/fermentation4040099
Received: 31 October 2018 / Revised: 20 November 2018 / Accepted: 27 November 2018 / Published: 29 November 2018
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Abstract
The rapid depletion and environmental concerns associated with the use of fossil fuels has led to extensive development of biofuels such as bioethanol from seaweeds. The long-term prospect of seaweed bioethanol production however, depends on the selection of processes in the hydrolysis and
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The rapid depletion and environmental concerns associated with the use of fossil fuels has led to extensive development of biofuels such as bioethanol from seaweeds. The long-term prospect of seaweed bioethanol production however, depends on the selection of processes in the hydrolysis and fermentation stages due to their limiting effect on ethanol yield. This review explored the factors influencing the hydrolysis and fermentation stages of seaweed bioethanol production with emphasis on process efficiency and sustainable application. Seaweed carbohydrate contents which are most critical for ethanol production substrate selection were 52 ± 6%, 55 ± 12% and 57 ± 13% for green, brown and red seaweeds, respectively. Inhibitor formation and polysaccharide selectivity were found to be the major bottlenecks influencing the efficiency of dilute acid and enzymatic hydrolysis, respectively. Current enzyme preparations used, were developed for starch-based and lignocellulosic biomass but not seaweeds, which differs in polysaccharide composition and structure. Also, the identification of fermenting organisms capable of converting the heterogeneous monomeric sugars in seaweeds is the major factor limiting ethanol yield during the fermentation stage and not the SHF or SSF pathway selection. This has resulted in variations in bioethanol yields, ranging from 0.04 g/g DM to 0.43 g/g DM. Full article
(This article belongs to the Special Issue Ethanol and Value-Added Co-Products)
Open AccessReview A Review of Seaweed Pre-Treatment Methods for Enhanced Biofuel Production by Anaerobic Digestion or Fermentation
Fermentation 2018, 4(4), 100; https://doi.org/10.3390/fermentation4040100
Received: 2 November 2018 / Revised: 23 November 2018 / Accepted: 27 November 2018 / Published: 29 November 2018
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Abstract
Macroalgae represent a potential biomass source for the production of bioethanol or biogas. Their use, however, is limited by several factors including, but not restricted to, their continuous supply for processing, and low biofuel yields. This review examines recent pre-treatment processes that have
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Macroalgae represent a potential biomass source for the production of bioethanol or biogas. Their use, however, is limited by several factors including, but not restricted to, their continuous supply for processing, and low biofuel yields. This review examines recent pre-treatment processes that have been used to improve the yields of either biogas or bioethanol from macroalgae. Factors that can influence hydrolysis efficiency and, consequently, biofuel yields, are highly affected by macroalgal composition, including content of salts, heavy metals, and polyphenols, structural make-up, as well as polysaccharide composition and relative content of carbohydrates. Other factors that can influence biofuel yield include the method of storage and preservation. Full article
(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)
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Open AccessEditorial Yeast Biotechnology 2.0
Fermentation 2018, 4(4), 98; https://doi.org/10.3390/fermentation4040098
Received: 31 October 2018 / Revised: 20 November 2018 / Accepted: 22 November 2018 / Published: 23 November 2018
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Abstract
Yeast biotechnology. [...] Full article
(This article belongs to the Special Issue Yeast Biotechnology 2.0)
Open AccessArticle Two-Stage Aeration Fermentation Strategy to Improve Bioethanol Production by Scheffersomyces stipitis
Fermentation 2018, 4(4), 97; https://doi.org/10.3390/fermentation4040097
Received: 28 October 2018 / Revised: 15 November 2018 / Accepted: 16 November 2018 / Published: 20 November 2018
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Abstract
Hardwood spent sulfite liquor (HSSL) is a by-product from pulp industry with a high concentration of pentose sugars, besides some hexoses suitable for bioethanol production by Scheffersomyces stipitis. The establishment of optimal aeration process conditions that results in specific microaerophilic conditions required by
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Hardwood spent sulfite liquor (HSSL) is a by-product from pulp industry with a high concentration of pentose sugars, besides some hexoses suitable for bioethanol production by Scheffersomyces stipitis. The establishment of optimal aeration process conditions that results in specific microaerophilic conditions required by S. stipitis is the main challenge for ethanol production. The present study aimed to improve the ethanol production from HSSL by S. stipitis through a two-stage aeration fermentation. Experiments with controlled dissolved oxygen tension (DOT) in the first stage and oxygen restriction in the second stage were carried out. The best results were obtained with DOT control at 50% in the first stage, where the increase of oxygen availability provided faster growth and higher biomass yield, and no oxygen supply with an agitation rate of 250 rpm, in the second stage allowed a successful induction of ethanol production. Fermentation using 60% of HSSL (v/v) as substrate for S. stipitis provided a maximum specific growth rate of 0.07 h−1, an ethanol productivity of 0.04 g L h−1 and an ethanol yield of 0.39 g g−1, respectively. This work showed a successful two-stage aeration strategy as a promising aeration alternative for bioethanol production from HSSL by S. stipitis. Full article
(This article belongs to the Special Issue Microbial Production of Added-value Products from Renewable Resources)
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Open AccessArticle Catalytic Effect of Functional and Fe Composite Biochars on Biofuel and Biochemical Derived from the Pyrolysis of Green Marine Biomass
Fermentation 2018, 4(4), 96; https://doi.org/10.3390/fermentation4040096
Received: 20 September 2018 / Revised: 29 October 2018 / Accepted: 8 November 2018 / Published: 17 November 2018
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Abstract
This study investigated the behavior of two types of modified biochar (functional and iron composite biochars) as a catalyst regarding their surface chemistry and morphological properties and their effects on bio-product derived from pyrolysis of Cladophora glomerata (C. glomerata) macroalagae. Two
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This study investigated the behavior of two types of modified biochar (functional and iron composite biochars) as a catalyst regarding their surface chemistry and morphological properties and their effects on bio-product derived from pyrolysis of Cladophora glomerata (C. glomerata) macroalagae. Two catalytic pyrolysis experiments were conducted in 25 mL slow pyrolysis reactor in the presence of biochar-based catalysts at the temperature of 500 °C. For functional biochar, no clear effect on biogas production was observed, whereas iron composite biochar increased the hydrogen content by 7.99 mml/g algae. Iron composite biochar with a 3D network structure demonstrated remarkable catalytic behaviors (especially toward hydrogen production) due to its wonderful surface area, high dispersion of iron particles and particular structures and compositions. The biochar derived marine biomass and treatment process developed here could provide a promising path for the low-cost, efficient, renewable and environmental friendly catalysts. Full article
(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)
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Open AccessArticle Assessment of Volatile Compounds Evolution, Antioxidant Activity, and Total Phenolics Content during Cold Storage of Pomegranate Beverage Fermented by Lactobacillus paracasei K5
Fermentation 2018, 4(4), 95; https://doi.org/10.3390/fermentation4040095
Received: 12 October 2018 / Revised: 7 November 2018 / Accepted: 12 November 2018 / Published: 15 November 2018
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Abstract
A recently isolate from feta type cheese, potential probiotic strain Lactobacillus paracasei K5, was applied for pomegranate juice (Punica granutum L.) fermentation. Fermentations were carried out for 24 h followed by the storage of pomegranate juices at 4 °C for 4 weeks.
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A recently isolate from feta type cheese, potential probiotic strain Lactobacillus paracasei K5, was applied for pomegranate juice (Punica granutum L.) fermentation. Fermentations were carried out for 24 h followed by the storage of pomegranate juices at 4 °C for 4 weeks. The parameters examined were a composition of volatile compounds, antioxidant activity, total phenolic content, and consumers’ acceptance. The results were encouraging showing that lactic acid fermentation enhanced the composition of volatile compounds even at the fourth week of storage. Increased antioxidant activity (151.44 mg TE/100 mL at the second week) and total phenolics content (285 mg GAE/100 mL at the third week) were observed for all the storage times compared to the initial pomegranate beverage. The fermented pomegranate beverage received better scores for the last 3 weeks of cold storage compared to the non-fermented one. Likewise, L. paracasei K5 was proved to be suitable for the production of functional pomegranate beverages with enhanced aromatic characteristics and high nutritional value. Full article
(This article belongs to the Special Issue Probiotics and Prebiotics: New Knowledge)
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Open AccessReview The Yeast Torulaspora delbrueckii: An Interesting But Difficult-To-Use Tool for Winemaking
Fermentation 2018, 4(4), 94; https://doi.org/10.3390/fermentation4040094
Received: 27 September 2018 / Revised: 8 November 2018 / Accepted: 9 November 2018 / Published: 12 November 2018
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Abstract
Torulaspora delbrueckii is probably the non-Saccharomyces yeast that is currently most used for winemaking. Multiple advantages have been claimed for it relative to conventional S. cerevisiae strains. However, many of these claimed advantages are based on results in different research studies that
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Torulaspora delbrueckii is probably the non-Saccharomyces yeast that is currently most used for winemaking. Multiple advantages have been claimed for it relative to conventional S. cerevisiae strains. However, many of these claimed advantages are based on results in different research studies that are contradictory or non-reproducible. The easiest way to explain these discrepancies is to attribute them to the possible differences in the behaviour of the different strains of this yeast that have been used in different investigations. There is much less knowledge of the physiology, genetics, and biotechnological properties of this yeast than of the conventional yeast S. cerevisiae. Therefore, it is possible that the different results that have been found in the literature are due to the variable or unpredictable behaviour of T. delbrueckii, which may depend on the environmental conditions during wine fermentation. The present review focusses on the analysis of this variable behaviour of T. delbrueckii in the elaboration of different wine types, with special emphasis on the latest proposals for industrial uses of this yeast. Full article
(This article belongs to the Special Issue Enological Repercussions of Non-Saccharomyces Species)
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Open AccessReview Harvesting of Microalgae by Flocculation
Fermentation 2018, 4(4), 93; https://doi.org/10.3390/fermentation4040093
Received: 16 October 2018 / Revised: 5 November 2018 / Accepted: 7 November 2018 / Published: 9 November 2018
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Abstract
Due to increasing demands for microalgal biomass and products originating from microalgae, large-scale production systems are necessary. However, current microalgal production technologies are not cost-effective and are hindered by various bottlenecks, one of which is the harvesting of microalgal biomass. Cell separation is
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Due to increasing demands for microalgal biomass and products originating from microalgae, large-scale production systems are necessary. However, current microalgal production technologies are not cost-effective and are hindered by various bottlenecks, one of which is the harvesting of microalgal biomass. Cell separation is difficult because of the low sedimentation velocity of microalgae, their colloidal character with repelling negative surface charges, and low biomass concentrations in culture broths; therefore, large volumes need to be processed in order to concentrate the cells. Flocculation is considered to be one of the most suitable methods for harvesting microalgal biomass. This article provides an overview of flocculation methods suitable for microalgal harvesting, their mechanisms, advantages and drawbacks. Special attention is paid to the role of surface charge in the mechanism of flocculation. The novelty of the review lies in the interconnection between the context of technological applications and physico-chemical surface phenomena. Full article
(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)
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Open AccessReview Grape and Wine Metabolomics to Develop New Insights Using Untargeted and Targeted Approaches
Fermentation 2018, 4(4), 92; https://doi.org/10.3390/fermentation4040092
Received: 28 October 2018 / Revised: 4 November 2018 / Accepted: 5 November 2018 / Published: 7 November 2018
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Abstract
Chemical analysis of grape juice and wine has been performed for over 50 years in a targeted manner to determine a limited number of compounds using Gas Chromatography, Mass-Spectrometry (GC-MS) and High Pressure Liquid Chromatography (HPLC). Therefore, it only allowed the determination of
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Chemical analysis of grape juice and wine has been performed for over 50 years in a targeted manner to determine a limited number of compounds using Gas Chromatography, Mass-Spectrometry (GC-MS) and High Pressure Liquid Chromatography (HPLC). Therefore, it only allowed the determination of metabolites that are present in high concentration, including major sugars, amino acids and some important carboxylic acids. Thus, the roles of many significant but less concentrated metabolites during wine making process are still not known. This is where metabolomics shows its enormous potential, mainly because of its capability in analyzing over 1000 metabolites in a single run due to the recent advancements of high resolution and sensitive analytical instruments. Metabolomics has predominantly been adopted by many wine scientists as a hypothesis-generating tool in an unbiased and non-targeted way to address various issues, including characterization of geographical origin (terroir) and wine yeast metabolic traits, determination of biomarkers for aroma compounds, and the monitoring of growth developments of grape vines and grapes. The aim of this review is to explore the published literature that made use of both targeted and untargeted metabolomics to study grapes and wines and also the fermentation process. In addition, insights are also provided into many other possible avenues where metabolomics shows tremendous potential as a question-driven approach in grape and wine research. Full article
(This article belongs to the Special Issue Wine Fermentation)
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Open AccessReview Beer–The Importance of Colloidal Stability (Non-Biological Haze)
Fermentation 2018, 4(4), 91; https://doi.org/10.3390/fermentation4040091
Received: 30 September 2018 / Revised: 23 October 2018 / Accepted: 24 October 2018 / Published: 2 November 2018
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Abstract
Today’s beer differs in many ways from the original hazy brew made from grains and water left in the sun to ferment. The development of brewing procedures introduced filtration and colloidal stabilization as key elements in beer preservation and stability. Colloidal stability of
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Today’s beer differs in many ways from the original hazy brew made from grains and water left in the sun to ferment. The development of brewing procedures introduced filtration and colloidal stabilization as key elements in beer preservation and stability. Colloidal stability of beer is the most important factor in beer quality. Colloidal particles significantly shorten beer’s storage time, but most importantly, also influence its appearance. Colloidal stabilization involves one or more procedures that are applied at different stages during production and result in colloidal stability of the final product. Beer is considered to be colloidal stable if it can be stored for several months at 25 °C without exhibiting any changes in composition or other properties; specifically, beer has to be able to remain clear without any signs of precipitation. Since colloidal stability is of primary importance for the consumer, retail requirements have resulted in many solutions for this issue. Stabilization agents have to be reliable during the filtration and stabilization processes. Additionally, renewable agents are highly desirable. The level of colloidal stability required depends on the desired storage time and temperature after the beer has been packed. Consumers have higher and higher expectations that the industry has to follow. Full article
(This article belongs to the Special Issue Brewing & Distilling)
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Open AccessReview Fermented Foods and Beverages in Human Diet and Their Influence on Gut Microbiota and Health
Fermentation 2018, 4(4), 90; https://doi.org/10.3390/fermentation4040090
Received: 30 September 2018 / Revised: 25 October 2018 / Accepted: 26 October 2018 / Published: 28 October 2018
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Abstract
Dietary changes have accompanied the evolution of humanity and is proven to be fundamental in human evolution and well-being. Nutrition is essential for survival and as a matter of health and equilibrium of the human body. About 1/3 of the human diet is
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Dietary changes have accompanied the evolution of humanity and is proven to be fundamental in human evolution and well-being. Nutrition is essential for survival and as a matter of health and equilibrium of the human body. About 1/3 of the human diet is composed by fermented foods and beverages, which are widely distributed and consumed in different societies around the world, no matter the culture and lifestyle. Fermented foods are derived from the fermentation process of different substrates by microorganisms, and more importantly to humans, by those with beneficial characteristics, due to the positive impact on health. Food is transformed in the gut, gaining new proprieties, and increasing its value to the organism. The effects of fermented foods and beverages can be assessed by its influence at the gut microbiota level. Recent studies show the major importance of the gut microbiota role in modulating the organism homeostasis and homeorhesis. More crosslinks between health, gut microbiota and diet are being established especially in the gut–brain axis field. Therefore, the benefits of diet, in particularly of fermented foods and beverages, should be studied and pursued in order to promote a good health status. Full article
(This article belongs to the Special Issue Microbial Foods—The Science of Fermented Foods)
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Open AccessReview A Review on the Source of Lipids and Their Interactions during Beer Fermentation that Affect Beer Quality
Fermentation 2018, 4(4), 89; https://doi.org/10.3390/fermentation4040089
Received: 19 September 2018 / Revised: 17 October 2018 / Accepted: 22 October 2018 / Published: 24 October 2018
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Abstract
The presence of lipids in wort and beer are important due to their influence on yeast metabolism and beer quality. Barley lipids have long been considered to have adverse effects on beer quality where some long-chain fatty acids are associated with high flavour
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The presence of lipids in wort and beer are important due to their influence on yeast metabolism and beer quality. Barley lipids have long been considered to have adverse effects on beer quality where some long-chain fatty acids are associated with high flavour potential. In addition, beer foam stability can be influenced by the concentration of lipids as well as other factors such as hop acids (e.g., iso-α-acids), proteins, polysaccharides and the presence of metal ions (e.g., nickel). Lipids can also influence yeast protease activity as well as the production of ethanol. This review provides an overview of the effect of climate change on the chemical composition of barley in relation to lipids and the influence of lipids in the process of this raw material in order to produce beer. Full article
(This article belongs to the Special Issue Brewing & Distilling)
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Open AccessArticle Removal of Bacterial Contamination from Bioethanol Fermentation System Using Membrane Bioreactor
Fermentation 2018, 4(4), 88; https://doi.org/10.3390/fermentation4040088
Received: 25 September 2018 / Revised: 12 October 2018 / Accepted: 16 October 2018 / Published: 18 October 2018
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Abstract
A major issue hindering efficient industrial ethanol fermentation from sugar-based feedstock is excessive unwanted bacterial contamination. In industrial scale fermentation, reaching complete sterility is costly, laborious, and difficult to sustain in long-term operation. A physical selective separation of a co-culture of Saccharomyces cerevisiae
[...] Read more.
A major issue hindering efficient industrial ethanol fermentation from sugar-based feedstock is excessive unwanted bacterial contamination. In industrial scale fermentation, reaching complete sterility is costly, laborious, and difficult to sustain in long-term operation. A physical selective separation of a co-culture of Saccharomyces cerevisiae and an Enterobacter cloacae complex from a buffer solution and fermentation media at dilution rates of 0.1–1 1/h were examined using an immersed membrane bioreactor (iMBR). The effect of the presence of yeast, inoculum size, membrane pore size, and surface area, backwashing and dilution rate on bacteria removal were assessed by evaluating changes in the filtration conditions, medium turbidity, and concentration of compounds and cell biomass. The results showed that using the iMBR with dilution rate of 0.5 1/h results in successful removal of 93% of contaminating bacteria in the single culture and nearly complete bacteria decontamination in yeast-bacteria co-culture. During continuous fermentation, application of lower permeate fluxes provided a stable filtration of the mixed culture with enhanced bacteria washout. This physical selective separation of bacteria from yeast can enhance final ethanol quality and yields, process profitability, yeast metabolic activity, and decrease downstream processing costs. Full article
(This article belongs to the Special Issue Ethanol and Value-Added Co-Products)
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Open AccessArticle Soaking in Aqueous Ammonia (SAA) Pretreatment of Whole Corn Kernels for Cellulosic Ethanol Production from the Fiber Fractions
Fermentation 2018, 4(4), 87; https://doi.org/10.3390/fermentation4040087
Received: 4 September 2018 / Revised: 11 October 2018 / Accepted: 12 October 2018 / Published: 16 October 2018
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Abstract
Corn fiber is a co-product of commercial ethanol dry-grind plants, which is processed into distillers dried grains with solubles (DDGS) and used as animal feed, yet it holds high potential to be used as feedstock for additional ethanol production. Due to the tight
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Corn fiber is a co-product of commercial ethanol dry-grind plants, which is processed into distillers dried grains with solubles (DDGS) and used as animal feed, yet it holds high potential to be used as feedstock for additional ethanol production. Due to the tight structural make-up of corn fiber, a pretreatment step is necessary to make the cellulose and hemicellulose polymers in the solid fibrous matrix more accessible to the hydrolytic enzymes. A pretreatment process was developed in which whole corn kernels were soaked in aqueous solutions of 2.5, 5.0, 7.5, and 10.0 wt% ammonia at 105 °C for 24 h. The pretreated corn then was subjected to a conventional mashing procedure and subsequent ethanol fermentation using a commercial strain of natural Saccharomyces cerevisiae with addition of a commercial cellulase. Pretreatment of the corn with 7.5 wt% ammonia solution plus cellulase addition gave the highest ethanol production, which improved the yield in fermentation using 25 wt% solid from 334 g ethanol/kg corn obtained in the control (no pretreatment and no cellulase addition) to 379 g ethanol/kg corn (a 14% increase). The process developed can potentially be implemented in existing dry-grind ethanol facilities as a “bolt-on” process for additional ethanol production from corn fiber, and this additional ethanol can then qualify as “cellulosic ethanol” by the Environmental Protection Agency’s (EPA’s) Renewable Fuels Standard and thereby receive RINs (Renewable Identification Numbers). Full article
(This article belongs to the Special Issue Ethanol and Value-Added Co-Products)
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Open AccessFeature PaperArticle Co-Culture of Filamentous Feed-Grade Fungi and Microalgae as an Alternative to Increase Feeding Value of Ethanol Coproducts
Fermentation 2018, 4(4), 86; https://doi.org/10.3390/fermentation4040086
Received: 24 September 2018 / Revised: 5 October 2018 / Accepted: 9 October 2018 / Published: 11 October 2018
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Abstract
Distiller’s grains, an important commodity in the feed and food chains, are currently underdosed in rations due to several factors, mainly nutrient imbalance. This study aimed to increase the linoleic acid content in distiller’s grains and decrease the excess nutrients in stillage water
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Distiller’s grains, an important commodity in the feed and food chains, are currently underdosed in rations due to several factors, mainly nutrient imbalance. This study aimed to increase the linoleic acid content in distiller’s grains and decrease the excess nutrients in stillage water by the use of an artificial lichen, composed of fungi, algae, and a supporting matrix. A maximum concentration of 46.25% of linoleic acid in distiller’s grains was achieved with a combination of Mucor indicus and Chlorella vulgaris using corn-to-ethanol whole stillage as substrate. Microbial hydrolytic enzymes during fermentation were able to decrease the solids in whole stillage. Nitrogen depletion by microalgal uptake causes lipid-formation stress to Mucor indicus cells, increasing linoleic acid production to about 49% of the total lipids, potentially decreasing costs in the animal feed. The culture supernatant can potentially be recycled as process water to the ethanol fermentation tank, and enhanced distiller’s grains can replace animal-specific diets. This would reduce exogenous enzyme use and supplementation of unsaturated fatty acids from other sources. Full article
(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)
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Open AccessReview The Multiple and Versatile Roles of Aureobasidium pullulans in the Vitivinicultural Sector
Fermentation 2018, 4(4), 85; https://doi.org/10.3390/fermentation4040085
Received: 27 August 2018 / Revised: 2 October 2018 / Accepted: 4 October 2018 / Published: 9 October 2018
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Abstract
The saprophytic yeast-like fungus Aureobasidium pullulans has been well documented for over 60 years in the microbiological literature. It is ubiquitous in distribution, being found in a variety of environments (plant surfaces, soil, water, rock surfaces and manmade surfaces), and with a worldwide
[...] Read more.
The saprophytic yeast-like fungus Aureobasidium pullulans has been well documented for over 60 years in the microbiological literature. It is ubiquitous in distribution, being found in a variety of environments (plant surfaces, soil, water, rock surfaces and manmade surfaces), and with a worldwide distribution from cold to warm climates and wet/humid regions to arid ones. Isolates and strains of A. pullulans produce a wide range of natural products well documented in the international literature and which have been regarded as safe for biotechnological and environmental applications. Showing antagonistic activity against plant pathogens (especially post-harvest pathogens) is one of the major applications currently in agriculture of the fungus, with nutrient and space competition, production of volatile organic compounds, and production of hydrolytic enzymes and antimicrobial compounds (antibacterial and antifungal). The fungus also shows a positive role on mycotoxin biocontrol through various modes, with the most striking being that of binding and/or absorption. A. pullulans strains have been reported to produce very useful industrial enzymes, such as β-glucosidase, amylases, cellulases, lipases, proteases, xylanases and mannanases. Pullulan (poly-α-1,6-maltotriose biopolymer) is an A. pullulans trademark product with significant properties and biotechnological applications in the food, cosmetic and pharmaceutical industries. Poly (β-l-malic acid), or PMA, which is a natural biopolyester, and liamocins, a group of produced heavy oils and siderophores, are among other valuable compounds detected that are of possible biotechnological use. The fungus also shows a potential single-cell protein source capacity with high levels of nucleic acid components and essential amino acids, but this remains to be further explored. Last but not least, the fungus has shown very good biocontrol against aerial plant pathogens. All these properties are of major interest in the vitivinicultural sector and are thoroughly reviewed under this prism, concluding on the importance that A. pullulans may have if used at both vineyard and winery levels. This extensive array of properties provides excellent tools for the viticulturist/farmer as well as for the oenologist to combat problems in the field and create a high-quality wine. Full article
(This article belongs to the Special Issue Enological Repercussions of Non-Saccharomyces Species)
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Open AccessArticle Wineinformatics: Regression on the Grade and Price of Wines through Their Sensory Attributes
Fermentation 2018, 4(4), 84; https://doi.org/10.3390/fermentation4040084
Received: 4 September 2018 / Revised: 22 September 2018 / Accepted: 24 September 2018 / Published: 29 September 2018
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Abstract
Wineinformatics is a field that uses machine-learning and data-mining techniques to glean useful information from wine. In this work, attributes extracted from a large dataset of over 100,000 wine reviews are used to make predictions on two variables: quality based on a “100-point
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Wineinformatics is a field that uses machine-learning and data-mining techniques to glean useful information from wine. In this work, attributes extracted from a large dataset of over 100,000 wine reviews are used to make predictions on two variables: quality based on a “100-point scale”, and price per 750 mL bottle. These predictions were built using support vector regression. Several evaluation metrics were used for model evaluation. In addition, these regression models were compared to classification accuracies achieved in a prior work. When regression was used for classification, the results were somewhat poor; however, this was expected since the main purpose of the regression was not to classify the wines. Therefore, this paper also compares the advantages and disadvantages of both classification and regression. Regression models can successfully predict within a few points of the correct grade of a wine. On average, the model was only 1.6 points away from the actual grade and off by about $13 per bottle of wine. To the best of our knowledge, this is the first work to use a large-scale dataset of wine reviews to perform regression predictions on grade and price. Full article
(This article belongs to the Special Issue Bioprocess and Fermentation Monitoring)
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Open AccessReview Discovering the Health Promoting Potential of Fermented Papaya Preparation—Its Future Perspectives for the Dietary Management of Oxidative Stress During Diabetes
Fermentation 2018, 4(4), 83; https://doi.org/10.3390/fermentation4040083
Received: 24 July 2018 / Revised: 4 September 2018 / Accepted: 27 September 2018 / Published: 28 September 2018
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Abstract
The simplistic morphological characteristics of Carica papaya fruit or “pawpaw” should not be the cause for underestimating its potential as a nutraceutical. The market for papaya has been expanding at a staggering rate, partly due to its applicability as a biofortified product, but
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The simplistic morphological characteristics of Carica papaya fruit or “pawpaw” should not be the cause for underestimating its potential as a nutraceutical. The market for papaya has been expanding at a staggering rate, partly due to its applicability as a biofortified product, but also due to its phytochemical properties and traditional health benefits. Papaya or formulations of fermented papaya promotion (FPP) display effective free radical scavenging abilities thought to be influenced by its phenolic, carotenoid, flavonoid, or amino acid profile. The antioxidant properties of FPP have been extensively reported in literature to potently target a broad spectrum of free radical-induced diseases ranging from neurological impairments, such as senile dementia, to systemic diseases, to its interference at the cellular level and the support of normal biological ageing processes. FPP has thus been extensively investigated for its ability to exert cellular protective effects and reduce oxidative stress via the mitigation of genetic damage, reduction of lipid peroxidation, and enzymatic inactivation in specific diseases. The focus of this review is to appraise the potential of oxidative stress reduction strategies of FPP and discuss its holistic approach in disease prevention and management, with a particular focus on diabetes and cancer. However, with the current lack of information surrounding its mechanism of action, this review wishes to set the stage and aspire researchers to more profoundly investigate molecular pathways related to how FPP can unequivocally contribute to wellness in an aging population. Full article
(This article belongs to the Special Issue Safety and Microbiological Quality)
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Open AccessArticle Wineinformatics: A Quantitative Analysis of Wine Reviewers
Fermentation 2018, 4(4), 82; https://doi.org/10.3390/fermentation4040082
Received: 31 July 2018 / Revised: 14 September 2018 / Accepted: 17 September 2018 / Published: 25 September 2018
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Abstract
Data Science is a successful study that incorporates varying techniques and theories from distinct fields including Mathematics, Computer Science, Economics, Business and domain knowledge. Among all components in data science, domain knowledge is the key to create high quality data products by data
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Data Science is a successful study that incorporates varying techniques and theories from distinct fields including Mathematics, Computer Science, Economics, Business and domain knowledge. Among all components in data science, domain knowledge is the key to create high quality data products by data scientists. Wineinformatics is a new data science application that uses wine as the domain knowledge and incorporates data science and wine related datasets, including physicochemical laboratory data and wine reviews. This paper produces a brand-new dataset that contains more than 100,000 wine reviews made available by the Computational Wine Wheel. This dataset is then used to quantitatively evaluate the consistency of the Wine Spectator and all of its major reviewers through both white-box and black-box classification algorithms. Wine Spectator reviewers receive more than 87% accuracy when evaluated with the SVM method. This result supports Wine Spectator’s prestigious standing in the wine industry. Full article
(This article belongs to the Special Issue Bioprocess and Fermentation Monitoring)
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Open AccessArticle Intensive Production of Carboxylic Acids Using C. butyricum in a Membrane Bioreactor (MBR)
Fermentation 2018, 4(4), 81; https://doi.org/10.3390/fermentation4040081
Received: 13 August 2018 / Revised: 18 September 2018 / Accepted: 19 September 2018 / Published: 21 September 2018
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Abstract
This work reports on the use of a bench-scale chemostat (CSTR) in continuous mode and of a pilot-scale membrane bioreactor (MBR) in fed-batch mode to intensively produce acetic and butyric acids using C. butyricum grown on synthetic media. These studies were then used
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This work reports on the use of a bench-scale chemostat (CSTR) in continuous mode and of a pilot-scale membrane bioreactor (MBR) in fed-batch mode to intensively produce acetic and butyric acids using C. butyricum grown on synthetic media. These studies were then used to perform a cost estimation study of the MBR system to assess the potential economic impact of this proposed methodology, regarding the production of carboxylic acids. The MBR system was found to be highly productive, reaching 37.88 g L−1 h−1 of acetic and 14.44 g L−1 h−1 of volumetric cell productivity, favoring acetic acid production over butyric acid at a ratio of 3 moles to 1. The cost of preparation and production of carboxylic acid using this system was found to be 0.0062 £PS/kg with up to 99% carbon recovery. Full article
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