Fermentation, Volume 10, Issue 9 (September 2024) – 54 articles

Sonoporation stimulates cell growth as it improves the permeability of the membrane and increases the uptake of impermeable molecules in the extracellular matrix. We evaluated the effects of substrates (whey, whole, and skim milk) and ultrasonic treatments (ultrasonication and thermosonication) on the antioxidant activity (AA) of water-soluble kefir postbiotics (WSKPs). The samples were evaluated in terms of antioxidant activity (ABTS, DPPH, FRAP, and ORAC), water-soluble protein content, proteolysis (SDS-PAGE profiles), and cell membrane permeability. The levels of AA in all WSKPs depended on the substrate and method of obtaining them. However, the WSKPs from whey had higher antioxidant activity with DPPH (11.11 mg TE/100 mL), ABTS (12.77 mg TE/100 mL), and FRAP (5.18 mg TE/100 mL). Also, the WSKPs from whey had the highest values for water-soluble protein (1.45–1.32 mg/mL) and proteolysis degree and the lowest percentage of dead cells (11.4–28%). These results suggest that the production of WSKPs from whey might add value to whey production. Furthermore, WSKPs have potential as a functional ingredient in the production of beverages or foods with antioxidant activity. Full article

Lactobacillus is a recognized probiotic and has been widely used in food and medicine. As a new type of low-temperature resistant Lactobacillus, the fermentation products of Dellaglioa algida have multiple physiological activities. This study focuses on the exopolysaccharide (EPS) produced by Dellaglioa algida. The composition of the EPS is analyzed by FTIR, UV, GPC, HPLC, NMR, and SEM, and its antioxidant and immune activities are explored. The experimental results show that the EPS is a polymer composed of nine monosaccharides such as rhamnose, glucose, and mannose, connected by $\alpha$- and $\beta$-glycosidic bonds, with an average molecular weight of $2.163\times {10}^4$ Da. When the EPS concentration reaches 100 μg/mL, the scavenging activities of DPPH and ABTS⁺ are 60.0% and 51.2%, respectively. The EPS promotes the secretion of NO by regulating the iNOS/NO pathway, reduces oxidative damage, and reduces the secretion of inflammatory factors such as IL-6, IL-1$\beta$, and TNF-$\alpha$, and downregulates the mRNA expression of inflammatory factors, thereby alleviating the cell inflammation stimulated by the cold-resistant bacteria Pseudomonas fluorescens and Pseudomonas fragi. By virtue of these properties, the EPS produced by Dellaglioa algida fermentation has the potential to act as an antioxidant and immunomodulator. Full article

Developing recombinant Saccharomyces cerevisiae strains capable of transporting and fermenting cellobiose directly is a promising strategy for second-generation ethanol production from lignocellulosic biomass. In this study, we cloned and expressed in the S. cerevisiae CEN.PK2-1C strain an intracellular β-glucosidase (SpBGL7) from Spathaspora passalidarum and co-expressed the cellobiose transporter SiHXT2.4 from Scheffersomyces illinoinensis, and two putative transporters, one from Candida tropicalis (CtCBT1 gene), and one from Meyerozyma guilliermondii (MgCBT2 gene). While all three transporters allowed cell growth on cellobiose, only the MgCBT2 permease allowed cellobiose fermentation, although cellobiose consumption was incomplete. The analysis of the β-glucosidase and transport activities revealed that the cells stopped consuming cellobiose due to a drop in the transport activity. Since ubiquitinylation of lysine residues at the N- or C-terminal domains of the permease are involved in the endocytosis and degradation of sugar transporters, we constructed truncated versions of the permease lacking lysine residues at the C-terminal domain (MgCBT2ΔC), and at both the C- and N-terminal domain (MgCBT2ΔNΔC) and co-expressed these permeases with the SpBGL7 β-glucosidase in an industrial strain. While the strain harboring the MgCBT2ΔC transporter continued to produce incomplete cellobiose fermentations as the wild-type MgCBT2 permease, the strain with the MgCBT2ΔNΔC permease was able to consume and ferment all the cellobiose present in the medium. Thus, our results highlight the importance of expressing cellobiose transporters lacking lysine at the N- and C-terminal domains for efficient cellobiose fermentation by recombinant S. cerevisiae. Full article

Hygiene practices are crucial for the production of fermented products, as they affect both product quality and safety. Fermented products, including dairy-based such as kefir, kombucha, and traditional ethnic drinks, rely on beneficial microbes. However, poor cleanliness might introduce dangerous microorganisms, jeopardizing customer health and product stability. This study aims to discuss the key hygiene measures required for safe and high-quality drinkable dairy-based and plant-based fermented product production and to avoid cross-contamination, fermentation vessels, utensils, and storage containers should be cleaned and sterilized regularly. Personal hygiene for workers is also critical, including adequate handwashing, the use of protective equipment, and hygiene protocol training. Another key part of industrial facility management is environmental control and furthermore, adopting Hazard Analysis and Critical Control Points (HACCP) systems allows for the systematic identification and mitigation of production-related risks. Regular microbiological examination of items and surfaces helps to ensure that hygiene methods are effective and that the products fulfill safety requirements. Therefore, strict hygiene measures must be followed when creating fermented drinks to provide safe, high-quality products. Such procedures not only protect consumer health, but also improve product shelf life and sensory properties, increasing consumer trust and satisfaction. Full article

p-Cymene (p-C) [1-methyl-4-(1-methylethyl)-benzene] is a monoterpene found in a variety of plants and has several biological activities, including antioxidant, anti-inflammatory, antimicrobial, and anticancer properties. This paper explores the microbial fermentation pathways involved in the biosynthesis of p-C, with an emphasis on its potential as a therapeutic agent. Through microbial and biochemical processes, p-C can be produced using renewable precursors such as limonene and 1,8-cineole. Recent advances in fermentation technology have enhanced the efficiency of p-C production, highlighting its role in various industries. Additionally, this paper reviews the antimicrobial bioactivity of p-C, focusing on its ability to inhibit pathogens and modulate immune responses. The integration of microbial biosynthesis and fermentation methods offers a sustainable approach to producing p-C for applications in the perfume, cosmetics, food, and pharmaceutical sectors. Understanding these biosynthetic pathways is crucial for advancing the use of p-C as a bio-based chemical with therapeutic potential. In particular, p-C inhibits the expression of cytokine signal 3 in intestinal inflammation and modulates antioxidant and immunomodulatory systems to protect barrier cells and maintain the mucus layer. Full article

This work aimed to study the effect of Camellia sinensis extract (CSExt) as a particular growth promoter of Lactiplantibacillus plantarum (LP) in batch and continuous production processes. Growth conditions were 1% (v/v) inoculum, pH_C = 6.5, 1% of dissolved oxygen (D.O.), 37 °C, and 150 rpm in a 0.2 L bioreactor using a commercial MRS broth (de Man, Rogosa, and Sharpe) and 1% (v/v) or 10% (v/v) CSExt according to the experimental design. In batch experiments, the maximum specific growth rate and the affinity constant increased with the increase in CSExt. In continuous culture, biomass production increased significantly with the addition of 1% (w/v) CSExt at 0.15 (1/h). Kinetic parameters adjusted were similar to those reported in the literature. Substrate affinity and the specific growth rate increased significantly in the presence of CSExt in batch and continuous cultures. Based on the results, prebiotics from plant extracts may function as growth promoters in specific physiological stages. This is the first report showing the change in kinetic parameters of a probiotic strain growing in crude plant extracts. Full article

Allium genus vegetables have significant functional effects on health. In recent years, consumer demand for black forms of these vegetables, produced from fresh Alliums through spontaneous fermentation at high temperature and humidity, has increased, while their functional effects have yet to be fully elucidated. The aim of this study was to compare the antioxidant capacity and total phenol content of various Allium vegetables (yellow onion, red onion, white onion, and garlic) in both their raw and black (fermented) forms. For the production of black onions and black garlic, unpeeled raw forms of these vegetables were kept at 75 °C and 90% humidity for 9 days. Afterward, fresh and fermented samples were lyophilized, dried, and evaluated for total phenol content by the Folin–Ciocalteu method and for antioxidant activity by the ABTS and DPPH methods. The total phenol content increased significantly in all samples after fermentation (p < 0.05), with the highest increases observed in garlic (216%), while the increases in onion species ranged between 44.6% and 118.3%. The increase in antioxidant capacity was also significant in all samples (p < 0.05) and was higher in garlic than in onions. Changes in antioxidant capacity and total phenol content indicate that fermentation improves the nutritional quality of these vegetables. Full article

During the anaerobic digestion (AD) of fruit and vegetable waste (FVW), excessive particle size reduction can lead to the overproduction and inhibition of methanogenic microorganisms. This paper presents an in-depth analysis through experimental assays, modeling, and response surface analysis of the effect of particle size on methane production. A simple model was proposed considering the inhibition of the growth of methanogenic microorganisms and surface-based hydrolysis kinetics. The model parameters were estimated using experimental data from batch systems fed with FVW of varying particle sizes (ranging from 1.8 to 1000 μm). Response surface methodology establishes a statistical model for estimating methane production based on particle size and concentration. Numerical and statistical analyses were conducted using Matlab R2024a and Minitab 24 software. A model with an R² of 0.89 was obtained, which determined an optimal concentration of 8.2 $\mathrm{k}\mathrm{g}·{\mathrm{m}}^{-3}$ and a particle size of 742.3 $\mathsf{\mu }\mathrm{m}$, yielding a methane production of 303.3 ${\mathrm{m}}^3·\mathrm{k}{\mathrm{g}}^{-1} \mathrm{V}\mathrm{S}$, similar to the experimentally obtained range of 300.95 to 316.7 ${\mathrm{m}}^3·\mathrm{k}{\mathrm{g}}^{-1} \mathrm{V}\mathrm{S}$. Full article

The exploration of microbial genetic resources for the production of fFen-flavor Baijiu has not only enriched the microbial library for baijiu production but has also laid the foundation for process improvement and strain optimization in baijiu brewing. In this study, a total of 177 fungal isolates were screened, including Saccharomyces cerevisiae, non-Saccharomyces cerevisiae, molds, and some pathogenic bacteria. Among them, Saccharomyces cerevisiae was the most abundant with 119 isolates, playing a major role in the fermentation of baijiu production. A total of 148 bacterial isolates were obtained from the fermentation mash samples, showing greater diversity compared to fungi. Bacillus species were the most abundant, with 94 isolates. Bacillus licheniformis, in particular, can produce a rich enzymatic system and flavor precursors, making it an important contributor to the sensory quality of baijiu. Lactic acid bacteria were the second most abundant, with 16 isolates. Additionally, five pathogenic fungal species were identified, including Candida pelliculosa, Candida lusitaniae, Fusarium oxysporum, Fusarium solani and Talaromyces marneffei. Six pathogenic bacterial species were also isolated, namely Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus xylosus, Moraxella osloensis, Actinomyces meyeri and Stenotrophomonas maltophilia. Finally, two strains of high acetate ethyl ester-producing yeast and lactate-degrading bacteria with good tolerance to temperature, pH, and ethanol concentration were identified as Saccharomyces cerevisiae and Bacillus licheniformis, respectively. Full article

Hemp seed protein (HSP), a by-product of hemp oil processing, was converted into a functional protein ingredient enriched with γ-aminobutyric acid (GABA) and peptides through a two-step microbial fermentation process. To enhance peptide and free amino acid production from HSP, it was hydrolyzed using alkaline protease produced by Bacillus subtilis HA. The HSP was hydrolyzed at a degree of 40% at 55 °C for 24 h, yielding a pH of 6.55, an acidity of 1.22%, and 205.45 mg% tyrosine equivalents. This process resulted in the production of low molecular-weight peptides. (<5000 Da) The total amino acid content and branched-chain amino acids (leucine, isoleucine, and valine) were 6.78 mg/g and 1.47 mg/g. Subsequently, the production of γ-aminobutyric acid (GABA) in the HSP hydrolysate was optimized through co-fermentation with lactic acid bacteria in the presence of 5% MSG at 30 °C for 5 days. The serial co-fermented HSP hydrolysate exhibited a GABA content of 33.98 mg/g and a viable bacterial count of 9.51 log CFU/mL for Lb. plantarum KS2020. This serial co-fermentation process, combining proteolysis and lactic acid fermentation, not only increased the peptide content but also promoted GABA accumulation, positioning HSP hydrolysate as a promising candidate for functional foods with potential health benefits. Full article

Mead is a fermented alcoholic beverage produced from a diluted solution of honey and yeast activity. The objectives of this study were to produce a potentially probiotic mead through mixed fermentation by Saccharomyces cerevisiae var. boulardii and kombucha microorganisms and to evaluate fermentation kinetics, microbial cell survival and their in vitro resistance to simulated gastrointestinal transit, color parameters and the phenolic and antioxidant potential of the product. The main results of this study show that in order to develop a potentially probiotic mead utilizing the mixed fermentation of S. boulardii and kombucha microorganisms, the best condition was a concentration of 25 mL/L (v/v) of kombucha and 0.75 g/L (w/v) of S. boulardii with fermentation for 9 days at a temperature of 25 °C. In addition, at the end of fermentation, mead with kombucha and S. boulardii presented physicochemical characteristics with a pH of 3.48, 0.67% total acidity, 18.76 °Brix soluble solids and 4.77% alcohol content. The S. boulardii and lactic acid bacteria (LAB) present in the mead survived conditions reproducing those of the gastrointestinal tract, with counts of more than 6 Log₁₀ CFU/mL for both microorganisms after the intestinal phase. In the color analysis, the mead with kombucha and S. boulardii had a yellow color with the b* parameter corresponding to 35.93, luminosity (L*) equal to 76.09 and 1.82 for a*. In addition, the mead we produced contains quantities of phenolics and antioxidants. In conclusion, kombucha and S. boulardii are presented as alternative microbial sources for obtaining potentially probiotic mead. Full article

The packed-bed bioreactor is among the most promising reactor configurations for solid-state fermentation. However, the bed thickness poses several limitations involving mass and energy transfer, heat generation, and the homogeneity of the material, hampering its development at the industrial scale. Fungi are among the most promising microorganisms used in this configuration; however, only polypropylene bags and trays are used at the industrial scale. In this work, Beauveria bassiana is used to demonstrate the potential of solid-state fermentation for conidia production. A scale-up from 0.5 L to 22 L is presented, starting with substrate selection, optimization via design of experiments and 22 L batches. The optimized parameters were 70% moisture, 6.5 × 10⁶ conidia mL⁻¹ inoculum concentration, 20 mL min⁻¹ airflow, 25 °C; temperature, and 40 C/N ratio. After optimization, beer draff was chosen as the preferred substrate for scale-up. Air-filled porosity was found to be the key parameter in fungal solid-state fermentation scale-up, establishing values of around 80% as necessary for fungal conidia production when working in a 22 L packed-bed bioreactor. When compared with the tray bioreactor, the packed bed obtained higher conidia production due to its better use of the total reactor volume. Our study harnesses the potential of the packed-bed bioreactor and serves as a base for further scale-up to industrial scale. Full article

Many studies have found that salted radishes offer various health benefits, such as enhancing antioxidant levels and increasing GABA. This study fermented a mixture of 20-year-old salted radishes (20-S. radishes), 2-year-old salted radishes (2-S. radishes), 20-year-old salted radishes combined with fresh radishes (R + 20-radishes), and fresh radishes with eight whole grains fermentation as a starter (EGS) for 8 weeks. EGS was derived from the saccharified fermentation of millet, wheat, sorghum, black rice, buckwheat, pearled rice, black glutinous rice, and quinoa, serving as a carbon source for microorganisms and replacing the traditional sugar-based fermentation method. During the fermentation process, the bacterial count of the 20-year-old salted radishes significantly increased to 11.08 ± 0.03 log CFU/mL, which was much higher than the other three groups. Pichia manshurica LYC1722 was identified in all four groups after isolation. After 8 weeks of fermentation, 20-S. radishes showed the highest concentrations of gamma-aminobutyric acid (GABA) and glucuronic acid in functional components, at 18.40 ± 0.69 ppm and 14,162.84 ± 48.22 ppm, respectively. In terms of antioxidant components, 20-S. radishes exhibited a total phenolic content (TPC) and total flavonoid content (TFC) of 0.81 ± 0.01 mg/mL and 42.78 ± 0.60 mg/L, respectively. Regarding antioxidant capability, 20-S. radishes displayed ABTS radical scavenging activity and DPPH radical scavenging activity at 184.42 ± 0.28 μg/mL and 9.13 ± 0.28 μg/mL, respectively. These values were the highest among the four groups evaluated. Fresh radishes exhibited the highest angiotensin-converting enzyme (ACE) inhibition after fermentation among the four groups, reaching 69.04 ± 2.82%, slightly higher than 20-S. radishes. These results show that 20-S. radishes are expected to become a novel health beverage in the future. Full article

Understanding drug release in the colon is fundamental to developing efficient treatments for colon-related diseases, while unraveling the relationship between the colonic microbiota and excipients is crucial to unveiling the effect of biomaterials on the release of drugs. In this contribution, the bio-release of ibuprofen (encapsulated in acetylated and palmitoylated agave fructans) was evaluated by fermentation with lactic acid bacteria in simulated physicochemical (pH and temperature) colon conditions. It was observed that the size of the acyl chain (1 in acetyl and 15 in palmitoyl) was critical both in the growth of the microorganisms and in the release of the drug. For example, both the bacterial growth and the release of ibuprofen were more favored with acetylated fructan microspheres. Among the microorganisms evaluated, Bifidobacterium adolescentis and Lactobacillus brevis showed great potential as probiotics useful to release drugs from modified fructans. The production of short-chain fatty acids (lactic, acetic, and propionic acids) in the course of fermentations was also determined, since such molecules have a positive effect both on colon-related diseases and on the regulation of the intestinal microbiota. It was found that a higher concentration of acetate is related to a lower growth of bacteria and less release of ibuprofen. Full article

Intercropping systems and exogenous microorganism additives are recognized for their potential to influence silage fermentation and quality. This study aims to evaluate the impacts of maize–lablab bean intercropping and lactic acid bacteria (LAB) additives on silage yield, nutritional quality, and economic profitability. A randomized block design was employed with two cropping patterns—maize monocrop (M) and maize–lablab intercrop (ML)—and five additive treatments: No additives (CK), and varying ratios of Lactobacillus Plantarum (LP) and Lactobacillus Buchneri (LB), T1 (100% LP), T2 (9LP:LB), T3 (8LP:2LB), and T4 (100% LB). The silage was analyzed and evaluated for its nutritional quality, fermentation quality, and fermentation effect after 90 days of fermentation. ML intercropping significantly enhanced the fresh matter yields by 8.59% and crude protein content by 8.73% compared to M. From the point of view of inoculation with different lactobacilli, the pH, AA, and NH₃-N/TN were lower in the T2 and T3 treatments than in the other treatments, while LA was significantly higher. The V-score, which reflects the overall fermentation quality, was excellent across all treatments, with scores exceeding 80 points; the T2 treatment in ML silage achieved the highest score of 99.58. In addition, intercropping can increase the net income of farmers by 21.67%. In conclusion, maize–lablab intercropping combined with LAB inoculation, particularly with the T2 and T3 treatments, significantly enhances the silage quality and economic returns by reducing pH, increasing the LA content, and improving the CP levels. This study is the first to comprehensively analyze the synergistic effects of altering cropping systems and adding functional microorganisms on forage yield and fermentation quality, offering strategic insights for farms, especially mixed farms, to produce high-quality feed. We recommend adopting these methods to improve feed quality and maximize the profitability of silage production systems. Full article

Sludge alkaline fermentation liquid (AFL) is a potential carbon source for biological denitrification. However, its effectiveness is limited due to the presence of nutrients and heavy metals. In this study, acid-modified sepiolite (MSEP) was used to extract short-chain fatty acids (SCFAs) from AFL under optimized conditions and then with the prepared MSEP-AFL as a carbon source for denitrification. The optimal condition with an MSEP dosage of 1.96 g/L and pH 7.93 at 30 °C was obtained based on single-factor experiments and response surface methodology (RSM). Carbon balance revealed that 96.2% of the SCFAs, including 43.7% acetate and 23.5% propionic acid, was retained in the MSEP, demonstrating its high selectivity. The adsorption process followed the pseudo-second-order kinetic and Langmuir isothermal model, indicating dominant physical adsorption on the surface or in the fiber pores. This was further supported by the changes in the morphological features and surface properties of the MSEP. In the batch nitrate utilization experiments, the prepared MSEP-AFL was proven to be efficient as a carbon source, with a nitrate removal efficiency of 88.7% and a specific denitrification rate of 8.2 mg NOx-N/g VSS·h, which was 22% higher than that of the AFL. This was due to the establishment of a delicate “release–utilization” balance. These findings contribute to our understanding of the use of AFL for denitrification. Full article

Yeasts play an essential role in the aroma and sensory profiles of wines. Spontaneous fermentations were carried out at the newly built winery of Granxa D’Outeiro. Yeasts were isolated from must at different stages of fermentation. Colonies belonging to Saccharomyces cerevisiae were characterised at the strain level by mtDNA-RFLPs. General chemical parameters and aroma profiles of the wines were determined using official OIV methodology and GC-MS analysis, respectively. The diversity of S. cerevisiae per fermentation ranged from 5 to 13 different strains depending on the grapevine variety. Out of 24 strains, strain B was the dominant yeast in most fermentations at different proportions, but strains D, E, and H also reached up to 25% of the total population in some fermentations. The yeast diversity was higher in the Lado fermentation than in those containing Treixadura. The chemical compositions of the wines revealed differences among them, with Loureira and Albariño wines showing the highest content of volatile compounds. The evaluation of their technological properties revealed the oenological potential of some strains of S. cerevisiae. The strains showing the best scores were selected to be used in future vintages to enhance the typicality of wines in the Granxa D’Outeiro winery. Full article

The incorporation of monensin into cattle diets can significantly alter the physicochemical properties of excreted manure, potentially affecting waste management and treatment systems given the persistence of substantial concentrations of ionophores in the effluent. This study assessed the impact of monensin on the compositional characteristics of cattle manure and its implications for anaerobic digestion efficiency, with and without the separation of manure fractions across two hydraulic retention times (HRTs). Manure samples were collected from cattle fed with doses of monensin at 0, 1.8, 3.6, 5.4, and 7.2 mg per kg of dry matter intake. The HRTs investigated were 20 days (HRT20) and 30 days (HRT30). Increasing monensin inclusion in the diets resulted in a notable decrease in the quantities of total solids (TSs), volatile solids (VSs), and neutral detergent fiber (NDF) per animal per day, accompanied by an increase in lignin content and mass. Fraction separation during anaerobic digestion enhances the reduction of TSs, VSs, and NDF, thereby optimizing biogas and methane production potentials and elevating methane concentrations. The presence of monensin correlated with the reduced degradation of organic components during the anaerobic digestion process. To maximize the efficiency of the anaerobic digestion of manure from cattle diets supplemented with monensin, a 30-day HRT combined with fraction separation is recommended. This approach can enhance biogas yield and methane content, thereby improving the sustainability and efficacy of waste treatment processes. Full article

Odor emissions from animal manure present a significant environmental challenge in livestock farming, impacting air quality and farm sustainability. Traditional methods, such as chemical additives and manure treatment, can be costly, labor-intensive, and less eco-friendly. Therefore, this study investigated the effectiveness of microbial feed additives in reducing these odors. Conducted over three months in 2022 on a Korean beef cattle farm with 20 cattle, the experiment involved feeding a mixture of four microbial strains—Bacillus subtilis KNU-11, Lactobacillus acidophilus KNU-02, Lactobacillus casei KNU-12, and Saccharomyces cerevisiae KNU-06. Manure samples were collected from an experimental group (n = 9) and a control group (n = 11), with microbial community changes assessed through 16S ribosomal RNA gene amplicon sequencing. The results demonstrated significant reductions in specific odorous compounds in the experimental group compared to the control group: ammonia decreased by 64.1%, dimethyl sulfide by 81.3%, butyric acid by 84.6%, and isovaleric acid by 49.8%. Additionally, there was a notable shift in the microbiome, with an increase in the relative abundance of Ruminococcaceae and Prevotellaceae microbes associated with fiver degradation and fermentation, while the control group had higher levels of Bacteroidota and Spirochaetota, which are linked to pathogenicity. This study demonstrates that probiotics effectively alter intestinal microbiota to enhance microorganisms associated with odor mitigation, offering a promising and more sustainable approach to reducing odor emissions in livestock farming. Full article

Glucosidases are important enzyme largely used in food industry; for this reason, different research studies have been aimed at investigating new producing microorganisms and cheap growth medium that can help to minimize their production costs and time. Food by-products and wastes are considered low-cost substrates that can play an important role from the perspective of a circular economy concept. Brewer’s spent grain (BSG) is the most abundant by-product of beer production that, thanks to its chemical and nutritional composition, has recently been re-evaluated for its application in various sectors. The aim of the present study was to induce the production of β-glucosidase in Wickerhamomyces anomalus BS91 using BSG as the main component. The results obtained during our research show that BSG is an attractive by-product of beer industry that can be used for the production of glucosidase. Enzyme activity obtained using this microorganism was equal to 369.7 ± 8.0 U/mL, six time greater than that observed in conventional nutritional medium (59.0 ± 5.7 U/mL). Also, we conducted additional research concerning β-glucosidase localization, and the obtained results show that the enzyme is tightly bound to the yeast cell wall, and this can probably greatly affect its stability since it is being protected by the cell wall itself. Full article

An amylolytic industrial yeast strain named 1974-GA-temA, developed previously by our research team by coexpressing the α-amylase and glucoamylase genes, combines enzyme production, sweet potato residue (SPR) hydrolysis, and glucose fermentation into ethanol in a one-step process. This consolidated bioprocessing (CBP) method has great application potential in the commercial production of bioethanol from SPR, but important fermentation parameters should be optimized to further increase the ethanol concentration and yield. In this study, the effects of the initial fermentation pH, solid-to-liquid ratio, inoculation volume, addition of exogenous enzyme, and supplementation with metal ions were systemically investigated. Single-factor experiments revealed that the optimal pH was 4.0. In the solid-to-liquid ratio test, an increase in the solid-to-liquid ratio corresponded with a gradual increase in the ethanol concentration, peaking at 1:5. However, the ethanol yield gradually decreased, with the optimal solid-to-liquid ratio identified as 1:5. The ethanol concentration and yield reached 9.73 g/L and 5.84%, respectively. Additionally, an increase in the inoculum size resulted in increased ethanol concentration and yield, with the optimal inoculum level determined to be 10%. An ethanol concentration of 7.87 g/L was attained under these specified conditions, equating to an ethanol yield of 4.72%. Further analysis was conducted to assess the effects of exogenous cellulase, hemicellulase, and pectinase, both individually and in combination, on ethanol concentration and yield. The results indicated that pectinase had a particularly significant effect. The highest ethanol concentration was observed when all three enzymes were administered concurrently, yielding 27.27 g/L ethanol. Then, the role of metal ions in SPR fermentation was evaluated. The metal ions did not significantly affect the process, with the exception of copper ions. The addition of copper ions at a specific concentration of 0.2 g/100 g SPR increased the ethanol concentration. However, concentrations exceeding 0.2 g/100 g SPR inhibited yeast cell growth. Finally, orthogonal optimization was employed to determine the optimal combination of factors: pH, 4.0; solid-to-liquid ratio, 1:6; inoculation volume, 10%; cellulase and pectinase addition; and the absence of Cu²⁺ addition. Under these conditions, strain 1974-GA-temA produced 34.83 ± 0.62 g/L ethanol after 8 days of fermentation, corresponding to a 20.90% ± 0.37% ethanol yield. This value markedly exceeds the outcomes of all the conducted orthogonal experiments. The fermentation optimization experiments in this study are expected to increase ethanol production during the CBP fermentation of SPR. Full article

In this study, the potential value of dried grape pomace (whole, seed, and skin) obtained from Fetească Neagră (FN) and Tămâioasă Românească (TR) as a source of secondary metabolites was evaluated following hydroethanolic extraction. The total polyphenol, flavonoid, and anthocyanin contents of FN and TR extracts have been determined, along with their antioxidant and antimicrobial activities. The investigation of seeds and the whole pomace FN extracts revealed higher levels of polyphenol, flavonoid, and anthocyanin content in comparison to those extracted from TR. Fifteen polyphenolic compounds were identified through ultra-high-performance liquid chromatography (UHPLC) analysis. The most abundant concentrations of catechin and epicatechin were detected in seed and whole pomace extracts derived from both Romanian grape varieties. The antioxidant activity was higher in the whole pomace and skin extracts derived from FN than those derived from TR. The antimicrobial evaluation demonstrated that 15 out of 18 reference pathogenic bacteria exhibited low MIC and MBC values, indicating a strong antibacterial activity of FN and TR extracts. No anti-Candida activity was observed. It can be reasonably deduced that the Fetească Neagră and Tămâioasă Românească by-products represent a sustainable resource for the development of new functional ingredients for the pharmaceutical and food industries, in alignment with the principles of the circular bioeconomy. Full article

The Jerez (Sherry) vinegars, including Vinagre de Jerez, Reserva, and Gran Reserva, are crafted from Sherry wines and are protected under the Denomination of Origin in Spain. The aim of this study was to (i) characterize the physicochemical properties and composition; (ii) investigate the impact of the aging process on color properties, phenolics, volatile compounds, and sensorial profiles; and (iii) find a marker for tracing the authenticity of non-aged (Apto) and aged Jerez vinegars. The phenolic components were identified through LC-MS/MS, whereas the volatile compounds were examined using the GC-MS/MS technique. As the aging progressed, a decrease was observed in the levels of flavonol and phenolic acids, with anthocyanin components being undetectable in non-aged and aged samples. In the Gran Reserva variety, 2-methylbutyl acetate, acetic acid, and ethanol emerged as the predominant volatile substances. The presence of oaklactone and ethyl butanoate components served as marker substances to authenticate the Gran Reserva. Additionally, alterations in color properties were noted, marked by a decrease in yellow content and an increase in the red component depending on aging. Furthermore, novel sensory descriptors, such as vanilla, clove, woody, and nutty notes, and winy character emerged in the samples with prolonged aging. Full article

The fibrinolytic kinase identified in the nereid worm (Perinereis aibuhitensis Grub) displays exceptional kinase activity, stability, and specificity, suggesting its potential as a promising candidate for the advancement of new thrombolytic drugs. In this study, a process was optimized for the production of fibrinolytic kinase using Escherichia coli, and the effects of factors such as inoculum, pH, OD, temperature, inducer concentration, and time on the protein yield were investigated. The optimum points of key parameters were determined by single-factor experiments, and the initial pH, OD, and time were determined to be significant by PB (Plackett–Burman design) with six factors at two levels of experiments. The response surface experiments highlighted the key roles of initial pH and induced OD values, and the convergence of the model and experimental data confirmed the optimal conditions and reasonable fluctuation intervals, which proved the reliability of the model. Full article

Fermented seeds and their bioactive compounds have captivated global interest due to their functional properties. Basil seeds are used worldwide in the food, cosmetic, and pharmaceutical industries, but their functional and nutritional properties after fermentation are not known. The aim of this study was to optimize the effect of fermentation on the improvement in the functional properties of basil seeds by Lactobacillus plantarum. Basil seed samples were categorized into seven water volumes (named A–G) and fermented for 24, 48, 72, and 96 h with L. Plantarum. The results show that the pH and total microbial content (TMC) significantly changed after 24 h of fermentation (p < 0.05). Fermentation significantly increased the antioxidant properties and niacin content of basil seeds compared with non-fermented control samples (p < 0.05). Fermented samples G-24, G-48, and G-72 (samples with a ratio of 1 g (basil):10 mL (water) fermented for 24,48 and 72 h), exhibited the highest DPPH and ABTS^• scavenging activity. The total polyphenol content (TPC) was most prominent in the samples G-72, G-24, and G-48, respectively. Sample G-48 showed the highest antioxidant activity. Notably, sample G-24 showed a significant increase in niacin content (64 µg/mL). These results underscore that varying moisture levels and fermentation durations have a significant impact on the nutritional/functional value of basil seeds. Overall, fermenting basil seeds with L. plantarum increased their functional properties with greater antioxidant and TPC activities as well as increased nutritional value. Full article

This study aimed to use waste figs as an alternative substrate for bacterial cellulose (BC) production by Komagataeibacter xylinus and optimize the identified process parameters to maximize the concentration of BC. Among the nutrients screened by Plackett–Burman (PB) design, yeast extract was found to be significant in BC production. Response surface methodology was used to investigate the effect of fermentation parameters on BC production. A maximum BC concentration of (8.45 g/L), which is among the highest BC concentrations reported so far, was achieved at the optimum levels of fermentation variables (initial pH 6.05, initial sugar concentration 62.75 g/L, temperature 30 °C). The utilization of response surface methodology (RSM) proved valuable in both optimizing and finding the interactions between process variables during BC production. Scanning electron microscope (SEM) analysis showed a dense structure of BC, characterized by ribbon-like nanofibrils with diameters ranging from 23 to 90 nm while the attenuated total reflection–Fourier transform infrared (ATR-FTIR) spectrum of BC confirmed that the material obtained was cellulose. The X-ray diffraction (XRD) analysis showed that the crystallinity of the BC samples was 70% for BC produced on waste fig medium and 61% for BC produced on Hestrin–Schramm (HS) medium. This is the first detailed study on the production of BC from waste figs, and the findings of this study demonstrated that waste figs can be used as an effective substrate for the production of BC. Full article

This study investigated the effects of incorporating fermented feed into the post-weaning piglet diet, with a focus on its impact on the growth, health, serum markers, immune function, diarrhea rate, and microbial community of post-weaning piglets. Forty-two post-weaning piglets (Duroc × [Landrace × Yorkshire], castrated male), with good health and similar weight (11.40 ± 1.36 kg) at 40 days of age, were randomly assigned to two groups. Throughout the trial, one group received a standard diet (control group) while the other one was given a diet supplemented with fermented feed (experimental group), respectively. The findings revealed that compared to the control group, the post-weaning piglets fed with fermented feed showed increased daily weight gain. The fermented feed also led to an increase in the height of villi in the duodenum or jejunum of post-weaning piglets (p < 0.05), accompanied by an improved ratio of villus height to crypt depth in the experimental group (p < 0.05). Furthermore, the fermented feed enhanced the richness and diversity of the intestinal microbial community in post-weaning piglets (p < 0.05), particularly increasing the relative abundance of Lactobacillaceae and Bifidobacteriaceae. These findings demonstrate that incorporating the fermented feed into the diet can reduce the diarrhea rate, improve growth performance, enhance immune function, and promote intestinal development in post-weaning piglets. Full article

This experiment was conducted to determine the nutrient composition of three agricultural by-products, namely garlic peel, sweet potato vine, and cotton straw, calculate their relative feeding value, effective energy value, and other indexes, and comprehensively evaluate their nutrient value by combining with rumen in vitro fermentation technology, with the aim of providing data references for the development and utilization of non-conventional feed resources for ruminants. The results showed that: 1) the dry matter (DM), ash, ether extract (EE), and crude protein (CP) contents of cotton straw were significantly higher than the other two feeds (p < 0.05), while the acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents of garlic peel were highly significantly higher than the others (p < 0.05); 2) the relative feed value (DMI, DDM, TDN, RFV, and RFQ) and effective energy value (GE, DE, ME, NE_m, NE_g, and NE_L) indexes of cotton straw were significantly higher than garlic peel and sweet potato vine (p < 0.01); 3) after 48 h of in vitro fermentation, the dry matter degradation rate (IVDMD) of sweet potato vine was significantly higher than the other two feeds (p < 0.01), and the cumulative gas productions (mL) and estimated gas parameters (a, b, a + b, and c) of sweet potato vine were significantly (p < 0.01) higher than those of garlic peel and cotton straw; 4) the sweet potato vine had lower pH but higher NH₃-N compared to garlic peel and cotton straw (p < 0.05). The sweet potato vine had higher propionate, iso-butyrate, butyrate, iso-valerate, and total VFA than the other two roughages, which also had the lowest acetate-to-propionate ratio. Garlic peel produced the lowest acetate, while it produced the highest valerate (p < 0.05). These findings demonstrate that all three by-products have high potential as livestock feed based on their nutritive value parameters. Comparatively, sweet potato vines exhibit higher feeding value due to their relatively moderate NDF content and superior rumen fermentation performance. Full article

In this research work, a new software tool concept and its application for the rapid and flexible development of mechanistic digital twin core models for bioprocesses in various reactor designs are presented. The newly developed software tool concept automatically combines user-selected submodels into an overall digital twin core model. The main part is a biokinetic submodel, of which three were designed for enzymatic, microbial and biocatalytic processes, which can be adapted to specific processes. Furthermore, the digital twin core model contains a physico-chemical submodel (e.g., calculating pH or oxygen transfer) and a reactor submodel. The basis of the reactor submodel is an ideally mixed stirred tank reactor. The biokinetic submodel is decoupled from the reactor submodels and enables an independent parameterisation of submodels. Connecting ideally mixed stirred tank reactor models allows for the simulation of different reactor designs. The implementation of an executable digital twin core model was accelerated, creating a new software tool concept. When the concept was applied, the development time and the computing time of digital twin core models for the cultivation of Saccharomyces cerevisiae in two coupled stirred tank reactors as well as for enzymatic hydrolysis processes in a packed-bed reactor were reduced by 90%. Full article