Search Results (33)

In this work, a food-compatible bioprocess was evaluated for the production of yeast single-cell protein from mezcal agave bagasse. Bagasse was enzymatically hydrolyzed at 10% (w/v) solids (pH 4.8, 50 °C, 24 h) using commercial enzymes. The resulting liquid was clarified by activated charcoal adsorption and filtration to obtain a hydrolysate suitable for submerged fermentation. Enzymatic hydrolysis released reducing sugars in the range of 11–17 g/L. Saccharomyces cerevisiae was cultivated on the clarified hydrolysate under submerged conditions using both flask-scale and 2 L stirred-tank bioreactor experiments. Trials were performed at flask scale with initial sugars at 8, 17, and 50 g/L, and at 2 L stirred-tank bioreactor scale with initial sugars at 20.68 g/L (R1) and 16.30 (R2) g/L. At the flask scale, final biomass concentrations increased with initial sugar level. Values reached 6.18 ± 0.27, 8.02 ± 0.55, and 9.28 ± 0.10 g/L, while crude protein remained below 10% (3.40 ± 0.15 to 8.69 ± 0.09 g/100 g dry weight). In contrast, bioreactor cultivation resulted in higher protein enrichment, with protein contents over 40% under both oxygen regimes (41.71 ± 0.47 to 45.80 ± 0.43 g/100 g dry weight). Overall, the findings support enzymatic hydrolysis coupled with controlled submerged fermentation as a scalable approach for valorizing agave bagasse into protein-enriched yeast biomass. Full article

Glycerophosphocholine (GPC) and glycerophosphoinositol (GPI) are phospholipid metabolites generated by phospholipase-mediated deacylation. In budding yeast, they enter cells via the Git1 permease; in fission yeast, the homolog is Tgp1. This study investigates why GPC is toxic to asp1-STF mutants, where Tgp1 is upregulated due to loss of Asp1 pyrophosphatase, resulting in elevated inositol pyrophosphate 1,5-IP₈. We show that S. pombe Tgp1 specifically transports GPC, explaining why GPC, but not GPI, impairs growth. Increased GPC uptake slows doubling time but does not reduce viability. Toxicity is relieved by deletion of Gde1, a phosphodiesterase that hydrolyzes GPC to choline and glycerol-3-phosphate. Mutations in either the Gde1 active site or SPX domain also suppress toxicity, and radiolabeling confirms both domains are required for enzymatic activity. GPC is toxic in cells vastly overexpressing Tgp1 even without elevated IP₈, but Gde1 loss does not suppress this effect. Similarly, in S. cerevisiae overexpressing the Candida albicans Git3 transporter, GPC provision causes toxicity independent of Gde1. Loss of Gpc1, the acyltransferase converting GPC to lysophosphatidylcholine, does not alter toxicity in either yeast. These findings highlight a conserved process by which GPC regulates growth and reveal a role for IP₈ in modulating this process. Full article

Hair growth is orchestrated by a complex cycle comprising the anagen, catagen, telogen, and exogen phases that are largely regulated by dermal papilla cells (DPCs). The disruption of oxidative balance and inflammation impairs follicle function and regeneration. Fermented yeast complex extract (FYCE) is a bioactive material derived from enzymatically hydrolyzed yeast and collagen substrates through a two-step fermentation with Lactobacillus brevis and Lactobacillus plantarum, enriched in antioxidant amino acids such as γ-aminobutyric acid (GABA) and L-alanine. In this study, we evaluated the effect of FYCE on hair regrowth, with a focus on its modulation of oxidative stress and inflammatory pathways in hydrogen peroxide (H₂O₂)-treated DPCs. FYCE treatment significantly enhanced NRF2 expression (3.2-fold compared to H₂O₂-treated DPCs), a central transcription factor controlling antioxidant defense, and concomitantly suppressed NF-κB activity (0.6-fold compared to H₂O₂-treated DPCs), a key mediator of inflammation. Importantly, FYCE also attenuated the activation of the NLRP3 inflammasome, as evidenced by the decreased expression levels of its molecular components. Complementary studies showed that FYCE increased IGF-1 (5.4-fold compared to H₂O₂-treated DPCs), Wnt10b (1.8-fold compared to H₂O₂-treated DPCs), and Wnt3a (2.9-fold compared to H₂O₂-treated DPCs), and stabilized β-catenin (2.8-fold compared to H₂O₂-treated DPCs). FYCE also showed these changes in the shaved animal skin, which was associated with increased hair follicle number (1.6-fold compared to the water-administered control group) and the anagen phase (3.0-fold compared to the water-administered control group). Collectively, our results suggest that FYCE promotes hair regrowth through the dual modulation of antioxidative and anti-inflammatory pathways, specifically by activating NRF2, inhibiting NF-κB signaling, and downregulating the NLRP3 inflammasome. These findings support FYCE as a promising candidate for further investigation as a treatment to prevent or reverse hair loss, with in vivo and clinical studies substantiating its efficacy and safety. Full article

The growing population and increasing concerns about food security and sustainability demand innovative solutions to minimize food waste and transform by-products into functional ingredients valuable to the food sector. Brewery by-products, including brewer’s spent grain (BSG) and brewer’s spent yeast (BSY), are underutilized resources despite their high protein contents and potential as sustainable food ingredients. This study aimed to transform BSG and BSY into protein hydrolysates (BSGH and BSYH, respectively) through enzymatic hydrolysis and thus add value to these brewery industry by-products to be used in the food industry. These protein hydrolysates were incorporated into non-alcoholic malt beverages at three different concentrations, and their effects on the physicochemical properties, including color, kinematic viscosity, turbidity, foaming capacity and foam stability, of the non-alcoholic malt beverages were evaluated. Both BSGH and BSYH exhibited higher water solubility (WS) and lower water binding capacity (WBC) values when compared to their native non-hydrolyzed forms, enhancing their suitability as ideal ingredients for protein supplementation of a wide range of food and beverage products. The production of peptides of varying sizes underscored the effectiveness of enzymatic hydrolysis which resulted in an increase in cysteine and methionine levels in BSYH but a decrease in BSGH. The addition of BSGH and BSYH increased the kinematic viscosity and turbidity but reduced the lightness values in color of the non-alcoholic malt beverages. When the properties of the protein hydrolysates were compared, BSYH was more effective than BSGH in forming foams and maintaining their stability for longer periods. These findings highlight the potential of brewery by-products, after enzymatic hydrolysis, as protein-rich ingredients that can support more sustainable food systems and contribute to the nutritional enhancement of various low-protein food and beverage products. Full article

Brewer’s spent grain (BSG), the most abundant by-product from breweries, is mainly discarded or used as animal feed. However, to increase the brewing sustainability, biotechnological utilization of BSG is a much preferred solution. This study examined the fermentation of BSG, composed of old wheat bread and barley malt, by metabolic activity of Saccharomyces cerevisiae on both hydrolyzed and non-hydrolyzed media. Enzymatic hydrolysis with Viscozyme^® W FG for 6 h was selected as the most effective and was used in the further research step to prepare the hydrolyzed BSG-based medium. Both media supported almost uniform yeast growth (numbers of S. cerevisiae cells was about 8 log₁₀ CFU/g) in an acidic environment (pH value was about 5), but fermentation of hydrolyzed BSG resulted in 20% higher sugar consumption and 10% higher total titratable acidity. These findings underscore the potential of enzymatic pretreatment to improve fermentation performance. The adaptability of S. cerevisiae and the fermentability of both substrates suggest promising potential for scalable BSG valorization strategies in circular food systems. Full article

The enzymes in honey can originate not only from bees and the plants from which the bees collect pollen and nectar but also from feed provided by beekeepers. Enzymes that hydrolyze sucrose—present in honey (α-glucosidase) or honey adulterated with invert syrup (β-fructofuranosidase)—can be distinguished using zymography, where enzymatic bands are detected with nitroblue tetrazolium (NBT) after sugar removal via ultrafiltration. This method enables the identification of honey produced in hives that have been improperly fed with invert syrup, leading to the mixture of natural honey and syrup, and offers a practical tool to detect indirect adulteration. The NBT assay, in combination with ultrafiltration, was used to determine the isoelectric point of honey bee α-glucosidases. The pI value of 6.63 for isoforms found in the head, midgut, and natural honey extracts during winter can be attributed to α-glucosidase III. Two additional isoforms with isoelectric points of 5.20 and 5.77 were observed in the midgut extract and may correspond to α-glucosidase I and II. The difference between α-glucosidase and β-fructofuranosidase was confirmed using a substrate specificity test, followed by thin-layer chromatography, where it was confirmed that α-glucosidase from natural honey, bee head, and bee midgut does not hydrolyze raffinose, in contrast to yeast β-fructofuranosidase. Full article

This study developed a solid-state fermentation system based on Trichoderma harzianum, which significantly enhanced the nutritional value of distiller’s grain (DG) feed through a multi-stage synergistic treatment process. During the cellulase production phase, rice husk was used as an auxiliary material, and specific degradation of DGs was effectively enhanced. Through optimization using response surface methodology, the optimal enzyme production conditions were determined. The filter paper enzyme activity reached a peak of 1.45 U/gds (enzyme activity per gram of dry substrate) when the moisture content was 53%, the fermentation time was 3 days, and the Tween-80 dosage was 0.015 mL/g (dry weight basis). Under these conditions, the crude enzyme solution was used to hydrolyze DGs. Compared to original DGs, the content of reducing sugars increased by 10.75%. In the stage of protein production, segmented hydrolysis fermentation (SHF) and simultaneous saccharification fermentation (SSF) processes were employed using yeast. The results showed that SSF pathway showed better performance, and the true protein content reached 15.16% after 11 days, an increase of 41.5% compared to the control. Finally, through secondary fermentation regulated by Lactobacillus fermentum, the flavor of the feed was significantly improved. This study innovatively integrated bio-enzymatic hydrolysis and multi-strain synergistic fermentation technologies, providing a novel strategy for the efficient and sustainable production of protein feed based on DGs. Full article

Massive blooms of Ulva species, commonly known as green tides, pose serious ecological threats by disrupting coastal ecosystems and requiring costly removal efforts. This study presents a nature-based solution by seasonally valorizing Ulva ohnoi, a bloom-forming macroalga dominant in Jeju Island, South Korea. Biomass was collected across all four seasons and subjected to phylogenetic identification, biochemical characterization, and bioresource processing. Despite environmental fluctuations, tufA-based analysis confirmed U. ohnoi as the sole species present year-round. Carbohydrate content peaked in spring (55.35%) and was lowest in summer (45.74%), corresponding to maximum reducing sugar of 36.49 g/L in winter and 36.24 g/L in spring following acid-enzymatic hydrolysis. The maximum ethanol fermentation using Saccharomyces cerevisiae produced up to 17.12 g/L ethanol in spring with a yield of 0.47 g/g. Post-fermentation residues were enzymatically hydrolyzed into Ulva Ethanol Residue Medium (UERM), which supported yeast growth and fermentation comparable to commercial YPD medium, achieving final optical densities of 8.3–8.5 and ethanol production of 16.5–16.8 g/L. Alanine, valine, and proline were the most abundant amino acids in UERM, supporting its suitability as a nitrogen source. These findings highlight the potential of integrating green tide mitigation with renewable energy and nutrient recycling through seasonal, localized biorefineries aligned with circular marine bioeconomy principles. Full article

Fermented vegetables are highly valued by consumers for their distinct flavors and rich nutritional content. Microbial fermentation imparts distinct flavors to these vegetables, with red yeast being a common microorganism involved in the fermentation process. However, studies on the impact of red yeast on flavor development in fermented vegetables remain scarce. This study employed multi-omics to analyze the effect of glycosidase produced by Rhodotorula mucilaginosa on the release of bound flavor compounds in vegetables. The results indicate that the yeast possesses multiple glycosidase-encoding genes, with the activities of α-galactosidase, β-glucosidase, and α-mannosidase being detected. Following the inoculation of yeast into fermented vegetable juice, a significant increase was observed in the expression of the β-glucosidase gene (bglX) and the α-glucosidase maltase gene (malL), alongside an increase in the content of flavor compounds correlated with the enzymatic activity detected. The application of commercial glycosidase to vegetable juice resulted in increased levels of cis-2-pentenol, hyacinthin, geranylacetone, and 1-dodecanol, consistent with findings from yeast-fermented vegetable juice. Thus, Rhodotorula mucilaginosa can secrete glycosidases that hydrolyze and release endogenous bound flavor compounds in vegetables, thereby enhancing the flavor quality of the final product. Full article

We have previously shown that 2-thiouridine (S2U), either as a single nucleoside or as an element of RNA chain, is effectively desulfurized under applied in vitro oxidative conditions. The chemically induced desulfuration of S2U resulted in two products: 4-pyrimidinone nucleoside (H2U) and uridine (U). Recently, we investigated whether the desulfuration of S2U is a natural process that also occurs in the cells exposed to oxidative stress or whether it only occurs in the test tube during chemical reactions with oxidants at high concentrations. Using different types of eukaryotic cells, such as baker’s yeast, human cancer cells, or modified HEK293 cells with an impaired antioxidant system, we confirmed that 5-substituted 2-thiouridines are oxidatively desulfurized in the wobble position of the anticodon of some tRNAs. The quantitative LC-MS/MS-MRMhr analysis of the nucleoside mixtures obtained from the hydrolyzed tRNA revealed the presence of the desulfuration products of mcm5S2U: mcm5H2U and mcm5U modifications. We also observed some amounts of immature cm5S2U, cm5H2U and cm5U products, which may have indicated a disruption of the enzymatic modification pathway at the C5 position of 2-thiouridine. The observed process, which was triggered by oxidative stress in the living cells, could impair the function of 2-thiouridine-containing tRNAs and alter the translation of genetic information. Full article

The present work focuses on the utilization of potato peel waste for the production of bioethanol. In the present study, extensive screening was undertaken to isolate amylolytic and cellulolytic microbes using starchy biomass. After confirming the chemical composition of potato peel waste (PPW), several trials were performed to enhance the amylase and cellulase production from Bacillus subtilis to hydrolyze the PPW in submerged fermentation. Optimization of physical parameters was performed using both commercial and indigenous media from enzymatically hydrolyzed PPW. Different routes of various combinations were designed to enhance bioethanol production. The maximum ethanol titer of 0.50% and 0.41% was recorded in Route B and A, i.e., separate saccharification and ethanol fermentation and consolidated fermentation. Simultaneous saccharification and fermentation (SSF) also measured a good ethanol yield of 0.46%. The fermented residual cake was checked for nutritional components and showed a high content of protein and amino acids because of the addition of unicellular yeasts. This cake can be utilized as an animal feed supplement. Full article

The study involves the use of commercial cellulase Cellic CTec2 in combination with two in-house xylanases, PxXyn10A (XynA), a recombinant purified enzyme from Paenibacillus xylanivorans A59, and a xylanase enzymatic extract from native Moesziomyces aphidis PYCC 5535T (MaPYCC 5535T), for the enzymatic hydrolysis of pretreated blue agave bagasse (BAB) at the high solids load of 20% (w/v). Three different combinations of cellulase and xylanases were evaluated. When Cellic^® CTec2 was used at a dosage of 10 FPU/g oven-dried solids (ODS) supplemented with XynA or MaPYCC 5535T at an endo-xylanase dosage of 100 U/g ODS, increases in the xylose yield of 30% and 33%, respectively, were obtained. When applying in-house xylanases alone (at an endo-xylanase dosage of 100 U/g ODS), xylan in BAB was selectively hydrolyzed into xylose with 5% yield with MaPYCC 5535T, while no xylose was detected with XynA. Interestingly, a synergic effect of Cellic^® CTec 2 with both xylanases was observed when using a low dosage of 1 FPU/g ODS (allowing for some liquefaction of the reaction mixture), promoting xylose and glucose release by either xylanase. A higher concentration of monomeric sugars was obtained with 10 FPU/g ODS of Cellic^® Ctec 2 supplemented with 100 U/g ODS of MaPYCC 5535T, followed by XynA. The improvement in saccharification through the synergistic combination of in-house xylanases and commercial cellulases allows for the obtention of sugar-rich hydrolysates, which enhances the technical sustainability of the process. Hydrolysates were then fermented using recombinant Cellux 4^TM yeast to yield 45 g/L ethanol, representing an increase of about 30% with respect to the control obtained with only the commercial cellulase cocktail. The surface modification of agave biomass with the different combinations of enzymes was evidenced by scanning electron microscopy (SEM). Full article

Over the years, the world has continued to be plagued by type 2 diabetes (T2D). As a lifestyle disease, obese individuals are at higher risk of developing the disease. Medicinal plants have increasingly been utilized as remedial agents for managing metabolic syndrome. The aim of the present study was to investigate the in vitro anti-hyperglycemic and anti-lipidemic potential of Croton gratissimus herbal tea infusion. The inhibitory activities of C. gratissimus on carbohydrate (α-glucosidase and α-amylase) and lipid (pancreatic lipase) hydrolyzing enzymes were determined, and the mode of inhibition of the carbohydrate digestive enzymes was analyzed and calculated via Lineweaver–Burk plots and Michaelis Menten’s equation. Its effect on Advanced Glycation End Product (AGE) formation, glucose adsorption, and yeast glucose utilization were also determined. High-performance liquid chromatography (HPLC) was used to quantify the possible phenolic compounds present in the herbal tea infusion, and the compounds were docked with the digestive enzymes. C. gratissimus significantly (p < 0.05) inhibited α-glucosidase (IC₅₀ = 60.56 ± 2.78 μg/mL), α-amylase (IC₅₀ = 35.67 ± 0.07 μg/mL), as well as pancreatic lipase (IC₅₀ = 50.27 ± 1.51 μg/mL) in a dose-dependent (15–240 µg/mL) trend. The infusion also inhibited the non-enzymatic glycation process, adsorbed glucose effectively, and enhanced glucose uptake in yeast cell solutions at increasing concentrations. Molecular docking analysis showed strong binding affinity between HPLC-quantified compounds (quercetin, caffeic acid, gallic acid, and catechin) of C. gratissimus herbal tea and the studied digestive enzymes. Moreover, the herbal tea product did not present cytotoxicity on 3T3-L1 cell lines. Results from this study suggest that C. gratissimus herbal tea could improve glucose homeostasis and support its local usage as a potential anti-hyperglycemic and anti-obesogenic agent. Further in vivo and molecular studies are required to bolster the results from this study. Full article

Biomass from various types of organic waste was tested for possible use in hydrogen production. The composition consisted of lignified samples, green waste, and kitchen scraps such as fruit and vegetable peels and leftover food. For this purpose, the enzymatic pretreatment of organic waste with a combination of five different hydrolytic enzymes (cellulase, amylase, glucoamylase, pectinase and xylase) was investigated to determine its ability to produce hydrogen (H₂) with the hydrolyzate produced here. In course, the anaerobic rod-shaped bacterium T. neapolitana was used for H₂ production. First, the enzymes were investigated using different substrates in preliminary experiments. Subsequently, hydrolyses were carried out using different types of organic waste. In the hydrolysis carried out here for 48 h, an increase in glucose concentration of 481% was measured for waste loads containing starch, corresponding to a glucose concentration at the end of hydrolysis of 7.5 g·L⁻¹. In the subsequent set fermentation in serum bottles, a H₂ yield of 1.26 mmol H₂ was obtained in the overhead space when Terrific Broth Medium with glucose and yeast extract (TBGY medium) was used. When hydrolyzed organic waste was used, even a H₂ yield of 1.37 mmol could be achieved in the overhead space. In addition, a dedicated reactor system for the anaerobic fermentation of T. neapolitana to produce H₂ was developed. The bioreactor developed here can ferment anaerobically with a very low loss of produced gas. Here, after 24 h, a hydrogen concentration of 83% could be measured in the overhead space. Full article

Sugar beet molasses is a low-value byproduct from the sugar industry. It contains significant amounts of sucrose (approx. 50% (w/w)), which can be used for many different applications, for example, as feedstock for the production of fuel (as ethanol) and biobased chemicals such as 5-hydoxymethyl furfural (HMF). To produce platform chemicals, sucrose is hydrolyzed into its monomeric C6 sugars: glucose and fructose. When comparing the hydrolysis rates of molasses with a pure sucrose solution, the specific reaction rate is much slower (Q_p/x,60min = 93 and 70 g_prod L⁻¹ h⁻¹ g_cell⁻¹ for pure sucrose and crude molasses, respectively) at the same sucrose concentration (300 g/L) and process conditions. To clarify why molasses inhibits the enzymatic hydrolysis rate, the influence of its viscosity and inorganic and organic composition was investigated. Also, the effects of molasses and treated molasses on pure enzymes, invertase (from Saccharomyces cerevisiae, 0.05 mg/mL), compared with hydrolysis using whole cells of Baker’s yeast (3 mg/mL), were tested. The results indicate an inhibitory effect of potassium (Q_p/x,60min = 76 g_prod L⁻¹ h⁻¹ g_cell⁻¹), generally at high salt concentrations (Q_p/x,60min = 67 g_prod L⁻¹ h⁻¹ g_cell⁻¹), which could be correlated to the solution’s high salt concentrations and possibly the synergistic effects of different ions when applying concentrations that were four times that in the molasses. Also, the viscosity and sucrose purity seem to have an effect, where pure sucrose solutions and thick juice from the sugar mill yielded higher hydrolysis rates (Q_p/x,60min = 97 g_prod L⁻¹ h⁻¹ g_cell⁻¹) than molasses-type solutions with a higher viscosity (Q_p/x,60min = 70–74 g_prod L⁻¹ h⁻¹ g_cell⁻¹). Attempting to further understand the effects of different components on the invertase activity, an in silico investigation was performed, indicating that high salt concentrations affected the binding of sucrose to the active site of the enzyme, which can result in a lower reaction rate. This knowledge is important for future scale-up of the hydrolysis process, since reduced hydrolysis rates require larger volumes to provide a certain productivity, requiring larger process equipment and thereby higher investment costs. Full article