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At least 19 recordsLinked to original sources
PubMed1976

Antimycin A fermentation. II. Fermentation in aerated-agitated fermenters.

Fermentation characteristics, previously studied in shake flasks, were reproduced in aerated-agitated fermenters, using three strains of Streptomyces sp. which had been selected for their high antimycin A productivity in shake flasks. Fermentation in fermenters was run in three stages. The medium consisted of soy flour, glucose, ammonium sulfate and calcium carbonate; initial pH was 7.2 approximately 7.5, and temperature 25 degrees C. The course of fermentation was then modified to encourage maximal growth and eliminate the intermediate lag period observed in shake flasks. Useful corrections included continuous addition of soybean oil at 1.25 %/day and maintenance of pH at 6 by addition of ammonium hydroxide on demand. The ammonium hydroxide added also served as a rapidly utilized nitrogen source and could not be replace by NaOH or KOH. Under optimal conditions antimycin A was produced at constant rate from the second to the sixth day, when maximum yields of more than 9 g/liter were attained. A procedure for antimycin A extraction is described.

Antimycin A↗
PubMed2026

Integrated electronic nose, GC-MS, and metagenomic analyses reveal volatile flavor and microbial community differences in heap-fermented grains of Jiangxiangxing Baijiu across different fermentation degrees.

The fermentation degree of heap-fermented grains in Jiangxiangxing Baijiu production is a critical factor influencing base Baijiu quality. However, conventional assessment methods largely rely on empirical experience and therefore suffer from limited objectivity and accuracy. In this study, integrated volatile profiling and metagenomic approaches were employed to investigate volatile characteristics and microbial functional potential differentiation in fermented grains with different fermentation degrees (under-fermented, normally fermented, and over-fermented). Significant differences in physicochemical properties were observed among fermentation degrees, particularly in acidity and reducing sugar content. Electronic nose analysis revealed distinct sensor response patterns among different fermentation degrees, indicating differences in overall volatile odor fingerprint patterns. A total of 81 volatile compounds were identified by HS-SPME-GC-MS, with aldehydes, ketones, and pyrazines showing pronounced variations among fermentation degrees, and acetaldehyde exhibiting strong discriminatory potential. LEfSe analysis identified 18 microbial taxa as potential biomarkers associated with different fermentation degrees, including Pichia kudriavzevii, Lentibacillus daiqui, and Acetobacter pasteurianus. Correlation analysis revealed significant positive associations between acetaldehyde levels and Acetobacter abundance. Furthermore, KEGG, CAZy, and eggNOG analyses revealed differentiated functional potentials among fermentation degrees, providing insights into the potential metabolic basis associated with flavor differentiation. Overall, these findings highlight that fermentation degree differentiation is closely associated with coordinated changes in physicochemical conditions, microbial communities, and functional potentials, providing ecological insights into flavor differentiation and theoretical support for objective fermentation degree evaluation and quality control of Jiangxiangxing Baijiu production.

Fermentation↗
PubMed1977

Enamel microhardness and fluoride uptake underneath fermenting and non-fermenting artificial plaque.

Washed cells of Streptococcus sanguis were used to form artificial plaque on the surface of bovine enamel and incubated underneath buffer solutions, initial pH 6, for 36 h at 37 degrees C. The decrease in the microhardness of the enamel surface under fermenting "plaque" could be prevented with fluoride. Enamel under a fermenting "plaque" took up significantly more (P less than 0.0u) fluoride than enamel under a non-fermenting "plaque" (initial F- in buffer: 10 parts/10(6)). The artificial plaque did not accumulate fluoride. Within fermenting "plaques/, the pH decreased significantly more without flouride (P less than 0.01) than with fluoride. Fluoride combined with sucrose more than negated the softening of the enamel caused by sucrose fermentation, i.e. it increased the hardness above the original values. The diffusion of fluoride through the fermenting artificial plaque was more rapid than through a non-fermenting plaque. These findings suggest that caries-conducive circumstances may promote fluoride uptake by enamel compared with non-caries-conducive circumstances.

Animals↗
PubMed1976

[Fermentation of pyruvate by 7 species of phototrophic purple bacteria].

The dark, anaerobic fermentation of pyruvate under growth conditions was examined with the following species of phototrophic purple bacteria: Rhodospirillum rubrum strains Ha and S1, Rhodopseudomonas gelatinosa strain 2150, Rhodopseudomonas acidophila strain 7050, Rhodopseudomonas palustris strain ATCC 17001, Rhodopseudomonas capsulata strains Kb1 and 6950, Rhodopseudomonas sphaeroides strain ATCC 17023, and Chromatium vinosum strain D. Fermentation balances were established for all experiments. Under fermentative conditions cell protein and dry weight increased only slightly, if at all. The species differed considerably in their fermentative activity; R. rubrum and R. gelatinosa exhibited the highest rates (2-8 mumoles pyruvate/mg protein-h). R. acidophila and R. capsulata showed an intermediate fermentation rate (0.4--2.0 mumoles pyruvate/mg protein-h), while the other strains tested fermented at quite low rates (0.2-0.4 mumoles pyruvate/mg protein-h). The extremes of fermentation times were from 30-380 hours. Based on the products of fermentation which were formed in addition to acetate, formate, and CO2, the species can be grouped as follows: a) R. rubrum, R. gelatinosa, and R. sphaeroides additionally form propionate. b) R. gelatinosa, R. palustris, R. capsulata, R. sphaeroides, and C. vinosum additionally form lactate. R. palustris also produces butyrate. c) R. acidophila and R. capsulata additionally form much 2,3-butanediol, acetoin, and diacetyl. Small amounts of acetoin were formed by the rest of the strains. A comparison of the fermentation of pyruvate by normal and starved cells (4 days in the light without a carbon source) of R. rubrum and R. gelatinosa shows that the latter ferment more slowly and produce less acetate and formate, but more propionate or lactate. The fermentation of pyruvate by R. rubrum was also studied in cultures in which the pH fell (7.2--6.6). Compared with the fermentation at neutral pH (7.3, 7.4), the following differences were found: a slower fermentation rate, an increased production of dry weight, an increased formation of propionate, but a reduced formation of acetate and a very low production of formate.

Acetates↗
PubMed2025

High-fat and low-fat fermented milk and cheese intake, proteomic signatures, and risk of all-cause and cause-specific mortality.

PURPOSE: This study aimed to examine the associations between the intake of high- and low-fat fermented dairy (cheese and fermented milk), their proteomic profiles, and mortality risk. METHODS: This cohort study included 25,187 participants (mean age 57.7 years, 60.9% females). Fermented dairy intake was assessed by a modified diet history method. In a random subset of this cohort (n&#x2009;=&#x2009;4359), we constructed proteomic signatures for fermented dairy intake using 136 candidate plasma proteins. RESULTS: During 23.5 years of follow-up, 9742 participants died. High-fat cheese (>&#x2009;20% fat) intake was inversely associated with risk of all-cause mortality (HR for an increment of 20&#xa0;g/day, 0.97; 95% CI, 0.96-0.99, P&#x2009;<&#x2009;0.001) and cardiovascular disease mortality (HR, 0.96; 95% CI, 0.93-0.99, P&#x2009;=&#x2009;0.006). Low-fat cheese intake showed an inverse association with all-cause mortality (HR, 0.98; 95% CI, 0.96-1.00, P&#x2009;=&#x2009;0.047). Low-fat fermented milk intake was inversely associated with all-cause mortality (HR for an increment of 250&#xa0;g/day, 0.91; 95% CI, 0.85-0.97, P&#x2009;=&#x2009;0.006), while high-fat fermented milk (>&#x2009;2.5% fat) showed null association. A total of 42, 26, 0, and 39 proteins were identified for the signature of high-fat cheese, low-fat cheese, high-fat fermented milk, and low-fat fermented milk, respectively. Inverse associations with all-cause mortality were observed for all three signatures with identified proteins. The identified proteins were involved in biological pathways related to immune response and inflammation. CONCLUSION: Our study indicated that consuming high-fat cheese, low-fat cheese, and low-fat fermented milk was linked to survival benefits. Plasma proteins improve our understanding of the health effects of fermented dairy.

Humans↗
PubMed2026

Simmondsia chinensis (jojoba) cake fermentation: A new, sustainable technology for advanced skin and scalp care ingredients.

OBJECTIVE: Simmondsia chinensis is a well-known commercially popular plant from which jojoba oil is extracted. Jojoba cake is a sustainably produced, intractable by-product of the jojoba seed oil extraction currently used principally as a fertilizer or burned as fuel. Fermentation work conducted with various microorganisms, including Lactobacillus plantarum, Saccharomyces cerevisiae and Streptococcus thermophilus, sustainably grown on aqueous jojoba cake fermented the cake, liberating jojoba-based amino acids, peptides and proteins. The ferments have been examined chemically and via in&#xa0;vitro cell and tissue studies to develop new skin and scalp care targeted ingredients. METHODS: The jojoba cake contained nutrients (proteins, sugars and lipids) that self-sustain aqueous bacterial fermentation. The ferments were examined on 3D tissue models in&#xa0;vitro via human genomic microarrays. A ferment produced by Lactobacillus plantarum was further tested in&#xa0;vitro using ELISA protein assays on skin cell cultures. A 56-day clinical study on 46 individuals examined the influence of 1.0% of the Lactobacillus ferment on collagen expression using Diffuse Reflectance Spectroscopy (DRS). RESULTS: Gene responses were measured on 244+ genes known to have skin functions. It was found that the Lactobacillus ferment showed the greatest upregulation of skin-associated genes, and three highly upregulated proteins were examined more closely in&#xa0;vitro using ELISA protein assays: collagen-1A1, protocadherin-18 and opioid growth factor receptor. Each protein was upregulated in a dose-dependent fashion. The collagen analysis by DRS demonstrated a statistically significant increase in collagen fluorescence on Day 28 and Day 56 compared to baseline and placebo cream. Further mapping of the collagen fluorescence was done on the individuals using the active formulation at Days 0, 28 and 56. CONCLUSION: Jojoba cake presents a new source of sustainably grown biomass, but the cake is not suitable for topical applications. Fermentation produces components more suitable for topical care. In&#xa0;vitro studies demonstrated upregulation of three skin proteins associated with healing skin. Further studies also employed a newly emerging spectroscopic technique to measure collagen fluorescence in the skin in&#xa0;vivo, the results supporting in&#xa0;vitro work indicating the ferment made with Lactobacillus was able to stimulate collagen synthesis in the skin.

Lactobacillus↗
PubMed1975

Studies on the energy metabolism during anaerobic fermentation of glucose by baker's yeast.

As a result of the intimate association of ADP phosphorylation with alcoholic fermentation, resulting in the synthesis of 2 mole ATP per mole glucose fermented, it may be calculated that a minimum of 672 mucal heat development may be expected for every mm-3 CO2 developed during alcoholic fermentation. When all ATP produced would be fully de-phosphorylated to ADP + Pi (e.g. by ATP-ase activity) a maximum heat development of 1200 mucal per mm-3 CO2 could be expected. Using the LKB-Flow-Microcalorimeter for measurement of heat development and at the same time the Warburg technique for measuring CO2 development during anaerobic glucose fermentation of a baker's yeast suspension, the heat development per mm-3 CO2 produced was calculated over a fermentation period of 90 min. Maintenance of strict anaerobic conditions in the Flow-Microcalorimeter vessel was complicated by diffusion of traces of oxygen via the Teflon transport lines, resulting in excessive heat development values, not representative for the alcoholic fermentation. This problem could be circumvented by removal of traces of oxygen by means of addition of the enzyme glucose-oxidase. Poisoning the respiratory enzyme system of the yeast by addition of KCN or azide, or using respiratory-deficient mutants of the yeast also resulted in heat development values, inherent with alcoholic fermentation. The values obtained were very close to the minimum of 672 mucal per mm-3 CO2, at least during the initial phases of fermentation, indicating that ADP regeneration from ATP, essential for maintaining the high fermentation rate, is not primarily the result of ATP-ase activity, but must be due to participation of ATP in energy-requiring synthetic reactions.

Adenosine Diphosphate↗
PubMed1979

Change from homo- to heterolactic fermentation by Streptococcus lactis resulting from glucose limitation in anaerobic chemostat cultures.

Lactic streptococci, classically regarded as homolactic fermenters of glucose and lactose, became heterolactic when grown with limiting carbohydrate concentrations in a chemostat. At high dilution rates (D) with excess glucose present, about 95% of the fermented sugar was converted to l-lactate. However, as D was lowered and glucose became limiting, five of the six strains tested changed to a heterolactic fermentation such that at D = 0.1 h(-1) as little as 1% of the glucose was converted to l-lactate. The products formed after this phenotypic change in fermentation pattern were formate, acetate, and ethanol. The level of lactate dehydrogenase, which is dependent upon ketohexose diphosphate for activity, decreased as fermentation became heterolactic with Streptococcus lactis ML(3). Transfer of heterolactic cells from the chemostat to buffer containing glucose resulted in the nongrowing cells converting nearly 80% of the glucose to l-lactate, indicating that fine control of enzyme activity is an important factor in the fermentation change. These nongrowing cells metabolizing glucose had elevated (ca. twofold) intracellular fructose 1,6-diphosphate concentrations ([FDP](in)) compared with those in the glucose-limited heterolactic cells in the chemostat. [FDP](in) was monitored during the change in fermentation pattern observed in the chemostat when glucose became limiting. Cells converting 95 and 1% of the glucose to l-lactate contained 25 and 10 mM [FDP](in), respectively. It is suggested that factors involved in the change to heterolactic fermentation include both [FDP](in) and the level of lactate dehydrogenase.

Acetates↗
PubMed2026

Assessing the diversity and functional profile of the "microbial proteome" in fermented foods.

Fermented foods are staples in diets worldwide and are known for their health benefits. Microorganisms are the key to fermented food production as they convert raw substrates into digestible, nutritious, and health-promoting products. While microbes are essential for fermented food production, their contribution to the dietary protein profile of the final food product in terms of microbial biomass is largely unknown. We analyzed proteins from 17 fermented foods using metaproteomics to identify and quantify microbial and food-derived proteins. We found that microbial proteins contribute up to 11% of the total protein content in fermented foods and comprise as much as 60% of the total number of identified proteins. These microbial proteins included many for central functions in microbial cells, such as glycolysis enzymes, translation machinery, and chaperones, as well as proteins for specialized functions that are important for the ecological niches in food fermentation, such as carbohydrate degrading enzymes and proteases. Some of these microbial proteins, such as proteases, could impact gut physiology. These findings highlight the substantial contribution of microbial proteins to the nutritional and functional profile of fermented foods, which may have important implications for interactions with the gut microbiota and health outcomes.

Fermented Foods↗
PubMed2026

Yeast Strain Development and Process Intensification in High-Gravity Fermentation.

High- and very-high-gravity (HG/VHG) fermentation increases substrate loading and product titers, thereby improving fermenter utilisation and potentially reducing water use and downstream processing requirements. Initially developed for brewing and fuel ethanol production, these approaches are now applied more broadly in food, beverage, and bioproduct manufacturing. This MiniReview summarises operational definitions and industrial drivers of HG/VHG fermentation and examines the associated constraints in rheology, mass and heat transfer, osmotic and ethanol stress, nutrient availability, and oxidative damage. Yeast improvement strategies are reviewed, including adaptive laboratory evolution, mutagenesis, genome shuffling, multiplex genome editing, non-conventional yeasts, and multi-omics-guided selection. Process developments such as no-cook simultaneous liquefaction, saccharification and fermentation (SLSF), enzyme formulation, nutrient management, and in situ product recovery are considered together with applications in alcoholic beverages, organic acids, microbial lipids, and other value-added products. The review also discusses coproduct valorisation and the need to integrate strain development with process design. Current evidence supports HG/VHG fermentation as a useful process-intensification platform, although performance and sustainability depend strongly on feedstock, operating conditions, product requirements, and the basis used to report fermentation outcomes.

circular bioeconomy↗
PubMed2026

Bioactive macromolecules in LAB-fermented cereals: Mechanisms of formation, functional properties, and health benefits.

Cereal and pseudo-cereal based fermented food products represent a substantial segment of global diet, nutrition as well as food security. Fermentation, especially by Lactic Acid Bacteria (LAB) increases the nutritional and functional values of foods by increasing palatability, bioavailability and minimizing antinutritional factors. LAB plays a pivotal role in synthesizing bioactive peptides, vitamins, minerals and reducing anti-nutrients parallelly. This review elucidates the mechanism through which LAB revamping nutritional macromolecules, such as peptides and polysaccharides, during fermentation and their role in the development of traditional as well as modern fermented foods. Additionally, these fermented foods have been associated with several health benefits. Recent advancement in biotechnology such as genome sequencing, functional genomics, and AI-assisted bioinformatics, have significantly enhanced our understanding of the diversity of LAB, the metabolism, and adaptation mechanisms. The combination of in silico and experimental methods has enabled the development of novel food enzymes as well as highly precise fermentation processes. Together with new innovations, growing demands for quality, consistency, safety as well as health benefits point out the significance of continued research. More studies employing both conventional and modern methods are necessary to explore these food groups completely and achieve better food quality, increased nutrition, more health benefits and comprehensive socioeconomic advantages.

Bioactive macromolecules↗
PubMed1976

Bacterial fermentation of cheese whey for production of a ruminant feed supplement rich in curde protein.

A simple and efficient process for the production of a ruminant feed supplement, rich in crude protein (defined as total N X 6.25), by bacterial fermentation of cheese whey has been developed. The lactose in unpasteurized whey is fermented to lactate acid by Lactobacillus bulgaricus at a temperature of 43 degrees C and pH 5.5. The lactic acid produced is continually neutralized with ammonia to form ammonium lactate. The fermented product is concentrated by evaporation to a solids content of about 70% and adjusted to pH 6.8 with additional ammonia. The concentrated product contains about 55% crude protein. Approximately 6 to 8% of the crude protein is derived from bacterial cells. 17% from whey proteins, and 75 to 77% from ammonium lactate. The efficiency of conversion of lactose to lactic acid usually exceeds 95%. The fermentation time is greatly reduced upon the addition of 0.2% yeast extract or 0.1% corn steep liquor as a source of growth factors. Whey containing lactose at concentrations up to 7% can be fermented efficiently, but at higher concentrations lactose is fermented incompletely. The process has been scaled up to a pilot plant level, and 40 tons of concentrated product were produced fro animal feeding trials, without ever encountering putrefactive spoilage.

Animal Feed↗
PubMed2025

Consumption of traditional Sardinian fermented milk promotes changes in the rat gut microbiota composition and functions.

BACKGROUND: Fermented milk products are part of the staple diet for many Mediterranean populations. Most of these traditional foods are enriched with lactobacilli and other lactic acid bacteria, as well as with metabolites resulting from lactose fermentation. Currently, there is very little scientific knowledge on how dietary supplementation with fermented milk affects the composition of the gut microbiota and its metabolic activities. RESULTS: We integrated 16&#xa0;S rRNA gene-based taxonomic profiling with metaproteomics-based functional analysis to investigate gut microbiota changes in rats exposed to an 8-week dietary supplementation with casu axedu, a traditional fermented milk produced within rural communities in Sardinia (Italy). Several microbial taxa showed a significantly increased abundance at the end of the dietary treatment, including Phascolarctobacterium, Prevotella, Blautia glucerasea, and Lactococcus lactis, while Bacteroides dorei and Helicobacter rodentium were decreased compared to the control rats. Metaproteomic analysis highlighted a striking reshaping of the Prevotella proteome in agreement with its blooming in casu axedu-fed animals, suggesting an increase of the glycolytic activity through the Embden-Meyerhof-Parnas pathway over the Entner-Doudoroff pathway. Moreover, an increased production of enzymes involved in succinate biosynthesis was observed, which in turn significantly boosted the abundance of Phascolarctobacterium and its production of propionate. Fermented milk consumption also promoted microbial synthesis of branched chain essential amino acids L-valine and L-leucine. Finally, metaproteomic data indicated a reduction of bacterial virulence factors and host inflammatory markers, suggesting that the consumption of casu axedu can have beneficial effects on the gut mucosa health. CONCLUSIONS: Our integrated multi-omics approach reveals that dietary supplementation with the traditional Sardinian fermented milk, casu axedu, induces significant shifts in the rat gut microbiota composition and function, characterized by the enrichment of beneficial taxa and metabolic pathways associated with improved gut health and reduced inflammation.

Animals↗
PubMed1978

Absorption of colostral proteins by newborn calves fed unfermented, fermented, or buffered colostrum.

Unfermented, frozen colostrum from the first three postpartum milkings of 10 cows was thawed, pooled, and treated to produce three diets: 1) unfermented, 2) fermented (7 days at 25 to 27 C), and 3) fermented (as in 2) with pH adjusted to match that of unfermented colostrum. Eighteen newborn, unsuckled Holstein calves were assigned randomly to one of the three diets. Colostrum diets were thawed and fed at 0, 8, 16, 24, and 36 h. Blood was sampled at 0, 4, 8, 16, 24, and 48 h. Minimal breakdown of colostral gamma-globulin and immunoglobulin G (IgG) occurred during fermentation. Protein breakdown during fermentation was associated primarily with the casein fraction. Concentrations of gamma-globulin in serum of calves receiving unfermented colostrum were higher than those of calves fed fermented colostrum at all sampling times beyond 0 h. Concentrations of gamma-globulin in serum of calves fed buffered colostrum were intermediate. Concentrations of IgG followed a similar trend. Health problems were not encountered, indicating potential for passive immunization of newborn calves via fermented, buffered colostrum in emergency situations.

Absorption↗
PubMedDate not supplied

[Effect of carbon composition of the fermented medium on the synthesis of volatile acids by the yeast Saccharomyces carlsbergensis 776].

The effect of glucose, maltose and sucrose on the synthesis of volatile oils during fermentation of model carbohydrate solutions (6, 8 and 11%) by the yeast Saccharomyces carlsbergensis 776 was studied. The composition and concentration of carbohydrates affected the build-up of volatile fatty acids during fermentation. The accumulation of biomass and volatile fraction of fatty acids reached maximum on the medium containing 11% glucose. There was a certain correlation between the biomass synthesis and accumulation of volatile fatty acids, i.e. with an increase in the biomass the content of volatile fatty acids in the medium increased. During fermentation of disaccharide solutions cell multiplication diminished and the fermentation process accelerated. Ethanol, residual sugar and acidity of fermented solutions increased with the initial concentration of carbohydrates. The pH value of the fermented must remained essentially unaltered independent of the sugar amount used.

Culture Media↗
PubMed2026

Transcriptomic shift in ethanol and amino acid metabolic genes regulated by Med15 during alcoholic fermentation.

Organisms that thrive in extreme environments provide natural experiments in evolution, revealing the genetic regulators that orchestrate complex phenotypic change. Wine yeast are specialized strains that are adapted to survive in the wine making environment while producing high concentrations of ethanol. In addition to large genomic changes that differentiate wine yeast from yeast used in other industries, single nucleotide and polyglutamine tract polymorphisms in the transcriptional regulator Med15 are associated with the fermentation efficiency and stress response phenotypes of wine yeast. In this study we investigated the transcriptional differences during wine fermentation in transgenic lab strain yeast having integrated wine yeast MED15 alleles. Compared to the unmodified lab strain (LAB or MED15 LAB ), the same strain in which the MED15 locus was replaced with a MED15 allele from yeast isolated from palm wine, the fermented sap of palm (oil, date, coconut) trees, (WY23, or MED15 WY23 ) exhibited enhanced expression of glycolytic, fermentation, and amino acid biosynthesis genes. Our experimental data confirms the importance of arginine biosynthetic genes during the fermentation process and suggests that the improvement in fermentation efficiency in strains with MED15 alleles from some wine yeast strains may be related to the role of Med15 in expression of the genes of the arginine biosynthetic pathway. The global benefit conferred by polymorphisms in a single transcriptional regulator, makes Med15 a prime target for engineering of strains devoted to various types of alcohol production.

Journal Article↗