Search Results (2,594)

The sesquiterpene β-caryophyllene (BCP) is a major component of various plant essential oils, to which it confers a unique spicy aroma. It is mainly used as a fragrance additive in the food, cosmetic and perfume industries, with an annual consumption ranging between 100 and 1000 metric tons worldwide. Recently, BCP has attracted attention as a promising precursor for the production of high-density fuels and for its various biological activities and pharmacological effects. These include antioxidant, anti-inflammatory, anticancer, immune–modulatory, and many other activities. Due to its underlying mechanisms, β-caryophyllene interacts with various human receptors, including CB2 of the endocannabinoid system, which defines it as a phytocannabinoid with therapeutic potential for certain serious conditions. Due to β-caryophyllene’s high utility, various green and sustainable strategies for its production in microorganisms have been developed. This article provides an update on the state-of-the-art in this field to identify directions for further development to extend the compound’s potential. Full article

Catalase (CAT) is an enzyme involved in the first line of cellular antioxidant defense. It plays a key role in the protection of a wide range of Antarctic organisms against cold stress. Extracellular catalase is very rare and data on it are extremely scarce. The aim of the present study was to select an efficient producer of extracellular catalase from amongst Antarctic filamentous fungi. Sixty-two Antarctic filamentous fungal strains were investigated for their potential ability to synthesize intracellular and extracellular CAT. The Antarctic strain Penicillium rubens III11-2 was selected as the best producer of extracellular catalase. New information on the involvement of the extracellular antioxidant enzymes superoxide dismutase and CAT in the response of filamentous fungi against low-temperature stress was obtained. An efficient scheme for the purification of CAT from culture fluid was developed. An enzyme preparation with high specific activity (513 U/mg protein) was obtained with a yield of 19.97% and a purification rate of 98.4-fold. The purified enzyme exhibited maximal enzymatic activity in the temperature range of 5–40 °C and temperature stability between 0 and 30 °C, therefore being characterized as temperature sensitive. To our knowledge, this is the first purified extracellular cold active catalase preparation from Antarctic filamentous fungi. Full article

Fermented beverages have been a constant companion of humans throughout their history. A wide range of products have been developed with time, depending on the availability of raw materials and ambient conditions. Their differentiation was based on the specific characteristics of each product, resulting from the cultivation of different varieties and the variability of environmental conditions and agricultural practices, collectively described by the term ‘terroir’ that was developed in winemaking. The health benefits that have been associated with their consumption, which include the control of blood pressure and glycemic control, along with immunomodulatory, hypocholesterolemic, hepatoprotective, and antiproliferative activities, directed their re-discovery that occurred over the last few decades. Thus, the dynamics of the microbial communities of fermented beverages during fermentation and storage have been thoroughly assessed. The functional potential of fermented beverages has been attributed to the chemical composition of the raw materials and the bioconversions that take place during fermentation and storage, due to the metabolic capacity of the driving microbiota. Thus, the proper combination of raw materials with certain microorganisms may allow for the modulation of the organoleptic properties, as well as enrichment with specific functional ingredients, enabling targeted nutritional interventions. This plasticity of fermented beverages is their great advantage that offers limitless capabilities. The present article aims to critically summarize and present the current knowledge on the microbiota and functional potential of fermented beverages and highlight the great potential of these products. Full article

Amino alcohols are important compounds that are widely used in the polymer and pharmaceutical industry, particularly when used as chiral scaffolds in organic synthesis. The hydroxylation of polyamide polymers may allow crosslinking between molecular chains through the esterification reactions of hydroxyl and carboxyl groups. Therefore, this may alter the functional properties of polyamide polymers. 2-hydroxycadaverine (2HyC), as a new type of chiral amino alcohol, has potential applications in the pharmaceutical, chemical, and polymer industries. Currently, 2HyC production has only been realized via pure enzyme catalysis or two-stage whole-cell biocatalysis, which faces great challenges for scale-up production. However, the use of a cell factory is very promising for the production of 2HyC in industrial applications. Here, we designed and constructed a promising artificial pathway in Escherichia coli for producing 2HyC from biomass-derived lysine. This biosynthesis route expands the lysine catabolism pathway and employs two enzymes to sequentially convert lysine into 2HyC. However, the catalytic activity of wild-type pyridoxal phosphate-dependent decarboxylase from Chitinophage pinensis (DC_Cp) toward 3-hydroxylysine is lower, resulting in the lower production of 2HyC. Thus, the higher catalytic activity of DC_Cp is desired for low-cost and expanded industrial applications of 2HyC. To improve the catalytic activity of DC_Cp, a mutant library of DC_Cp was first built using a semi-rational design. The K_cat/K_m of mutant DC_Cp (R53D/V94I) increased by 63%. A titer of 359 mg/L 2HyC was produced in shake flasks, with a 2HyC titer increase of 54% compared to control strain ML101. The results show that the production of 2HyC was effectively increased through a semi-rational design strategy. These findings lay the foundation for the development and utilization of renewable resources to produce 2HyC in microorganisms via an efficient, green, and sustainable biosynthetic strategy for further industrial application. Full article

Soy leghemoglobin (LegH) has been gaining interest over the last years as an efficient flavor and aroma compound in plant-based meat substitutes. Hence, in the following article, we demonstrate the methods for LegH production using a recombinant Komagataella phaffii strain. Multiple fed-batch fermentation with an alternative to a BSM medium, where glucose was used as the main carbon source, was implemented and the growth kinetics, e.g., a maximal specific biomass growth of 0.239 g·g⁻¹·h⁻¹, a biomass yield from the substrate of 0.298 g·g⁻¹, and a maximal specific substrate consumption rate of 0.81 g·g⁻¹·h⁻¹ were identified. Leghemoglobin production resulted in a yield of 0.513 mg·gDCW⁻¹, while the highest biomass density achieved in this study was 121.80 gDCW·L⁻¹. The applied medium that showed potential for additional optimization studies, which, in contrast to BSM, made it possible to separate pH control from nitrogen supply, does not affect medium turbidity measurements and does not induce metabolite synthesis during yeast biomass growth. Full article

Brewer’s spent yeast (BSY) is one of the brewing industry’s most plentiful side-streams. Abundant, low-cost and high in nutrients, it has great potential for application in food technology and human nutrition. With the ever-increasing interest in sustainability, waste reduction and circular food systems, the use of BSY as a novel food ingredient may be the route to add exponential value while reducing the environmental impact. However, negative flavour characteristics and high amounts of alcohol severely limit the current applications of BSY. This study explores the use of processing involving lactic acid bacteria (LAB) fermentation technology as a means of improving BSY quality characteristics and examines the effects of this process on the chemical, nutritional and sensory characteristics of BSY. The results reveal that BSY is a suitable substrate for LAB fermentation, successfully supporting the growth of Lactobacillus amylovorus FST 2.11. Compared to the unfermented BSY (CBSY), fermentation significantly reduced the perceptible bitterness of the BSY as detected by a sensory panel, from 6.0 ± 2.8 units to 0.9 ± 0.7 units, respectively. Fermented BSY (PBSY) had enhanced sour and fruity flavours, and a variety of other volatile compounds and metabolites were determined. Protein profiles showed significant protein degradation, and free amino acid levels were greatly increased following fermentation, from 2.8 ± 0.2 g/100 g to 10.5 ± 0.4 g/100 g, respectively. Protein quality was high, with the CBSY and PBSY providing well over the required level (>100%) of essential amino acids per gram protein, with the exception of sulphur amino acids (98%). Major physical differences were observed using scanning electron microscopy. This study concludes that LAB fermentation positively affects the sensory and nutritional characteristics of BSY and can aid in the incorporation of brewer’s spent yeast into foods for human consumption. Full article

Fermented foods such as table olives are produced through a spontaneous process that has been improved over the years, ensuring the safety and quality of the final product. The aim of the present work was to study the action of starter cultures of lactic acid bacteria (Lacticaseibacillus rhamnosus GG ATCC53103, Levilactobacillus brevis ATCC8287, and Lactiplantibacillus plantarum ATCC14917) which were previously shown to have probiotic and antioxidant potential during the fermentation of natural Greek-style black olives (Kalamata) in brine containing 6% (w/v) NaCl at a temperature of 20 °C for a period of 150 days. At a molecular level, the main metabolites in every fermentation process were identified using an HPLC method. The results showed that the concentration of the metabolites increased gradually, developing a stable pattern after the 90th day of fermentation. In addition, the DL-p-hydroxyphenyllactic acid (OH-PLA) was identified as the phenolic acid with the highest concentration, independently of the selected starter culture. Microbial genomic DNA was also extracted from the olives’ surface at the final stages of fermentation (150 days) and was subjected to 16S rRNA sequencing using the Nanopore MinION™ NGS tool, enabling a comprehensive analysis of the microbial community. According to the findings, the most abundant genera were Lactobacillus and Leuconostoc. To the best of our knowledge, this is the first study exploring these particular starters for olive fermentation. Full article

Malolactic fermentation (MLF) in wine is driven by the lactic acid bacterium Oenococcus oeni in most cases. Although this bacterium is resistant to wine stress conditions, it often faces difficulties completing MLF. Previous studies indicate that yeast mannoproteins may improve O. oeni growth and survival in wine. However, very little is known about this topic. This study evaluated the effect of the addition of mannoprotein extracts to culture media on O. oeni growth and its survival to stress conditions and MLF performance. Three commercial mannoprotein extracts were characterized in terms of polysaccharide and protein richness and were used for O. oeni culture media supplementation. The addition of mannoprotein extracts improved the survival of the two evaluated O. oeni strains, PSU-1 and VP41, after acid shock (pH 3.2) in comparison to that of the control. The transcriptional response of four genes involved in mannose metabolism was different depending on the strain, indicating the complexity of sugar metabolism in O. oeni. PSU-1 cells grown with two of the mannoprotein extracts performed faster MLF compared with the control condition, indicating that mannoprotein addition may improve the performance of O. oeni starter cultures, although this effect depends on the strain. Full article

Saccharomyces cerevisiae var. boulardii (Sb) is currently receiving significant attention as a synthetic probiotic platform due to its ease of manipulation and inherent effectiveness in promoting digestive health. A comprehensive exploration of Sb and other S. cerevisiae strains (Sc) would shed light on the refinement and expansion of their therapeutic applications. This review aims to provide a thorough overview of Saccharomyces yeasts from their native health benefits to recent breakthroughs in the engineering of Saccharomyces yeasts as synthetic therapeutic platforms. Molecular typing and phenotypic assessments have uncovered notable distinctions, including the superior thermotolerance and acid tolerance exhibited by Sb, which are crucial attributes for probiotic functions. Moreover, parabiotic and prebiotic functionalities originating from yeast cell wall oligosaccharides have emerged as pivotal factors influencing the health benefits associated with Sb and Sc. Consequently, it has become imperative to select an appropriate yeast strain based on a comprehensive understanding of its actual action in the gastrointestinal tract and the origins of the targeted advantages. Overall, this review underscores the significance of unbiased and detailed comparative studies for the judicious selection of strains. Full article

Representatives of the genus Bacillus have been established as one of the most important industrial microorganisms in the last few decades. Genetically modified B. subtilis and, to a lesser extent, B. licheniformis, B. amyloliquefaciens, and B. megaterium have been used for the heterologous expression of numerous proteins (enzymes, vaccine components, growth factors), platform chemicals, and other organic compounds of industrial importance. Vectors designed to work in Bacillus spp. have dramatically increased in number and complexity. Today, they provide opportunities for genetic manipulation on every level, from point mutations to systems biology, that were impossible even ten years ago. The present review aims to describe concisely the latest developments in the shuttle, integrative, and CRISPR-Cas9 vectors in Bacillus spp. as well as their application for large-scale bioengineering with the prospect of producing valuable compounds on an industrial scale. Genetic manipulations of promoters and vectors, together with their impact on secretory and metabolic pathways, are discussed in detail. Full article

Lactic acid bacteria effectively utilize the nutrients and active compounds in plant-based materials via their powerful metabolic pathways and enzyme systems, achieving a combination of nutrition, functionality, and deliciousness. Currently, the majority of review articles predominantly concentrate on summarizing the fermentation of fruits and vegetables by lactic acid bacteria, devoting comparatively less attention to researching other plant species varieties and plant-based by-products. Furthermore, the summary of the research on the active substances and functional properties lacks sufficient depth. This review provides a comprehensive overview of the status of and technological progress in lactic acid bacteria fermentation of various plant species and plant-based by-products, and the effects of lactic acid bacteria on the active substances and functional properties are emphasized. In addition, this review emphasizes that active substances give products more functionality. The aim of this review is to emphasize the significant contribution of lactic acid bacteria to the active substances and functional properties of plant-based products, which will assist researchers in better comprehending the application value of lactic acid bacteria in the plant-based domain and direct attention towards the interaction mechanisms between active substances and product functionality. Concurrently, this review provides a certain theoretical foundation and reference for the application of fermented functional products in promoting health and preventing diseases. Full article

In recent years, probiotics have received considerable attention for improving the health of aquaculture organisms, such as fish and shrimp, by stimulating immune activity and increasing growth rates. Oplegnathus fasciatus is a common and economically important cultured fish species in Asia. In this study, we aimed to investigate the potential of lactic acid bacteria (LAB; Limosilactobacillus reuteri)-fermented feed to promote growth and enhance immune function in O. fasciatus. The feed contained the highest proportion of LAB after L. reuteri fermentation for 3 days in anaerobic conditions. Oplegnathus fasciatus was fed LAB-fermented feed for 30 days. The administration of LAB-fermented feed (live bacteria > 10⁹ CFU/g) significantly increased the growth rate (weight gain = 174.8%; FCR = 4.23) and intestinal probiotic levels of O. fasciatus. After LAB-fermented feeding, the immunity index was evaluated by superoxide anion production, the phagocytic activity of leukocytes, and bactericidal and lysozyme activities in the serum of O. fasciatus. We found that LAB-fermented feed treatment potentially elevated the proportions of intestinal Bifidobacterium, Blautia, and Dorea species and reduced pathogenic bacterial growth (Acinetobacter, Escherichia_Shigella, and Megasphaera) in O. fasciatus. This study demonstrated that LAB-fermented feed containing extracellular vesicles improves growth performance and the inhibition of pathogenic Acinetobacter baumannii. Full article

Improper disposal of vegetable waste can cause serious environmental pollution, but because they contain huge water content and organic matter, they are not suitable for disposal by methods such as incineration and landfill. However, vegetable waste contains a large amount of nutrients and have some complementary effects with rice straw in terms of physical structure, nutrients, and moisture. In this experiment, the plant feed (corn husk, peanut shells and sorghum shells) was used as the control group (CON group), and the mixed silage of Chinese cabbage waste and rice straw (mixed silage) was used as the experiment group (TRE group), and its safety performance was evaluated by testing its toxin content, pesticide residues, vitamin contents and feeding experiment of Hu sheep. In the animal experiment, 16 healthy Hu sheep (5.5 months, 39.11 ± 4.16 kg) were randomly divided into two groups of 8 each. The results of the safety performance evaluation showed that the content of mycotoxins, heavy metals, and nitrites as well as pesticide residues in the crude feeds of both groups were within the range of Chinese feed hygiene standards. In addition, the levels of deoxynivalenol (DON) and aflatoxin (AFT) in the CON group were lower, while the content of ochratoxin (OTA) and zearalenone were higher than those in the TRE group (p < 0.05). The levels of plumbum(Pb), chromium (Cr), cadmium (Cd), and nitrite in the CON group were lower than the mixed silage, while the levels of As were higher than the mixed silage (p < 0.05). It is worth noticing that the content of vitamin B₂ (VB₂) and vitamin C (VC) in the TRE group was higher than the CON group (p < 0.05). The results of the feeding experiment showed that the mixed silage did not affect the growth performance, nutrient digestibility, organ index, and intestinal index of Hu sheep (p > 0.05). In addition, the mixed silage reduced the weight of omasum, the proportion of omasum to live weight before slaughter, the amount of compound stomach, and the proportion of compound stomach to live weight before slaughter, which were higher than those in the TRE group (p < 0.05). The thickness of the basal layer of the rumen abdominal sac, the red blood cell count, the content of IL-10, and TNF-α in the blood, and TNF-α content in the rumen of the Hu sheep in the TRE group were higher than the CON group (p < 0.05). In conclusion, the feed safety index content of the mixed silage did not exceed the Chinese feed hygiene and safety standards and did not cause adverse effects on the growth performance of the Hu sheep, and it improved the immune performance of the body and digestive tract of the sheep to a certain extent and promoted the healthy development of the sheep. Full article

Morchella esculenta is a precious edible and medicinal fungus rich in protein, polysaccharides, polyphenols, amino acids, triterpenes, and other active components. In this study, MS-1 was isolated from the fruiting body of M. esculenta. Through conducting single-factor experiments and the response surface analysis of the culture conditions, the optimal culture components of an M. esculenta fermentation broth for extracellular polysaccharide production were determined, namely, 3.7% glucose, 2% yeast extract, and 0.15% sodium chloride. The polysaccharides MSF and MSL were extracted from the fruiting body of M. esculenta and the fermentation broth, respectively, and analyzed with gel permeation chromatography (GPC), monosaccharide composition, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and in vivo and in vitro antioxidant and anti-inflammatory activity analyses. The research results show that the calculated MW of MSF is 2.34 × 10⁵ Da, and the calculated MW of MSL is 1.40 × 10⁵ Da. MSF is composed of three monosaccharides: D-galactose, D-glucose, and D-mannose (molar ratio of 4.34:90.22:5.45). MSL consists of five monosaccharides: D-arabinose, D-galactose, D-glucose, D-mannose, and glucuronic acid (molar ratio of 0.31:14.71:13.03:71.43:0.53). The in vitro antioxidant test results show that MSF and MSL both have significant antioxidant activities. Activity experiments on MSF and MSL in zebrafish showed that MSF and MSL have significant repair effects on the oxidative damage caused by metronidazole in zebrafish embryos, and there were significant changes in the transcriptional activity levels of the oxidative stress-related genes SOD, Keap1, and Nrf2. Therefore, the polysaccharides MSF and MSL from MS-1 can be used as important raw materials for functional foods and drugs. Full article