Fermentation Supernatant Research Articles

Process optimization studies on xylanase production and bioethanol fermentation

Xylanase is one of the hydrolytic enzymes with a broad industrial application in several industries. Bioethanol can be synthesised from lignocellulosic biomass by using xylanase and other hydrolytic enzymes. A filamentous fungus, which is Aspergillus niger produces xylanase under submerged fermentation when oil palm empty fruit brunches were used as carbon sources. This study aimed to optimize the operating conditions (medium pH and incubation temperature) of xylanase production process using the OFAT analysis technique. From the data obtained, the highest xylanase production was 0.508 U/mL at pH 5.0 and 0.524 U/mL at an incubation temperature of 32°C, respectively. S. cerevisiae yeast was added into the fermentation supernatant for bioethanol fermentation. The concentration of bioethanol produced by xylanase enzyme from A. niger at optimum operating condition was 15.54±0.47 g/L. This study proved that A. niger is one of the filamentous fungi which show the potential of hydrolysing lignocellulosic material to carbon sources and subsequently to bioethanol production.

Biodiesel Production from Soybean Oil Using a Free-Enzyme and Whole-Cell Dual Lipase System as a Biocatalyst.

A dual lipase system has been developed to convert soybean oil into biodiesel through synergistic catalysis of Thermomyces lanuginosus lipase (TLL) and Yarrowia lipolytica lipase 2 (YLL) in this study. Pichia pastoris recombinant strains expressing lipases were successfully constructed, and the activities of TLL and YLL in the fermentation supernatant reached 23,142.71 ± 280.54 U/mL and 895.44 ± 27.31 U/mL, respectively. Immediately thereafter, free lipase was used to catalyze the preparation of biodiesel from soybean oil. After optimizing reaction conditions, 80 U/g oil TLL and 20 U/g oil YLL were used to catalyze the production of biodiesel, and a 95.56% biodiesel yield was obtained at 40°C, 40% moisture content (water/oil, w/w), and stepwise addition of five molar equivalents of methanol. Double lipase plasmids (tll gene and yll gene in different proportions) were constructed in vitro and introduced into P. pastoris to construct a recombinant strain with optimal activity. Under the reaction conditions of 40% moisture content, 8% whole-cell biocatalyst dosage, and stepwise addition of five molar equivalents of methanol, the biodiesel yield reached 95.35% after 24h at 40°C. These results show that synergistic catalysis is an effective strategy for biodiesel synthesis and can not only improve the biodiesel yield but also shorten the reaction time. This study provides a scientific basis for biodiesel production by multi-enzyme compounding, with potential industrial applications.

Galacto-oligosaccharides alone and combined with lactoferrin impact the Kenyan infant gut microbiota and epithelial barrier integrity during iron supplementation in vitro

Aim: Iron supplementation to African weaning infants was associated with increased enteropathogen levels. While cohort studies demonstrated that specific prebiotics inhibit enteropathogens during iron supplementation, their mechanisms remain elusive. Here, we investigated the in vitro impact of galacto-oligosaccharides (GOS) and iron-sequestering bovine lactoferrin (bLF) alone and combined on the gut microbiota of Kenyan infants during low-dose iron supplementation. Methods: Different doses of iron, GOS, and bLF were first screened during batch fermentations (n = 3), and the effect of these factors was studied on microbiota community structure and activity in the new Kenyan infant continuous intestinal PolyFermS model. The impact of different fermentation treatments on barrier integrity, enterotoxigenic Escherichia coli (ETEC) infection, and inflammatory response was assessed using a transwell co-culture of epithelial and immune cells. Results: A dose-dependent increase in short-chain fatty acid (SCFA) production, Bifidobacterium and Lactobacillus /Leuconostoc /Pediococcus (LLP) growth was detected with GOS alone and combined with bLF during iron supplementation in batches. This was confirmed in the continuous PolyFermS model, which also showed a treatment-induced inhibition of opportunistic pathogens C. difficile and C. perfringens . In all tests, supplementation of iron alone and combined with bLF did not have a significant effect on microbiota composition and activity. We observed a strengthening of the epithelial barrier and a decrease in cell death and pro-inflammatory response during ETEC infection with microbiota fermentation supernatants from iron + GOS, iron + bLF, and iron + GOS + bLF treatments compared to iron alone. Conclusion: Overall, beneficial effects on infant gut microbiota were shown using advanced in vitro models for GOS alone and combined with bLF during low-dose iron supplementation.

Study on the mechanism of lactic acid bacteria and their fermentation broth in alleviating hyperuricemia based on metabolomics and gut microbiota.

Hyperuricemia (HUA) is a metabolic disease caused by purine metabolism disorders in the body. Lactic acid bacteria (LAB) and their fermentation broth have the potential to alleviate hyperuricemia, but the potential mechanism of action is still unclear. The LAB with high inhibitory activity against xanthine oxidase (XOD) were screened out. Then the fermentation broth, fermentation supernatant and fermentation bacteria after fermentation of these LAB were administered into HUA mice, respectively. Lactobacillus reuteri NCUF203.1 and Lactobacillus brevis NCUF207.7, of which fermentation supernatant had high inhibitory activity against XOD, were screened out and administered into HUA mice. Among them, L. reuteri strain, L. reuteri fermentation broth, L. brevis fermentation broth and L. brevis fermentation supernatant could significantly reduce serum uric acid levels and inhibited the liver XOD activity in HUA mice. The GC-MS metabolomics analysis of colon contents showed that supplementation of these four substances could partially reverse the down-regulation of energy metabolism pathways such as ketone body metabolism, pyruvate metabolism and citric acid cycle in HUA mice. It could also regulate amino acid metabolism pathways such as alanine metabolism, arginine and proline metabolism, glycine and serine metabolism, and repair the disorders of amino acid metabolism caused by HUA. In addition, the intervention of L. brevis fermentation broth and L. brevis fermentation supernatant may also accelerate the catabolism of uric acid in the intestine by up-regulating the urea cycle pathway. Fecal 16S rRNA sequencing analysis showed that their intervention increased the diversity of gut microbiota in HUA mice and alleviated the gut microbiota dysregulation caused by HUA. These results indicated that the LAB and their fermentation broth may play a role in alleviating HUA by regulating intestinal metabolism and gut microbiota.

Biocontrol yeast Kurtzmaniella quercitrusa BS-AY-S1 controls postharvest green mold of citrus fruit by producing metabolites with antifungal activity

Green mold caused by Penicillium digitatum is the leading postharvest disease in citrus fruit. While chemical fungicides are commonly used for management, yeast-based biological control strategy offers a promising and eco-friendly alternative. In this study, yeast strains were isolated from citrus orchards and the strain with the best biocontrol efficacy was screened to investigate its mechanisms for controlling postharvest green mold in citrus fruit. In total, 30 yeast strains were isolated from fruits, leaves and soil of two citrus orchards. Subsequently, 8 yeast strains tested in vivo effectively inhibited green mold in citrus fruit, with Kurtzmaniella quercitrusa BS-AY-S1 achieving the best biocontrol efficacy by reducing the disease incidence (DI) by 58.33 % and lesion diameter (LD) by 73.36 % compared to the control on the 6th day. BS-AY-S1 exhibited excellent colonization ability, laying the foundation for its biocontrol efficacy. Furthermore, the antifungal properties of BS-AY-S1 metabolites were evaluated. The fermentation supernatant of BS-AY-S1 effectively inhibited the growth of P. digitatum and controlled green mold in citrus fruit. Additionally, the volatile organic compounds (VOCs) from BS-AY-S1 markedly reduced the spore germination, spore production and mycelial growth of P. digitatum, and slowing down the progression of green mold in citrus fruit. In total, 20 VOCs, including alcohols, aldehydes, esters, ethers and ketones produced by BS-AY-S1, were identified by gas chromatography-ion mobility spectrometry (GC-IMS). In conclusion, BS-AY-S1 demonstrated potential for controlling postharvest green mold in citrus fruit, with its mechanisms of action including the ability to colonize citrus fruit wounds and produce antifungal metabolites and VOCs.

Selective production of the itaconic acid-derived compounds 2-hydroxyparaconic and itatartaric acid

There is a strong interest in itaconic acid in the medical and pharmaceutical sectors, both as an anti-bacterial compound and as an immunoregulator in mammalian macrophages. Fungal hosts also produce itaconic acid, and in addition they can produce two derivatives 2-hydroxyparaconic and itatartaric acid. Not much is known about these two derivatives, while their structural analogy to itaconate could open up several applications. In this study, we report the production of these two itaconate-derived compounds. By overexpressing the itaconate P450 monooxygenase Cyp3 in a previously engineered itaconate-overproducing Ustilago cynodontis strain, itaconate was converted to its lactone 2-hydroxyparaconate. The second product itatartarate is most likely the result of the subsequent lactone hydrolysis. A major challenge in the production of 2-hydroxyparaconate and itatartarate is their co-production with itaconate, leading to difficulties in their purification. Achieving high derivatives specificity was therefore the paramount objective. Different strategies were evaluated including process parameters such as substrate and pH, as well as strain engineering focusing on Cyp3 expression and product export. 2-hydroxyparaconate and itatartarate were successfully produced from glucose and glycerol, with the latter resulting in a higher derivatives specificity due to an overall slower metabolism on this non-preferred carbon source. The derivatives specificity could be further increased by metabolic engineering approaches including the exchange of the native itaconate transporter Itp1 with the Aspergillus terreus itaconate transporter MfsA. Both 2-hydroxyparaconate and itatartarate were recovered from fermentation supernatants following a pre-existing protocol. 2-hydroxyparaconate was recovered first through a process of evaporation, lactonization, and extraction with ethyl acetate. Subsequently, itatartarate could be obtained in the form of its sodium salt by saponification of the purified 2-hydroxyparaconate. Finally, several analytical methods were used to characterize the resulting products and their structures were confirmed by nuclear magnetic resonance spectroscopy. This work provides a promising foundation for obtaining 2-hydroxyparaconate and itatartarate in high purity and quantity. This will allow to unravel the full spectrum of potential applications of these novel compounds.

Development of a non-targeted metabolomics-based screening method for elucidating the metabolic characteristics and potential applications of Lacticaseibacillus paracasei

The increasing demand for healthy foods has led to widespread interest in lactic acid bacteria due to their potential health benefits. We propose the hypothesis that Lacticaseibacillus paracasei (L. paracasei) can produce beneficial metabolites under specific conditions, which offers potential applications in functional foods. In this study, we analyzed the fermentation supernatants and brown fermented milk metabolites of L. paracasei to identify those with possible applications in functional foods, which have great potential. We found that L. paracasei IMAU32642 produced unique metabolites, including docosahexaenoic acid (DHA), leucyl phenylalanine, and oleic acid in its fermentation supernatant. Meanwhile, L. paracasei IMAU60048 exhibited unique application prospects in brown fermented milk, with higher yields of arachidonic acid and caprylic acid compared to other strains. This study offers a new and effective method for screening L. paracasei. The study can promote the development of functional foods and enhance their health value.

Antibacterial, Herbicidal, and Plant Growth-Promoting Properties of Streptomyces sp. STD57 from the Rhizosphere of Adenophora stricta.

Bacterial wilt triggered by the soil-borne pathogenic bacterium Ralstonia solanacearum is one of the most serious diseases in tomato plants, leading to huge economic losses worldwide. Biological control is considered an environmentally friendly and sustainable way to manage soil-borne diseases. In this study, Streptomyces sp. STD57 isolated from the rhizosphere of Adenophora stricta showed strong antibacterial activity against R. solanacearum. Pot experiments showed that strain STD57 exhibited a significant biocontrol effect (81.7%) on tomato bacterial wilt in the greenhouse environment. Furthermore, strain STD57 could inhibit the growth of weeds (Amaranthus retroflexus, Portulaca oleracea, and Echinochloa crusgalli) but promote the growth of crops (wheat, rice, and tomato). The plant growth-promoting substance was identified as indoleacetic acid (IAA) by high-pressure liquid chromatography-mass spectrometry and genome analysis. Coarse separation of the fermented extracts revealed that the antibacterial and herbicidal substances were mainly in the fermentation supernatant and belonged to different products. These findings suggested that strain STD57 may be a potential biocontrol and bioherbicide agent useful in agriculture.

Oriented bioconversion of food waste to lactic acid for external carbon source production: Microbial communities and comparison of denitrification performance

The lactic acid fermentation supernatant of food waste (FSFW-LA) is an excellent carbon source for denitrification regarding performance and cost. Currently, limited attention has been paid to the concentration of lactic acid and its composition in the final product. In this study, five types of liquid carbon sources were obtained under optimal conditions to ensure a high concentration and percentage of the target products. Among them, FSFW-LA reached 68.1 g/L (81.8 %, w/w) of lactic acid by oriented bioconversion and possessed denitrification parameters closest to sodium acetate. Under the combined long-term operation of the SBR system with domestic wastewater, the TN and COD removal in the effluent after the addition of FSFW-LA stabilized at 96 % and 84 %, respectively, similar to sodium acetate (96 % and 85 %). Overall, the denitrification capabilities of high-quality FSFW-LA were explored, providing details on economic carbon source production.

Whole-genome sequencing and assessment of a novel protein- and gossypol-degrading Bacillus subtilis strain isolated from intestinal digesta of Tibetan Pigs

BackgroundWith the rapid development of animal husbandry, the demand for protein feed resources is increasing. Cottonseed meal (CSM) and soybean meal (SBM) are rich sources of protein. However, their application is limited due to the existence of anti-nutrients, which can be harmful to the digestion and absorption. A strain of Bacillus subtilis (Mafic-Y7) was isolated from digesta of intestines of Tibetan pigs. The strain showed high protease activity, which helps in degrading proteinic anti-nutritional factors in grain meal and in vitro degradation of free gossypol. In order to better understand this isolated strain, whole genome of Mafic-Y7 strain was sequenced and analyzed. Different effects on various grain meals were identified.ResultThe GC-depth Poisson distributions showed no bias suggesting high-quality genome assembly of Mafic-Y7. The whole genome sequencing showed that one chromosome with 4,248,845 base pairs(bp)and the genes total length with 3,736,524 bp was predicted in Mafic-Y7. Additionally, Mafic-Y7 possessed 4,254 protein-coding genes, and several protease genes were annotated by aligning them with databases. There are 55 protease genes, one phytase gene and one laccase gene were annotated in the gene sequence of Mafic-Y7. The average nucleotide identity between Mafic-Y7 and the GCA-000009045.1 homologous genome was 0.9938, suggesting a close genetic relationship between them at the species level. Compared with the closest four whole genomes, Mafic-Y7 was annotated the most abundant of protease genes (55 genes). The fermentation supernatant of Mafic-Y7 could increase the content of small peptides, water-soluble proteins, and acid-soluble proteins in vitro by 411%, 281% and 317% in SBM and 420%, 257% and 338% in CSM. After fermentation in grain meal by Mafic-Y7, the degradation rate of anti-nutritional factors in SBM, such as trypsin inhibitor, glycinin, and β-conglycinin was greater than 70%, and lectin was greater than 30%. The degradation rates of anti-nutritional factors in CSM, such as gossypol and phytic acid, were 82% and 26%, respectively.

Manufacturing of the highly active thermophile PETases PHL7 and PHL7mut3 using Escherichia coli

BackgroundThe global plastic waste crisis requires combined recycling strategies. One approach, enzymatic degradation of PET waste into monomers, followed by re-polymerization, offers a circular economy solution. However, challenges remain in producing sufficient amounts of highly active PET-degrading enzymes without costly downstream processes.ResultsUsing the growth-decoupled enGenes eX-press V2 E. coli strain, pH, induction strength and feed rate were varied in a factorial-based optimization approach, to find the best-suited production conditions for the PHL7 enzyme. This led to a 40% increase in activity of the fermentation supernatant. Optimization of the expression construct resulted in a further 4-fold activity gain. Finally, the identified improvements were applied to the production of the more active and temperature stable enzyme variant, PHL7mut3. The unpurified fermentation supernatant of the PHL7mut3 fermentation was able to completely degrade our PET film sample after 16 h of incubation at 70 °C at an enzyme loading of only 0.32 mg enzyme per g of PET.ConclusionsIn this research, we present an optimized process for the extracellular production of thermophile and highly active PETases PHL7 and PHL7mut3, eliminating the need for costly purification steps. These advancements support large-scale enzymatic recycling, contributing to solving the global plastic waste crisis.

Enhancing selective NH4+ recovery from wastewater using modified zeolite-based flow electrode capacitive deionization

Despite flow-electrode capacitive deionization (FCDI) is an emerging technology for desalination, contaminant removal, and resource recovery, the application of conventional FCDI in wastewater treatment is hindered by the electrode selectivity and material costs. In this study, we synthesized a low-cost ammonium (NH4+) adsorption electrode material by modifying zeolite using ethylenediaminetetraacetic acid disodium salt (EDTA-2Na). The flow electrode prepared by the mixture of EDTA-zeolite and carbon black exhibits a high selectivity and adsorption capacity for the recovery of NH4+ from wastewater. The NH4+ in wastewater passes through the ion exchange membrane and is rapidly adsorbed by the modified zeolite through ion exchange, while Na+ is retained in the electrolyte. The decrease in NH4+ concentration and the increase in Na+ concentration in the catholyte lead to a significant change in ion concentration gradient across the membrane. Consequently, the transmembrane selectivity between NH4+ and Na+ reached 3.46. We validated the feasibility of NH4+ recovery using FCDI with food waste fermentation supernatant. Under optimal operating conditions, 99.15 % of the NH4+ in the fermentation supernatant was removed, and 95.92 % of the NH4+ in the electrolyte was stored in the EDTA-zeolite. By gravitational settling, the NH4+-rich modified zeolite was separated from carbon black and could be utilized as nitrogen fertilizer. Meanwhile, the mixture of carbon black and brine was used to prepare a fresh electrode suspension. In brief, the FCDI system exhibits a satisfying NH4+ recovery performance and demonstrates a sustainable wastewater resource recovery strategy.

Isolation of a novel Bacillus subtilis HF1 strain that is rich in lipopeptide homologs and has strong effects on the resistance of plant fungi and growth improvement of broilers.

Bacillus subtilis is an important probiotic microorganism that secretes a variety of antimicrobial compounds, including lipopeptides, which are a class of small molecule peptides with important application value in the fields of feed additives, food, biopesticides, biofertilizers, medicine and the biological control of plant diseases. In this study, we isolated a novel B. subtilis HF1 strain that is rich in lipopeptide components and homologs, has a strong antagonistic effect on a variety of plant fungi, and is highly efficient in promoting the growth of broilers. The live B. subtilis HF1 and its fermentation broth without cells showed significant inhibitory effects on 20 species of plant fungi. The crude extracts of lipopeptides in the fermentation supernatant of B. subtilis HF1 were obtained by combining acid precipitation and methanol extraction, and the lipopeptide compositions were analyzed by ultrahigh-performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). The results showed that HF1 could produce 11 homologs of surfactin and 13 homologs of fengycin. Among the fengycin homologs, C13-C19 fengycin A and C15-C17 fengycin B were identified; among the surfactin homologs, C11-C17 surfactin A and C13-C16 surfactin B were characterized. C13 fengycin A, C11 surfactin A and C17 surfactin A were reported for the first time, and their functions are worthy of further study. In addition, we found that HF1 fermentation broth with and without live cells could be used as a feed additive to promote the growth of broilers by significantly increasing body weight up to 15.84%. HF1 could be a prospective strain for developing a biocontrol agent for plant fungal diseases and an efficient feed additive for green agriculture.

Screening and identification of Paenibacillus polymyxa GRY-11 and its biological control potential against apple replant disease.

Apple replant disease (ARD) is a significant factor restricting the healthy development of the apple industry. Biological control is an important and sustainable method for mitigating ARD. In this study, a strain of Paenibacillus polymyxa GRY-11 was isolated and screened from the rhizosphere soil of healthy apple trees in old apple orchards in Shandong Province, China, and the effects of strain GRY-11 on soil microbial community and ARD were studied. The result showed that P. polymyxa GRY-11 could effectively inhibit the growth of the main pathogenic fungi that caused ARD, and the inhibition rates of the strain against Fusarium moniliforme, Fusarium proliferatum, Fusarium solani, and Fusarium oxysporum were 80.00%, 71.60%, 75.00%, and 70.00%, respectively. In addition, the fermentation supernatant played an active role in suppressing the growth of pathogenic fungi. The results of the pot experiment showed that the bacterial fertilizer of the GRY-11 promoted the growth of Malus hupehensis seedlings, improved the activity of protective enzymes in plant roots, enhanced the soil enzyme content, and optimized the soil microbial environment. In general, the GRY-11 can be used as an effective microbial preparation to alleviate ARD. Our study offers novel perspectives for the prevention of ARD.

Evaluation of Functional Components of Lactobacillus plantarum AR495 on Ovariectomy-Induced Osteoporosis in Mice And RAW264.7 Cells

Osteoporosis is a disease characterized by abnormal bone metabolism, where bone resorption outpaces bone formation. In this study, we investigated the key functional components of Lactobacillus plantarum AR495 in mitigating ovariectomy (OVX)-induced osteoporosis in mice. The results indicated that both Lactobacillus plantarum AR495 and its fermentation broth significantly reduced urinary calcium and deoxypyridinoline (DPD) levels in the mice. These interventions inhibited bone resorption and improved trabecular bone architecture by modulating the nuclear factor κB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) signaling pathway. Additionally, the L. plantarum AR495 and fermentation broth groups inhibited the RANKL/TRAF-6 and TLR4/MYD88 pathways, leading to enhanced bone metabolism, improved intestinal barrier function, and reduced intestinal inflammation. In vitro experiments revealed that AR495 fermentation supernatant fractions larger than 100 kDa and those between 50–100 kDa significantly decreased the activity of the osteoclast marker TRAP, regulated the expression of the TLR4/MYD88 pathway, and inhibited osteoclast formation, thereby alleviating the OVX-induced osteoporosis phenotype. These findings suggest that these components may be primary functional elements of L. plantarum AR495 in the treatment of osteoporosis.

A novel high-level phenyllactic acid fungal producer, Kodamaea ohmeri w5 screened from fermented broad bean-chili-paste

Phenyllactic acid (PLA) is a broad-spectrum and efficient antimicrobial phenolic acid with potential applications in the food industry. Previous studies have demonstrated that fungi may be ideal producers of PLA. In this study, 15 fungi screened from Doubanjiang with the ability to produce PLA were first reported, including Wickerhamomyces anomalus, Candida etchellsii, Candida parasitosis, Pichia kudriavzevii, Pichia membranifaciens and Kodamaea ohmeri. Among them, K. ohmeri w5 had the highest PLA yield, producing up to 7160 mg/L PLA in shake flask fermentation with phenylalanine as substrate, which was more than ten times higher than the PLA produced by wild-type LAB under the similar conditions. In addition, K. ohmeri w5 was able to grow under extreme hypertonic conditions of 20 % NaCl (w/v) and 50 % glucose (w/v) as well as produce 57.12 ± 0.42 and 1609.22 ± 36.26 mg/L of PLA, respectively. Furthermore, the fermentation supernatant of K. ohmeri w5 demonstrated direct inhibitory effects against foodborne pathogenic microorganisms, Aspergillus flavus and Bacillus cereus. However, the inhibitory effect was weaker than that of the PLA standard at the same concentration. Further, 12,497,932 bp of w5 genome-wide information was obtained by sequencing and assembling. And its gene model was predicted based on transcriptomic evidence, which showed that a total of 7 genes related to PLA synthesis were identified in the w5 genome. Based on qRT-PCR, structure prediction, and molecular docking, a potentially key genetic resource from K. ohmeri w5 for PLA production was uncovered. The results will provide novel producers of PLA and its potential genetic resources.

The prebiotic effects of fructooligosaccharides enhance thegrowth characteristics of Staphylococcus epidermidis and enhance the inhibition of Staphylococcus aureus biofilm formation.

Oligosaccharides have been shown to enhance the production of short chain fatty acids (SCFAs) by gut probiotics and regulate gut microbiota, to improve intestinal health. Recent research indicates that oligosaccharides may also positively impact skin microbiota by selectively promoting the growth of skin commensal bacteria and inhibiting pathogenic bacteria. However, the specific metabolic and regulatory mechanisms of skin commensal bacteria in response to oligosaccharides remain unclear. This study aims to explore the influence of four oligosaccharides on the growth and metabolism of Staphylococcus epidermidis and further identify skin prebiotics that can enhance its probiotic effects on the skin. Fructooligosaccharides (FOS), isomaltooligosaccharide (IMO), galactooligosaccharides (GOS) and inulin were compared in terms of their impact on cell proliferation, SCFAs production of S. epidermidis CCSM0287 and the biofilm inhibition effect of their fermentation supernatants on Staphylococcus aureus CCSM0424. Furthermore, the effect of FOS on S. epidermidis CCSM0287 was analysed by the transcriptome analysis. All four oligosaccharides effectively promoted the growth of S. epidermidis CCSM0287 cells, increased the production of SCFAs, with FOS demonstrating the most significant effect. Analysis of the SCFAs indicated that S. epidermidis CCSM0287 predominantly employs oligosaccharides to produce acetic acid and isovaleric acid, differing from the SCFAs produced by gut microbiota. Among the four oligosaccharides, the addition of 2% FOS fermentation supernatant significantly inhibited S. aureus CCSM0424 biofilm formation. Furthermore, RNA sequencing revealed 162 differentially expressed genes (84 upregulated and 78 downregulated) of S. epidermidis CCSM0287 upon FOS treatment compared with glucose treatment. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis highlighted differences in the amino acid synthesis pathway, particularly in terms of arginine biosynthesis. FOS promotes cell proliferation, increases the SCFA production of S. epidermidis CCSM0287 and enhance the inhibition of S. aureus biofilm formation, suggesting that FOS serves as a potential prebiotic for strain S. epidermidis CCSM0287.

Lactiplantibacillus plantarum P470 Isolated from Fermented Chinese Chives Has the Potential to Improve In Vitro the Intestinal Microbiota and Biological Activity in Feces of Coronary Heart Disease (CHD) Patients.

Traditional fermented foods are known to offer cardiovascular health benefits. However, the potential of fermented Chinese chives (FCC) in reducing coronary heart disease (CHD) remains unclear. This study employed anaerobic fermentation to investigate Lactiplantibacillus plantarum (L. plantarum) P470 from FCC. The results indicated that L. plantarum P470 enhanced hydroxyl radical scavenging and exhibited anti-inflammatory effects on RAW264.7 macrophages in the fecal fermentation supernatant of CHD patients. These effects were attributed to the modulation of gut microbiota and metabolites, including short-chain fatty acids (SCFAs). Specifically, L. plantarum P470 increased the abundance of Bacteroides and Lactobacillus while decreasing Escherichia-Shigella, Enterobacter, Veillonella, Eggerthella, and Helicobacter in CHD patient fecal samples. Furthermore, L. plantarum P470 regulated the biosynthesis of unsaturated fatty acids and linoleic acid metabolism. These findings suggest that L. plantarum P470 from FCC can improve the fecal physiological status in patients with CHD by modulating intestinal microbiota, promoting SCFA production, and regulating lipid metabolism.

Lactiplantibacillus plantarum ZJ316 alleviates the oxidative stress and cellular apoptosis via modulating Nrf2/HO-1 signaling pathway

Oxidative stress is vital in gastrointestinal diseases, but how lactic acid bacteria protect human gastric adenocarcinoma cells (AGS) is unclear. Here, we aimed to investigate Lactiplantibacillus plantarum ZJ316 (L. plantarum ZJ316) for its potential to alleviate oxidative stress in AGS cells and elucidate mechanisms involved. Treatment with L. plantarum ZJ316 and fermentation supernatant (ZJ316 FS) bolstered cell viability under hydrogen peroxide (H2O2)-induced oxidative stress, boosting antioxidant enzymes like superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) while reducing reactive oxygen species (ROS) and malondialdehyde (MDA). Oral probiotics also alleviated oxidative damage from D-galactose in mice. Additionally, L. plantarum ZJ316 and ZJ316 FS alleviated H2O2-induced inflammation and apoptosis by modulating the expression of inflammatory and apoptotic factors. However, the protective effect was hindered when pretreated with the Nrf2 inhibitor ML385. These findings suggest that L. plantarum ZJ316 and fermentation supernatant alleviate oxidative damage by activating the Nrf2/HO-1 pathway, showing promise in development of antioxidant functional foods.

Enhanced algin oligosaccharide production through selective breeding and optimization of growth and degradation conditions in Cobetia sp. cqz5-12-M1

Algin oligosaccharides have been applied in diverse industries and could be innovative synthesized by alginate-degrading bacteria. For enhance the alginate degradation efficiency to produce more algin oligosaccharides, a mutant strain (Cobetia sp. cqz5-12-M1) was obtained through the complex mutagenesis using UV and the alkylating agent 1-methyl-3-nitro-1-nitrosoguanidine. The enzyme activity of the fermentation supernatant of mutant exhibited a significant 38.09% (53.98 ± 0.69 U/mL) increase, and its optimal growth conditions were determined as: 5 g/L sodium alginate, 5 g/L yeast powder, 30 g/L NaCl, 2 g/L K2HPO4, 2 g/L KH2PO4, 1 g/L MgSO4•7H2O, 0.01 g/L FeSO4•7H2O, pH 6.5, and 34 ℃. Moreover, its optimal degradation conditions were identified as: 5 g/L sodium alginate, 5 g/L yeast powder, 30 g/L NaCl, 2 g/L K2HPO4, 2 g/L KH2PO4, 1 g/L MgSO4•7H2O, 0.01 g/L FeSO4•7H2O, pH 6.5, 31 ℃ and 72 h, yielding an enzyme activity of 120.98 ± 1.40 U/mL in the fermentation supernatant. Conclusive experiments on reagent tolerance revealed the growth of the mutant strain was significantly inhibited by 3% hydrogen peroxide, 5% carbolic acid, and 10 mg/mL gatifloxacin. Additionally, the alginate degradation capacity of mutant strain was highly significantly inhibited by 75% ethanol and all tested antibiotics.