ABSTRACT Microbial exopolysaccharides (EPS) extracted from probiotic microorganisms have recently garnered considerable attention due to their wide applicability in food and pharmaceutical industries. EPS have gained attention as they are nontoxic, biocompatible and biodegradable. In this study, eight potential probiotic isolates have been isolated from traditional fermented bamboo shoots of North East India. Of the eight isolates, the isolate identified as Bacillus subtilis BB2 produced the highest amount of EPS. The monosaccharide composition analysis of the extracted EPS revealed fructose as its main component. The FT-IR spectrum identified functional groups present in the extracted EPS. Thermo gravimetric and differential scanning calorimetric analysis revealed that the EPS remained stable up to 200°C. It also exhibited significant free-radical-scavenging activity in vitro. Also, extracted EPS showed antibiofilm activity against selected bacterial pathogens. These findings indicate that the EPS produced from probiotic Bacillus subtilis BB2 hold promising potential as a natural alternative for food and wider industrial applications.

ABSTRACT The study evaluated the prebiotic potential of polyphenols from finger millet seed coat (FMSC) on lactic acid bacteria (LAB) and in turn the biotransformation of polyphenols by the action of probiotic bacteria. In vitro fermentation studies in terms of growth kinetics of LAB, prebiotic activity score (PAS), production of short chain fatty acids (SCFAs) and the changes in phenolic contents during fermentation were assessed by GC-MS and HPLC. FMSC polyphenols were efficiently utilized by the probiotic strains evident from the maximal growth rate in the logarithmic phase, among the strains, L. plantarum showed highest growth. A sharp drop in pH was recorded, a characteristic feature of LAB. SCFAs were produced in varying quantities. Phenolic monomers and aglycones appeared after probiotic fermentation. The study substantiates the bi-directional metabolism of FMSC polyphenols and LAB, which paves way for the development of functional foods that render potential health benefits to consumers.

ABSTRACT The aim of this study was to evaluate the possibility of improving the intestinal environment by reducing intestinal pathogens, Staphylococcus aureus and Escherichia coli, using the three Levilactobacillus brevis strains (L. brevis KU202399, L. brevis B151, and L. brevis KU15006) isolated from kimchi. We confirmed the characteristics of the probiotics and the safety of the L. brevis strains. Also, we examined the antibacterial effects, cell surface properties, anti-adhesion ability, and expression of antibiotic resistance and toxicity genes. L. brevis KU202399 exhibited the highest antibacterial activity; L. brevis KU202399 exhibited high cell surface hydrophobicity and decreased adhesion ability of pathogens to intestinal cells. Real-time polymerase-chain reaction results showed significant downregulated expression of antibiotic resistance and toxicity-related gene treatment with L. brevis KU202399. L. brevis KU202399 modulated human fecal microbiota by increasing beneficial bacteria and reducing pathogens. Taken together, our results suggest that L. brevis KU202399 is beneficial in food and probiotic industries.

ABSTRACT The 42 kDa chitinase of T. asperellum SH16 has been regarded with considerable interest in promising biotechnological applications due to its antifungal activities. However, poor thermostability limits most practical applications. This study investigated the expression of various 42 kDa chitinase mutants in E. coli. Findings indicate that the recombinant chitinase I168L mutant demonstrated markedly improved thermostability compared to the native enzyme, retaining substantial activity even at elevated temperatures. Additionally, both in vitro and in vivo antifungal tests showed that the I168L mutant exhibited a greater inhibitory effect on the growth of Colletotrichum siamense strains, which are responsible for anthracnose in chili fruits, when compared to the native chitinase at 35°C. This mutant can prevent fungal infection for up to four days following pretreatment with 80 units of I168L. These findings highlight the potential of the I168L mutant as a biocontrol agent against anthracnose diseases caused by Colletotrichum species in fruits.

ABSTRACT This study aimed to assess the technological, safety, antibiotic resistance, and antifungal properties of 35 lactic acid bacteria (LAB) from Sicilian dairy products. Sixteen Lactiplantibacillus plantarum isolates produced diacetyl, and 30 LAB isolates showed proteolytic activity, suggesting technological potential. All isolates presented weak milk acidification capacity. Aminopeptidase activity varied, with PepX (5/35) and PepN (2/35) showing better activity on Lactiplantibacillus fermentum, Lactobacillus sp. and L. plantarum strains, indicating species-specificity. None of the isolates showed hemolytic, gelatinase, DNase, or coagulase activity. Most were resistant to oxacillin, tetracycline, rifampicin, and vancomycin. Regarding antifungal activity, L. plantarum (n = 10) and Lactiplantibacillus sp. (n = 1) isolates inhibited Aspergillus niger and Penicillium chrysogenum, while L. rhamnosus (n = 5) strains were active against P. chrysogenum. Overall, Lactiplantibacillus isolates, particularly L. plantarum from donkey milk, showed promising technological traits, safety, and potential as bioprotective cultures. These findings support the search for new strains with improved characteristics and technological applications.

ABSTRACT Glycerol has widespread applications in food, pharmaceuticals, cosmetics, and various industrial sectors. While its chemical production entails purification challenges, microbial fermentation, particularly employing Saccharomyces cerevisiae, presents a promising alternative. This study used computational techniques to identify potential inhibitors of S. cerevisiae alcohol dehydrogenase (ADH) to enhance glycerol production. High-throughput virtual screening of 190,000 natural compounds from the ZINC database revealed 116 potential ADH inhibitors. Based on in silico toxicity screening, six compounds, including a quinoline derivative, ZINC000005398892, imidazopyridoindol analog (ZINC000008918046), and four hydroxyoctahydroisoquinolin-chromenone derivatives, ZINC000002111805, ZINC000015954814, ZINC000104739723, and ZINC000002111093, were predicted to be non-mutagenic and non-carcinogenic. Molecular dynamics (MD) simulation studies confirmed the stability of these compounds during 50 ns. ZINC000002111093 was found to be the best compound in this regard. Overall, the selected natural compounds could be potential candidates to direct the metabolic pathway in S. cerevisiae toward enhanced production of glycerol instead of alcohol. Experimental studies can confirm these findings.

ABSTRACT In this study, we evaluated the gastroprotective effects of Lactiplantibacillus plantarum E2_MCCKT (isolated from fermented food) using a cold-restraint stress-induced gastric ulcer mice model. Male mice (28.4 ± 1.62 g) were divided into three groups (n = 10): normal (N), positive control (PC), and treatment with Lp. plantarum E2_MCCKT (T) group. After 30 days of oral supplementation (109 CFU/day), the treatment group had significantly less gastric erosion. The histopathological study clearly showed that probiotic Lp. plantarum E2_MCCKT could protect the stomach epithelial cells from cold injury. The strain also modulated gastric inflammation by upregulating IL-10 (2.31 ± 0.01-fold) and downregulating IFN-γ (2.17 ± 0.03-fold), IFN-λ (10.05 ± 0.03-fold), and IL-12 (1.31 ± 0.03-fold) mRNA expressions in the T group. Additionally, it increased IL-10 (1.06 ± 0.06-fold) and PPAR-α (1.13 ± 0.02-fold) protein expression while reducing IL-6 (1.18 ± 0.07-fold) and PPAR-γ (1.11 ± 0.03-fold), demonstrating its anti-inflammatory properties. Hence, the isolated Lp. plantarum E2_MCCKT might be an alternative therapeutic agent for cold-restraint stress-induced gastric ulcer treatment.

ABSTRACT This study aimed to investigate the effects of a combination of Lactobacillus and inulin (LI) on memory impairment, gut microbiota composition, and metabolic profiles in APP/PS1 transgenic mice (MC). Mice treated with LI exhibited significant improvements in memory performance, along with marked reductions in Aβ plaque deposition, neuroinflammation, and oxidative stress levels. Treatment with LI significantly increased the relative abundances of unclassified_f__Lachnospiraceae, Faecalibaculum, and Blautia, while significantly reducing Candidatus_Saccharimonas. Metabolomics analysis revealed that LI treatment led to elevated levels of acetylcholine, LysoPC (17:0), and sphinganine 1-phosphate, and a significant decrease in phosphocholine level. KEGG pathway analysis indicated that glycerophospholipid and sphingolipid metabolism were likely involved. In particular, Faecalibaculum and Candidatus_Saccharimonas may improve memory by modulating glycerophospholipid and sphingolipid pathways, respectively. These findings offer novel insights into microbiota-targeted strategies for memory enhancement.

ABSTRACT The urgent need for new antimicrobial agents arises from the global challenge of drug resistance due to widespread misuse of antibiotics. Bacteriocins, with unique mechanisms targeting bacterial lipid II, offer a promising solution. Produced mainly by lactic acid bacteria (LAB), bacteriocins exhibit a narrow inhibitory spectrum, potentially reducing development of drug resistance as compared to antibiotics. Advancements in genetics and associated engineering technology have led to the discovery of ribosomal synthesized and post-translationally modified peptides, such as lantibiotics, which are a class of cyclic peptide antibiotics characterized by thioether amino acids, dehydroalanine, 2-aminoisobutyric acid, and unsaturated amino acids. Complex post-translational modifications render lantibiotics effective against foodborne pathogens. The aim of this review is to summarize major lantibiotics produced by LAB, including structural differences, synthesis patterns, and functions of different enzymes involved in biosynthesis. Understanding the structure and biosynthesis mechanisms of lantibiotics is crucial for their applications in food preservation and synthetic biology.

ABSTRACT The enzyme L-asparaginase is used in medicine and food to reduce the risk of cancer by both increasing the breakdown of acrylamide and preventing its formation. In the study, Cleistothelebolus nipigonensis was used as a new source of L-asparaginase. L-asparaginase from this fungus was partially purified and its degradation potential was investigated using pure acrylamide. Potatoes were fried using this method to determine the potential use of L-asparaginase in the food industry. Acrylamide formation and degradation were determined by LC-MS/MS. As a result of the study, it was found that purified L-asparaginase prevented acrylamide formation by 100% and degraded acrylamide by 90% when applied to potatoes. The tests carried out with L-asparaginase isolated from the fungus C. nipigonensis, which was used for the first time in this study as a new source, showed that it can be successfully used to prevent acrylamide formation in food applications.