Milk fermented with Lactococcus lactis KLDS4.0325 alleviates folate status in deficient mice

Role of folic acid in regulating gut microbiota and short-chain fatty acids based on an in vitro fermentation model

Folic acid deficiency is common worldwide and is linked to an imbalance in gut microbiota. However, based on model animals used to study the utilization of folic acid by gut microbes, there are challenges of reproducibility and individual differences. In this study, an in vitro fecal slurry culture model of folic acid deficiency was established to investigate the effects of supplementation with 5-methyltetrahydrofolate (MTHF) and non-reduced folic acid (FA) on the modulation of gut microbiota. 16S rRNA sequencing results revealed that both FA (29.7%) and MTHF (27.9%) supplementation significantly reduced the relative abundance of Bacteroidetes compared with control case (34.3%). MTHF supplementation significantly improved the relative abundance of Firmicutes by 4.49%. Notably, compared with the control case, FA and MTHF supplementation promoted an increase in fecal levels of Lactobacillus, Bifidobacterium, and Pediococcus. Short-chain fatty acid (SCFA) analysis showed that folic acid supplementation decreased acetate levels and increased fermentative production of isobutyric acid. The in vitro fecal slurry culture model developed in this study can be utilized as a model of folic acid deficiency in humans to study the gut microbiota and demonstrate that exogenous folic acid affects the composition of the gut microbiota and the level of SCFAs. KEY POINTS: • Establishment of folic acid deficiency in an in vitro culture model. • Folic acid supplementation regulates intestinal microbes and SCFAs. • Connections between microbes and SCFAs after adding folic acid are built.

Integrating fruit by-products and whey for the design of folate-bioenriched innovative fermented beverages safe for human consumption

Global concerns over folate deficiency, the risks of excessive synthetic folic acid consumption, and food loss implications for environmental sustainability and food security drive needs of innovative approaches that align food by-product valorisation with folate bio-enrichment. This study explored the use of three fruit by-products extracts (grape, passion fruit, and pitaya) and whey to develop a folate bio-enriched fermented whey-based beverage. Three strains (Lacticaseibacillus rhamnosus LGG, Bifidobacterium infantis BB-02, and Streptococcus thermophilus TH-4) were tested for folate production in different fermentation conditions in modified MRS medium and in a whey-based matrix prepared with water extracts of these fruit by-products. B. infantis BB-02 and S. thermophilus TH-4, alone and in co-culture, were the best folate producers. The selection of cultivation conditions, including the presence of different substrates and pH, with grape by-product water extract demonstrating the most substantial effect on folate production among the tested extracts, was crucial for successfully producing a biofortified fermented whey-based beverage (FWBB). The resulting FWBB provided 40.7 μg of folate per 100 mL after 24 h of fermentation at 37 °C, effectively leveraging food by-products. Moreover, the beverage showed no cytotoxicity in mouse fibroblast cells tests. This study highlights the potential for valorising fruit by-products and whey for the design of novel bioenriched foods, promoting health benefits and contributing to reduced environmental impact from improper disposal.

Effect of folA gene in human breast milk-derived Limosilactobacillus reuteri on its folate biosynthesis

Introduction

Folate supplementation is crucial for the human body, and the chemically synthesized folic acid might have undesirable side effects. The use of molecular breeding methods to modify the genes related to the biosynthesis of folate by probiotics to increase folate production is currently a focus of research.

Methods

In this study, the folate-producing strain of Limosilactobacillus reuteri B1-28 was isolated from human breast milk, and the difference between B1-28 and folA gene deletion strain ΔFolA was investigated by phenotyping, in vitro probiotic evaluation, metabolism and transcriptome analysis.

Results

The results showed that the folate producted by the ΔFolA was 2-3 folds that of the B1-28. Scanning electron microscope showed that ΔFolA had rougher surface, and the acid-producing capacity (p = 0.0008) and adhesion properties (p = 0.0096) were significantly enhanced than B1-28. Transcriptomic analysis revealed that differentially expressed genes were mainly involved in three pathways, among which the biosynthesis of ribosome and aminoacyl-tRNA occurred in the key metabolic pathways. Metabolomics analysis showed that folA affected 5 metabolic pathways, involving 89 different metabolites.

Discussion

In conclusion, the editing of a key gene of folA in folate biosynthesis pathway provides a feasible pathway to improve folate biosynthesis in breast milk-derived probiotics.

The regulation function of intestinal microbiota by folate-producing Lactiplantibacillus plantarum LZ227

BACKGROUND

Folic acid is a class of B vitamins that have the function of improving intestinal microbiota.

RESULT

Lactiplantibacillus plantarum LZ227, which is a highly folate-producing strain, was used as the research object, and the folic acid produced by LZ227 was further identified by liquid chromatography-mass spectrometry, and the structural diversity, community composition, abundance difference, and short-chain fatty acids content in fermentation broth were studied by the manure slurry fermentation model. The results showed that the folic acid produced by LZ227 was 5-methyltetrahydrofolate.

CONCLUSION

LZ227 can increase the intestinal microbial diversity in the folate-free state, regulate the intestinal flora, increase the abundance of Firmicutes in the intestinal flora, and inhibit the abundance of Bacteroidetes. LZ227 can inhibit the growth of Alistipes, Parabacteroides, and Bacteroides in the intestine. LZ227 significantly reduced the acetic acid content and significantly increased the butyric acid content in the folate-free case. © 2023 Society of Chemical Industry.

Diversity of the bacteriocins, their classification and potential applications in combat of antibiotic resistant and clinically relevant pathogens

There is almost a century since discovery of penicillin by Alexander Fleming, a century of enthusiasm, abuse, facing development of antibiotic-resistance and clear conclusion that the modern medicine needs a new type of antimicrobials. Bacteriocins produced by Gram-positive and Gram-negative bacteria, Archaea and Eukaryotes were widely explored as potential antimicrobials with several applications in food industry. In last two decades bacteriocins showed their potential as promising alternative therapeutic for the treatment of antibiotic-resistant pathogens. Bacteriocins can be characterised as highly selective antimicrobials and therapeutics with low cytotoxicity. Most probably in order to solve the problems associated with the increasing number of antibiotic-resistant bacteria, the application of natural or bioengineered bacteriocins in addition to synergistically acting preparations of bacteriocins and conventional antibiotics, can be the next step in combat versus drug-resistant pathogens. In this overview we focussed on diversity of specific lactic acid bacteria and their bacteriocins. Moreover, some additional examples of bacteriocins from non-lactic acid, Gram-positive and Gram-negative bacteria, Archaea and eukaryotic organisms are presented and discussed. Therapeutic properties of bacteriocins, their bioengineering and combined applications, together with conventional antibiotics, were evaluated with the scope of application in human and veterinary medicine for combating (multi-)drug-resistant pathogens.

Functional bacterial cultures for dairy applications: towards improving safety, quality, nutritional and health benefit aspects

Traditionally, fermentation was used to preserve the shelf life of food. Currently, in addition to favouring food preservation, well standardized and controlled industrial processes are also aimed at improving the functional characteristics of the final product. In this regard, starter cultures have become an essential cornerstone of food production. The selection of robust microorganisms, well adapted to the food environment, has been followed by the development of microbial consortia that provide some functional characteristics, beyond their acidifying capacity, achieving safer, high‐quality foods with improved nutritional and health‐promoting properties. In addition to starters, adjunct cultures and probiotics, which normally do not have a relevant role in fermentation, are added to the food in order to provide some beneficial characteristics. This review focuses on highlighting the functional characteristics of food starters, as well as adjunct and probiotic cultures (mainly lactic acid bacteria and bifidobacteria), with a specific focus on the synthesis of metabolites for preservation and safety aspects (e.g. bacteriocins), organoleptic properties (e.g. exopolysaccharides), nutritional (e.g. vitamins) and health improvement (e.g. neuroactive molecules). Literature reporting the application of these functional cultures in the manufacture of foods, mainly those related to dairy production, such as cheeses and fermented milks, has also been updated.