Folate in Milk Fermented by Lactic Acid Bacteria from Different Food Sources

Abstract

Folates are essential micronutrients, and folate deficiency still occurs in many countries. Lactic acid bacteria (LAB) are known to be able to synthesize folates during fermentation, but the folate production is strain-dependent and influenced by the fermentation medium, presence of a folate precursor, and fermentation time. This study aimed to screen extracellular folate-producing LAB from local food sources and evaluate the factors influencing their folate biosynthesis during milk fermentation. The selection of folate-producing LAB was based on their ability to grow in folate-free medium (FACM), with folate concentrations quantified by microbiological assay. Growth of the 18 LAB in FACM varied between isolates, with only 8 isolates growing well and able to synthesize extracellular folate at relatively high concentrations (up to 24.27 ng/mL). The isolates with highest extracellular folate levels, Lactobacillus fermentum JK13 from kefir granules, Lactobacillus plantarum 4C261 from salted mustard, and Lactobacillus rhamnosus R23 from breast milk, were applied to milk fermentation. The last two isolates were probiotic candidates. The three isolates consumed folate when it was present in the milk, and its consumption was in line with their growth. The availability of folate precursors affected the amount of folate consumed, but did not lead to increased folate concentrations in the medium after 72 h fermentation. The results of this study indicate that these isolates cannot be utilized for producing folate in folate-containing milk, as it shows feedback inhibition on folate biosynthesis.

First report on metagenomics and their predictive functional analysis of fermented bamboo shoot food of Tripura, North East India

“…Pantothenate and biotin metabolic pathway help in the growth of various lactic acid bacteria (Yao et al, 2018). The water-soluble vitamin B group member folate, particularly in the forms of tetrahydrofolate (THF) and methyltetrahydrofolate (MTHF), is crucial for the carbon-1 transfer processes required for the creation of DNA, nucleic acids, amino acids, and other vitamins (Mahara et al, 2021). These metabolic pathways are attributed to microorganisms fermenting the food, lactic acid bacteria have been found to possess the above KEGG 10.3389/fmicb.2023.1158411 metabolic pathways as previously described in the correlation heat map of major lactic acid bacteria species and KEGG pathways (Cui et al, 2023).…”

The Occurrence of Folate Biosynthesis Genes in Lactic Acid Bacteria from Different Sources

“…The inoculum of all LAB isolates was prepared according to a previously described method (18). Bacterial cell pellets grown for 24 h in MRSB were washed twice by centrifugation (Refrigerated Centrifuge LRF-B20, Labtron Equipment Ltd., Camberley, UK) at 10,000 g for 5 min at 4 C and finally resuspended in sterile saline solution (0.85 % w/v NaCl; 106404, Merck KGaA, Darmstadt, Germany).…”

“…The report also suggested that both specific and non-specific detections were thought to indicate the presence of a gene. Two isolates, JK6, and BG8, are known folate non-producers (18) and did not have a complete set of folate biosynthesis genes, possibly leading to their inability to produce folate. The JK6 isolate lacked the folQ gene, while the BG8 isolate lacked folQ, folP, and folA, as indicated by the absence of the corresponding bands upon gel electrophoresis (Figs.…”

“…This might be due to the efficient metabolic regulation in microbes (19), and possibly the presence of feedback-inhibition mechanisms in the regulation of folate biosynthesis (20,21). Consequently, folate in the media may inhibit or inactivate several enzymes involved in folate biosynthesis (18). Folate biosynthesis requires three main building blocks, namely (i) the pteridine moiety (6hydroxymethyl-7,8-dihydropterin pyrophosphate/DHPPP), (ii) PABA (para-aminobenzoic acid), and (iii) glutamate.…”

Role of Vitamin B12 and Folate in Metabolic Syndrome

“…This demonstrated the need for the inclusion of crickets into the human diet, especially in resource-poor populations [32]. In a study directed at isolating strains of lactobacilli synthesizing the highest folate concentration by milk fermentation, it was found that Lactobacillus fermentum (from kefir granules), Lactobacillus plantarum (from salted mustard), and Lactobacillus rhamnosus (from breast milk) produced the highest concentrations of folic acid in the absence of pre-existing folate in milk [33]. An interventional study conducted in India to estimate the potentiality of tea as a scalable vehicle for fortification with vitamins B9 and B12 successfully showed that the daily consumption of a cup of vitamin-fortified tea for two months could benefit women of reproductive age [34].…”