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

Abstract

Research background. Lactic acid bacteria (LAB) are known to produce folate. However, this ability is highly strain-dependent. Folate synthesis in specific LAB strains is affected by the availability of folate, which can be consumed by LAB under certain conditions. Moreover, differences in folate synthesis capabilities are related to the presence of folate biosynthesis-related genes and regulation of this pathway. Experimental approach. As basic information to better understand the regulation of folate biosynthesis between LAB species and strains, folate biosynthetic genes were screened and identified in folate-producing and non-folate-producing LAB isolates from various local food sources in Indonesia. The extracellular folate productivity levels of the isolates were analyzed using high-performance liquid chromatography with a diode array detector (HPLC-DAD). Result and conclusions. Eleven of the thirteen LAB isolates tested had all of the eight genes involved in folate biosynthesis (folE, folQ, folB, folK, folP, folC1, folA, and folC2). Furthermore, these isolates produced extracellular folate ranging from 10.37 to 31.10 µg/mL. In contrast, two non-folate-producing isolates lacked several folate biosynthetic genes, such as folQ, folP, and folA, and possibly corresponded to their inability to synthesize folate de novo. Phylogenetic tree construction revealed that the folate biosynthetic genes (excluding folK and folP) from six distinct species of folate-producing LAB isolates were monophyletic with homologous genes from other LAB species in the database. Novelty and scientific contribution. In this study, the distribution of folate biosynthetic genes in various LAB species was determined. The findings from this research support the use of folate biosynthesis marker genes in the genotypic screening for folate-producing LAB.

Potential probiotic characteristics and genomic analysis of a new folate‐producing lactic acid bacteria Lactiplantibacillus plantarum ZFM55

“…Mahara et al tested 13 LAB and found that 11 had eight genes involved in folate biosynthesis (folE, folQ, folB, folK, folP, folC1, folA and folC2) and these isolates had the ability to produce folate. 48 However, the other two isolates that do not produce folate lack genes such as folQ, folP and folA. These results indicated that utilizing genome analysis and KEGG annotation is a fast and effective way to explore the potential folate synthesis ability of microorganisms.…”

Hypothetical Regulation of Folate Biosynthesis and Strategies for Folate Overproduction in Lactic Acid Bacteria

“…Therefore, it has been suggested that folate-producing LAB are unable to reduce oxidized pterin compounds and do not possess a pterin salvage pathway ( de Crécy-Lagard et al, 2007 ; Noiriel et al, 2007 ). Moreover, LAB possessing incomplete genes in the DHPPP (pterin compounds) biosynthetic pathway are unable to synthesize folate ( Mahara et al, 2023 ). This indicates that these LAB cannot produce folate because they cannot produce or salvage pterins.…”