Isolation, Biochemical Characterization and Screening of Folate Producing Potential Starter Culture from Pigeon Pea and Brown Rice

Abstract

Folate, an essential B vitamin involved in numerous metabolic pathways, can be produced by lactic acid bacteria (LAB). This study isolated and characterized LAB from traditional fermented legumes and cereals to identify strains suitable as high-folate starter cultures. Methotrexate, a folate analogue, was added to the isolation medium to select folate-producing microbes. The isolates underwent morphological, biochemical, and phenotypic characterization using API 50 CHL, and their folate production was evaluated in folate-free Folic Acid Casei Medium (FACM) and during milk fermentation. The 3-aminophenol spectrophotometric method quantified folate synthesis. Isolates were compared with gene bank strains (Lactobacillus delbrueckii subsp. bulgaricus B59387 and L. plantarum B1848). Seven isolates capable of synthesizing folate were identified as L. plantarum, L. brevis, L. acidophilus, Lactococcus, and Streptococcus species. Four of nine strains grew in FACM, with folate content ranging from 1.90 to 86.2 µg/ml. Selected strains significantly (p<0.05) increased folate concentration in fermented milk to three times initial values. Microorganisms from fermented pigeon pea and rice produced lower folate levels than gene bank strains. These findings demonstrate that LAB isolated from fermented brown rice and pigeon pea can synthesize folate in culture media and fermented milk. Their use could help address folate insufficiency through preventive nutrition strategies or intervention research, enabling food manufacturers to develop fermented products with enhanced folate content for improved consumer health.