Abstract:

The present study aimed to expand the utilization of L-lysine-producing strains in food and animal feeds and raise the security of L-lysine production by microbial fermentation. In total, 66 strains having the ability to produce L-lysine were isolated from commercially available doughs for the making of bread, fried dough twists, steamed bread, steamed cake and Russian style bread and kojis for the making of rice wine and distilled liquor. These strains were cultured, and the quantitation of L-lysine content in medium at the end of culture was carried out using HPLC. Two of the 66 isolated strains were found to produce higher amount of L-lysine and the contents of L-lysine in the resultant fermentation broths were 52.33 g/L and 46.09 g/L respectively. Using 16S rDNA sequence and Blast analyses and specific primer PCR technique, they were identified as Leuconostoc mesenteroides ATCC 8293 and Lactobacillus delbrueckii subsp. bulgaricus ATCC BAA-365.

Key words: fermented cereals, L-lysine, probiotics, high-performance liquid chromatography, 16S rDNA, specific PCR