Solid-state fermentation production of L-lysine by Corynebacterium glutamicum (ATCC 13032) using agricultural by-products as substrate

To meet the growing demand for L-lysine, an essential amino acid with various applications, it is crucial to produce it on a large scale locally instead of relying solely on imports. This study aimed to evaluate the potential of using Corynebacterium glutamicum ATCC 13032 for L-lysine production from agricultural by-products such as palm kernel cake, soybean cake, groundnut cake, and rice bran. Solid-state fermentation was conducted at room temperature for 72 h, with the addition of elephant grass extract as a supplement. The results revealed that these agricultural by-products contain residual amounts of L-lysine. By employing solid-state fermentation with C. glutamicum (106 CFU/ml) in 100 g of various agricultural by-products, L-lysine production was achieved. Interestingly, the addition of elephant grass extract (1 g of elephant grass: 10 ml of water) further enhanced L-lysine production. Among the tested substrates, 100 g of groundnut cake moistened with 500 ml of elephant grass extract yielded the highest L-lysine concentration of 3.27 ± 0.02 (mg/gds). Furthermore, fermentation led to a substantial rise (p < 0.05) in soluble protein, with solid-state fermented soybean cake moistened with 500 ml of elephant grass extract exhibiting the highest amount of 7.941 ± 0.05 mg/gds. The activities of xylanase, amylase and protease were also significantly enhanced. This study demonstrates a viable biotechnological approach for locally producing L-lysine from agricultural by-products using solid-state fermentation with C. glutamicum. The findings hold potential for both health and industrial applications, providing a sustainable and economically feasible method for L-lysine production.