Enhanced production of l-lysine by Bacillus megaterium AECR 751 mutant in copra meal through solid-state fermentation

Abstract

This study explored the overproduction of l-lysine in copra meal through solid-state fermentation by regulatory mutants of Bacillus megaterium to improve the l-lysine content of copra meal for animal feed ingredient. Isolation of lysine overproducing mutants of B. megaterium was done by UV-induced and spontaneous mutation using S-(2-Aminoethyl)-l-cysteine. Screening methods showed that classical mutagenesis can harbor mutant strains with improved l-lysine productivity of up to three-fold increase compared to its wildtype strain. Response Surface Methodology was employed to optimize the l-lysine production of the mutant in copra meal wherein glucose supplementation at 30 g/100 g substrate, ammonium sulfate supplementation at 10 g/100 g substrate, 51.68 % moisture content and 2 d fermentation time at 37 °C showed maximum l-lysine yield. This can be used to further investigate the scalability of the process conditions for further development into a potential source of protein feed ingredient in livestock and aquaculture.