Mutagenesis induced hyperproduction of L-lysine in shake flask and fermenter by Brevibacterium flavum IIBUV2

Two bacterial cultures of corynebacterium glutamicum and brevibacterium flavum were screened for maximum llysine synthesis in shake flask. among these,the best culture i.e.,b. flavum was subjected to mutagenesis through uv irradiation,ethidium bromide and nitrous acid treatment for enhanced production of l-lysine. among five isolated mutants screened for efficiency towards l-lysine synthesis b. flavum iibuv2 was found to be the best producer. b. flavum iibuv2 and its wild type were,then,compared to find out an appropriate cultivation media and conditions. maximum l-lysine production of 8.8 g/l was obtained when mutant was cultivated on medium containing (%,w/v): glucose 3.0,peptone 0.5,nh4so4 0.1 and k2hpo2 0.005,ph 7.5 at 32°c with 8% inoculum. when the mutant was cultivated in 7.5 l stirred fermenter the lysine yield was increase up to 17.8 g/l after 120h at 300 rpm agitation and 4.0 vvm aeration.