Glutamicum Aspartokinase Gene Cloning And Applied Research

A combined metabolic mutated strain (YS -C)was get by traditional filter method from Corynebacterium glutamicum(YS).This mutant is threonine auxotrop,AEC and AHV resistant,and it can grow in the medium which contants SCA as the only source of carbon,and the mutant can endure hight leveal of Leu .The mutanted strain can concentrate lysine.The concentration of lysine leveal was 1.20g/l. It was 3.42 times than the former strain YS.Aspartokinase gene (lysC) from AEC resistant mutant Corynebacterium glutamicum GX was cloned and sequened.The lysC gene was recombinanted with the shuttle plasmid vector pEK to form recombinanted plasmid pELY. A recombine Corynebacterium glutamicum strain CZL which contains recombinanted plasmid pELY was transformated by eletric shock. Strain CZL can accumulate 6.94g/l lysine, which was 5.78 times than YS-C and 19.8 times than YS.Shake-flask culture condition of lysine fermentation were studied with CZL .Appropriate feeding of organic niteogen sources was favorable for fermentation jn our experiment, the concentations of the yeast extract and beef extract were 15g/l and 25g/l .The initial (NH02SO4 and glucose concentrations suitable for fermentor production ranged form 55g/l and 150-180g/l respectively. The optimal condition of fermenation was 30' C, 48hours, and the vibration frequency was 115 rpm . 20g/l of Lys concentrtion was obtained under this condition.