Studies on the Breeding of L-Valine Hyper-Producing Mutant

Abstract:

Using Brevibacterium flavum XQ-2(Leul(-ABrAHVr2-TAr) as a starting strain for stepwise mutagenesis by diethylsulfate(DES),N-methyl-N’-nitro-soguanidine(NTG) treatment,a L-valine hyper-producing mutant XQ-8(Leul(-AB hr2-TAhr AHVhr) was obtained,which could be resistant to high concentration α-amino-butyric acid(α-AB),2-thiazole-DL-alanaine(2-TA) and α-amino-β-hydroxy-valeric acid(AHV).As a result,high L-valine concentration(64~66g/L) was obtained with shaking at 31±1℃ for 72h in the medium containing 135g/L glucose and 50g/L(NH4)2SO4.