Effect of dapA gene deletion on L-threonine production by Escherichia coli

Using Red recombination technique,the dapA gene in Escherichia coli 'K12'was replaced,then a mutant without dapA gene was gained,and it was named as K12△dapA.Thus the K12△dapA and Escherichia coli 'K12'were both fermentated under same condition for 48 h,the L-threonine content in K12△dapA broth was 3.71 g/L,which was 3 times of that in Escherichia coli 'K12'broth.The results indicated that dapA gene deletion improved the accumulation of L-threonine.