Modification of histidine biosynthesis pathway genes and the impact on production of L-histidine in Corynebacterium glutamicum.
Histidine biosynthesis in Corynebacterium glutamicum is regulated not only by feedback inhibition by the first enzyme in the pathway, but also by repression control of the synthesis of the histidine enzymes. C. glutamicum histidine genes are located and transcribed in two unlinked loci, hisEG and hisDCB-orf1-orf2-hisHA-impA-hisFI. We constructed plasmid pK18hisDPtac to replace the native hisD promoter with the tac promoter, and overexpressed phosphoribosyl-ATP-pyrophosphohydrolase, encoded by hisE, and ATP-phosphoribosyltransferase, encoded by hisG. The L-histidine titer at 0.85 g l(-1) was 80 % greater in the transformed bacterium and production of byproducts, L-alanine and L-tryptophan, was significantly decreased. However, accumulation of glutamic acid increased by 58 % (2.8 g l(-1)). This study represents the first attempt to substitute the histidine biosynthesis pathway promoter in the chromosome with a stronger promoter to increase histidine production.
College of Biotechnology, Tianjin University of Science & Technology, Key Laboratory of Industrial Microbiology of Education Ministry, Tianjin 300457, China.
Yongsong
Y
Cheng
Yunjiao
Y
Zhou
Lei
L
Yang
Chenglin
C
Zhang
Qingyang
Q
Xu
Xixian
X
Xie
Ning
N
Chen
D001276:ATP Phosphoribosyltransferase / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001709:Biotechnology; D048230:Corynebacterium glutamicum / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D005285:Fermentation; D006639:Histidine / Q000096:biosynthesis* / Q000235:genetics; D053858:Metabolic Networks and Pathways; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic
D001426:Bacterial Proteins; D006639:Histidine; D001276:ATP Phosphoribosyltransferase