Effects of Disrupting Acetate Formation Pathways in Corynebacterium acetoacidophilum on Succinate Production Under Oxygen Deprivation

Abstract

In order to reduce acetate production and improve succinate production and explore the main acetate formation pathways of C.acetoacidophilum,gene of pta,ackA,ctfA and aceE,which encoded phosphotransacetylase,acetate kinase,CoA-transfease and pyruvate dehydrogenase complex in C.acetoacidophilum were disrupted respectively by the means of homologous recombination.In C.acetoacidophilum△ldhA△pta-ackA,the titer of acetate,gluocse consumption rate,and both yields of acetate and succinate were found to be similar to that of C.acetoacidophilum AldhA.Furthermore,the titer and yield of acetate decreased by81.4%and 77.2%,respectively,the glucose consumption rate decreased by 28.3%and the yield of succinate increased by 25.3%in C.acetoacidophilum △ldhA△ctfA△pta-ackA.In addition,when gene aceE was deleted,C.acetoacidophilum △ldhA△aceE almost produced no acetate,the glucose consumption rate decrease by 35.6%and the yield of succinate increased by 34.7%.Under oxygen deprivation,almost all acetate formed through acetyl-CoA in C.acetoacidophilum.Gene pta,ackA and ctfA were the main genes of acetate formation pathways from acetyl-CoA.Disrupting gene aceE could cut off acetate synthesis in C.acetoacidophilum,and effectively increase succinate production.