Abstract

As a pleiotropic regulator, Antibiotic resistant protein B (AbrB) was reported to play important roles in various cellular processes inBacilliand someClostridiastrains. InClostridium tyrobutyricum,abrB(CTK_C 00640) was identified to encode AbrB by amino acid sequence alignment and functional domain prediction. The results ofabrBdeletion or overexpression inC. tyrobutyricumshowed that AbrB not only exhibited the reported characteristics such as the negative regulation on sporulation, positive effects on biofilm formation and stress resistance but also exhibited new functions, especially the negative regulation of carbon metabolism. AbrB knockout strain (Ct/ΔabrB) could alleviate glucose-mediated carbon catabolite repression (CCR) and enhance the utilization of xylose compared with the parental strain, resulting in a higher butyrate titer (14.79 g/L vs. 7.91 g/L) and xylose utilization rate (0.19 g/L·h vs. 0.02 g/L·h) from the glucose and xylose mixture. This study confirmed the pleiotropic regulatory function of AbrB inC. tyrobutyricum, suggesting thatCt/ΔabrBwas the potential candidate for butyrate production from abundant, renewable lignocellulosic biomass mainly composed of glucose and xylose.Keywords:Clostridium tyrobutyricum;AbrB;sporulation;biofilm;carbon catabolite repression