Genetic systems development in the clostridia

Abstract: This review describes recent developments in the genetic manipulation of the solventogenic clostridia, Clostridium acetobutylicum and C. beijerinckii. It is to be noted that our laboratory stock of C. acetobutylicum ATCC 824, which was obtained from the American Type Culture Collection, has recently been re‐identified as C. beijerinckii NCIMB 8052 based on DNA similarity studies using the S1 nuclease method (personal communication, Dr. Jiann‐Shin Chen, Virginia Polytechnic Institute and State University). Reference to our laboratory 824 culture has been changed to C. beijerinckii NCIMB 8052 throughout this paper in order to be consistent with this finding. The focus of this review specifically involves the characterization of an M13‐like genetic system for the clostridia based on the pCAK1 phagemid, as well as preliminary work on development of a plasmid‐based vector based on the indigenous pDM11 plasmid recovered from C. acetobutylicum NCIB 6443. The construction of a C. beijerinckii strain with amplified endoglucanase activity was achieved by inserting the engB gene from C. cellulovorans into C. beijerinckii. The successful expression of a heterologous engB gene from C. cellulovorans in C. beijerinckii NCIMB 8052 has important industrial significance for the eventual utilization of cellulose by this acetone‐butanol‐ethanol fermentation microorganism.