Production of biobutanol from cellulose hydrolysate by the<i>Escherichia coli</i>co-culture system

Abstract

The commercialization of the n-butanol bioprocess is largely dependent on the price of feedstocks. Renewable cellulose appears to be an appealing feedstock. The microbial production of n-butanol still remains challenging because of the limited availability of intracellular NADH. To address this issue, an Escherichia coli strain carrying the clostridial CoA-dependent pathway was supplied with heterologous formate dehydrogenase. With the cellulose hydrolysate of rice straw, this single strain produced cellulosic biobutanol with a production yield at 35% of the theoretical and a productivity of 0.093 g L(-1) h(-1). In an alternative method, the production involved a co-culture system consisting of two separate strains provided with the full CoA-dependent pathway. This system achieved a production yield and productivity reaching 62.8% of the theoretical and 0.163 g L(-1) h(-1), respectively. The result indicates that the E. coli co-culture system is technically promising for the production of cellulosic biobutanol.