2,3-Butanediol production from cellobiose using exogenous beta-glucosidase-expressing Bacillus subtilis

We engineered efficient 2,3-butanediol (23BD) production from cellobiose using Bacillus subtilis. First, we found that B. subtilis harboring an empty vector could produce 23BD from cellobiose. However, productivity using cellobiose as a carbon source was lower than that when using glucose. This lower productivity was improved by adding purified beta-glucosidase from Thermobifida fusca YX (Tfu_0937) in the fermentation. Encouraged by these findings, we found that hydrolysis of cellobiose to glucose was an important reaction of 23BD biosynthesis in B. subtilis using cellobiose. Hence, we created efficient 23BD production from cellobiose using exogenous Tfu_0937-expressing B. subtilis. Using the engineered strain, 21.2 g L−1 of 23BD was produced after 72 h of cultivation. The productivity and yield were 0.294 g L−1 h−1 and 0.35 g 23BD/g cellobiose, respectively. We successfully demonstrated efficient 23BD production from cellobiose by using BGL-expressing B. subtilis.