Improved n -Butanol Production from Clostridium cellulovorans by Integrated Metabolic and Evolutionary Engineering

Abstract

Due to a lack of genetic tools, Clostridium cellulovorans DSM 743B has not been comprehensively explored as a putative strain platform for n -butanol production by consolidated bioprocessing (CBP). Based on the previous study of genetic tools, strain engineering of C. cellulovorans for the development of a CBP-enabling microbial chassis was demonstrated in this study. Metabolic engineering and evolutionary engineering were integrated to improve the n -butanol production of C. cellulovorans from the low-cost renewable agricultural waste of alkali-extracted, deshelled corn cobs (AECC). The n -butanol production from AECC was increased 138-fold, from less than 0.025 g/liter to 3.47 g/liter, which represents the highest titer of n -butanol produced using a single recombinant clostridium strain by CBP reported to date. This engineered strain serves as a promising chassis for n -butanol production from lignocellulose by CBP.