Butanol production from cellulosic material by anaerobic co-culture of white-rot fungus Phlebia and bacterium Clostridium in consolidated bioprocessing

Abstract

Butanol production from lignocelluloses is desirable. Unfortunately, the known wild-types of butanol fermenting Clostridium bacteria are not capable of delignification and saccharification. Here we analyzed butanol production from cellulosic material using anaerobic co-culture of C. saccharoperbutylacetonicum with the white-rot fungus Phlebia sp. MG-60-P2. In consolidated bioprocessing, the co-culture synergistically produced butanol and enhanced saccharification. Knockout of the pyruvate decarboxylase gene from MG-60-P2 to produce transformant line KO77 led to inhibition of ethanol fermentation and high accumulation of saccharified cellobiose and glucose from cellulose. In co-culture of KO77 with C. saccharoperbutylacetonicum, enhanced butanol production was observed (3.2 g/L, compared with 2.5 g/L in co-culture of MG-60-P2 and C. saccharoperbutylacetonicum). We believe this is the first application of co-culture between white-rot fungus and Clostridium to produce butanol from cellulose; butanol production from lignocellulose by co-culture of C. saccharoperbutylacetonicum with Phlebia sp. MG-60-P2 and its transformant should be pursued.