Continuous ethanol production from wheat straw hydrolysate by recombinant ethanologenic Escherichia coli strain FBR5

Abstract

Continuous production of ethanol from alkaline peroxide pretreated and enzymatically saccharified wheat straw hydrolysate by ethanologenic recombinant Escherichia coli strain FBR5 was investigated under various conditions at controlled pH 6.5 and 35 °C. The strain FBR5 was chosen because of its ability to ferment both hexose and pentose sugars under semi-anaerobic conditions without using antibiotics. The average ethanol produced from the available sugars (21.9-47.8 g/L) ranged from 8.8 to 17.3 g/L (0.28-0.45 g/g available sugars, 0.31-0.48 g/g sugar consumed) with ethanol productivity of 0.27-0.78 g l(-1)h(-1) in a set of 14 continuous culture (CC) runs (16-105 days). During these CC runs, no loss of ethanol productivity was observed. This is the first report on the continuous production of ethanol by the recombinant bacterium from a lignocellulosic hydrolysate.