Enhanced production of butanol and acetoin by heterologous expression of an acetolactate decarboxylase in Clostridium acetobutylicum

Bioresour Technol. 2016 Sep:216:601-6. doi: 10.1016/j.biortech.2016.05.121. Epub 2016 May 31.

Abstract

Butanol is an important industrial chemical and an attractive transportation fuel. However, the deficiency of reducing equivalents NAD(P)H in butanol fermentation results in a large quantity of oxidation products, which is a major problem limiting the atom economy and economic viability of bio-butanol processes. Here, we integrated the butanol fermentation process with a NADH-generating, acetoin biosynthesis process to improve the butanol production. By overexpressing the α-acetolactate decarboxylase gene alsD from Bacillus subtilis in Clostridium acetobutylicum, acetoin yield was significantly increased at the cost of acetone. After optimization of fermentation conditions, butanol (12.9g/L), acetoin (6.5g/L), and ethanol (1.9g/L) were generated by the recombinant strain, with acetone no more than 1.8g/L. Thus, both mass yield and product value were greatly improved. This study demonstrates that reducing power compensation is effective to improve the atom economy of butanol fermentation, and provides a novel approach to improve the economic viability of bio-butanol production.

Keywords: Acetoin; Acetolactate decarboxylase; Butanol; Clostridium acetobutylicum; Zinc supplementation.

MeSH terms

  • Acetoin / metabolism*
  • Bacillus subtilis / genetics
  • Bacterial Proteins / biosynthesis*
  • Bacterial Proteins / genetics
  • Biofuels
  • Butanols / metabolism*
  • Carboxy-Lyases / biosynthesis*
  • Carboxy-Lyases / genetics
  • Clostridium acetobutylicum / enzymology*
  • Ethanol / metabolism
  • Fermentation
  • Gene Expression
  • Genetic Engineering

Substances

  • Bacterial Proteins
  • Biofuels
  • Butanols
  • Ethanol
  • Acetoin
  • Carboxy-Lyases
  • acetolactate decarboxylase