Production of long chain alcohols and alkanes upon coexpression of an acyl-ACP reductase and aldehyde-deformylating oxygenase with a bacterial type-I fatty acid synthase in E. coli

Mol Biosyst. 2015 Sep;11(9):2464-72. doi: 10.1039/c5mb00268k. Epub 2015 Jul 2.

Abstract

Microbial long chain alcohols and alkanes are renewable biofuels that could one day replace petroleum-derived fuels. Here we report a novel pathway for high efficiency production of these products in Escherichia coli strain BL21(DE3). We first identified the acyl-ACP reductase/aldehyde deformylase combinations with the highest activity in this strain. Next, we used catalase coexpression to remove toxic byproducts and increase the overall titer. Finally, by introducing the type-I fatty acid synthase from Corynebacterium ammoniagenes, we were able to bypass host regulatory mechanisms of fatty acid synthesis that have thus far hampered efforts to optimize the yield of acyl-ACP-derived products in BL21(DE3). When all these engineering strategies were combined with subsequent optimization of fermentation conditions, we were able to achieve a final titer around 100 mg L(-1) long chain alcohol/alkane products including a 57 mg L(-1) titer of pentadecane, the highest titer reported in E. coli BL21(DE3) to date. The expression of prokaryotic type-I fatty acid synthases offer a unique strategy to produce fatty acid-derived products in E. coli that does not rely exclusively on the endogenous type-II fatty acid synthase system.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alcohols / metabolism*
  • Alkanes / metabolism*
  • Catalase / genetics
  • Catalase / metabolism
  • Enoyl-(Acyl-Carrier Protein) Reductase (NADPH, B-Specific) / genetics*
  • Enoyl-(Acyl-Carrier Protein) Reductase (NADPH, B-Specific) / metabolism
  • Enzyme Activation
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism*
  • Fatty Acid Synthase, Type I / genetics*
  • Fatty Acid Synthase, Type I / metabolism
  • Gene Expression*

Substances

  • Alcohols
  • Alkanes
  • Catalase
  • Enoyl-(Acyl-Carrier Protein) Reductase (NADPH, B-Specific)
  • Fatty Acid Synthase, Type I