title: 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.
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.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. zhao5@illinois.edu.
authors.forename: Dan
authors.initials: D
authors.lastname: Coursolle
authors.forename: Jiazhang
authors.initials: J
authors.lastname: Lian
authors.forename: John
authors.initials: J
authors.lastname: Shanklin
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhao
mesh_terms: D000438:Alcohols / Q000378:metabolism*; D000473:Alkanes / Q000378:metabolism*; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D050745:Enoyl-(Acyl-Carrier Protein) Reductase (NADPH, B-Specific) / Q000235:genetics* / Q000378:metabolism; D004789:Enzyme Activation; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D054890:Fatty Acid Synthase, Type I / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression
chemical_list: D000438:Alcohols; D000473:Alkanes; D002374:Catalase; D050745:Enoyl-(Acyl-Carrier Protein) Reductase (NADPH, B-Specific); D054890:Fatty Acid Synthase, Type I