High production of fatty alcohols in Escherichia coli with fatty acid starvation

Abstract

BackgroundMicrobial biofuel synthesis attracting increasing attention. Great advances have been made in producing fatty alcohols from fatty acyl-CoAs and fatty acids in Escherichia coli. However, the low titers and limited knowledge regarding the basic characteristics of fatty alcohols, such as location and toxicity, have hampered large-scale industrialization. Further research is still needed.ResultsIn this study, we designed a novel and efficient strategy to enhance fatty alcohol production by inducing fatty acid starvation. We report the first use of deletions of acyl-ACP thioesterases to enhance fatty alcohol production. Transcriptional analysis was conducted to investigate the mechanism of the designed strategy. Then, fatty alcohol production was further enhanced by deletion of genes from competing pathways. Fatty alcohols were shown to be extracellular products with low toxicity. The final strain, E. coli MGL2, produced fatty alcohols at the remarkable level of 6.33 g/L under fed-batch fermentation, representing the highest reported titer of fatty alcohols produced by microorganisms.ConclusionsDeletions of genes responsible for synthesis of fatty acids and competing products are promising strategies for fatty alcohol production. Our investigation of the location and toxicity of fatty alcohols suggest bright future for fatty alcohol production in E. coli.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-016-0524-5) contains supplementary material, which is available to authorized users.

Engineering high-level production of fatty alcohols by Saccharomyces cerevisiae from lignocellulosic feedstocks

“…(Clomburg et al, 2015;Goh et al, 2012;Zhou et al, 2016). Among these products, long-chain fatty alcohols in the C12-C18 range have recently received intense attention due to their value and broad applications in laundry detergents, industrial lubricants and surfactants, medicines and personal care products, and potentially as biofuels (Feng et al, 2015;Liu et al, 2016;Pfleger et al, 2015). In 2016, the worldwide market for fatty alcohols was $3.7 billion and growing, with annual production of more than 2.6 metric tons sourced primarily from fossil fuels (petroleum, or polymerized natural gas) or plant oil crops (triglycerides) processed chemically into alcohols (Gaikwad, 2016).…”

Metabolic Engineering for Advanced Biofuels Production and Recent Advances Toward Commercialization

“…Overexpression of an acyl-ACP thioesterase BTE, an acyl-CoA ligase FadD, and an acyl-CoA/aldehyde reductase MAACR to produce 1-dodecanol and 1-tetradecanol intermediates [99] E. coli Fatty alcohols 3.8 g L À1 Batch, 71 h Co-expression of various type I FAS [82] E. coli Fatty alcohols 6.3 g L À1 Fed-batch, 55 h Deletions of acyl-ACP thioesterases to induce fatty acid starvation [81] S. cerevisiae Fatty alcohols 0.1 g L À1 Batch, 96 h Overexpression of fatty acid biosynthesis genes ACC1, FAS1, and FAS2 [77] S. cerevisiae…”

“…[35] A total of 6.3 g L À1 of fatty alcohols were produced in E. coli where acyl-ACP thioesterase (tesA, tesB, and tesC) and the competing pathways for acetyl-CoA supply (ldhA, pta, and ackA) were removed. [81] High fatty alcohol yields (0.13 g fatty alcohol/g glucose) were achieved in E. coli by expression of heterologous FAS I from Corynebacterium glutamicum, which directly releases acyl-CoAs as a final product. [82] This heterologous FAS I could alleviate tight regulation of the native FAS II system in E. coli and decreased the impact of free fatty acid synthesis and CoA reactivation.…”

Metabolic engineering of fatty alcohol production in transgenic hairy roots of Crambe abyssinica

“…The large-scale production of natural fatty alcohols is based on transesterification and hydrogenation of plant oils as well as on hydrolysis or reduction of wax esters. Combining the modern genetic tools and synthetic biology approach allowed for the fatty alcohol production in Escherichia coli (Cao et al, 2015(Cao et al, , 2016Liu et al, 2013Liu et al, , 2016Youngquist et al, 2013;Zheng et al, 2012), yeast (Fillet et al, 2015;Tang and Chen, 2015;Wang et al, 2016), and cyanobacteria (Tan et al, 2011;Yao et al, 2014). Due to a negative environmental impact of the industrial production and diminishing fossil oil reserves, development of a platform for fatty alcohol synthesis from renewable resources is receiving increasing attention.…”