Production of fatty acid-derived oleochemicals and biofuels by synthetic yeast cell factories

Abstract

Sustainable production of oleochemicals requires establishment of cell factory platform strains. The yeast Saccharomyces cerevisiae is an attractive cell factory as new strains can be rapidly implemented into existing infrastructures such as bioethanol production plants. Here we show high-level production of free fatty acids (FFAs) in a yeast cell factory, and the production of alkanes and fatty alcohols from its descendants. The engineered strain produces up to 10.4 g l−1 of FFAs, which is the highest reported titre to date. Furthermore, through screening of specific pathway enzymes, endogenous alcohol dehydrogenases and aldehyde reductases, we reconstruct efficient pathways for conversion of fatty acids to alkanes (0.8 mg l−1) and fatty alcohols (1.5 g l−1), to our knowledge the highest titres reported in S. cerevisiae. This should facilitate the construction of yeast cell factories for production of fatty acids derived products and even aldehyde-derived chemicals of high value.

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

“…A range of enzymes and pathways have been heterologously expressed to convert fatty acid thioesters-produced by endogenous fatty acid biosynthesis-into ethyl esters, acids, alcohols, alkanes, methyl ketones, dicarboxylic acids, etc. (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).…”

Synthetic Biology and Metabolic Engineering Approaches and Its Impact on Non-Conventional Yeast and Biofuel Production

“…Yarrowia lipolytica is a well-studied oleaginous organism and extensively used for industrial biofuel production, and it has been served as a model organism for biofuel research, especially for fatty acid-derived fuels (Beopoulos et al, 2009;Tai and Stephanopoulos, 2013;Blazeck et al, 2014;Zhou et al, 2016). Several metabolic engineering tools are available for Y. lipolytica (Juretzek et al, 2001;Madzak, 2015).…”

Metabolic Engineering for Advanced Biofuels Production and Recent Advances Toward Commercialization

“…[69] S. cerevisiae FAEE, fatty acid short-and branched-chain alkyl esters 230 mg L À1 Batch, 72 h Deletion of Rpd3 and Opi1 with targeted mitochondrial expression of five isobutanol pathway enzymes (Ilv2, Ilv5, Ilv3, Aro10, and Adh7) [75] Y. lipolytica FAEE 142.53 mg L À1 Batch, 90 h ER-targeted expression of Acinetobacter baylyi wax-ester synthase, AbAtfA, and overexpression of a peroxisomal/mitochondrial carnitine acyltransferase, perCat2 [83] Alkanes E. coli Short chain alkanes 0.5 g L À1 Fed-batch a) Deletion of fadR; expression of a modified thioesterase from E. coli [71] E. coli Long chain alkanes 1.3 g L À1 Fed-batch, 40.5 h Modular transcriptional regulation of fatty acid biosynthesis, lipid degradation, and electron transport chain genes. [86] S. cerevisiae Alkanes 0.8 mg L À1 Fed-batch, 72 h Hfd1, pox1, and adh5 deletion with expression of MmCAR [78] Y. lipolytica Alkanes 23 mg L À1 Batch a) Cytosolic expression of Mycobacterium marinum carboxylic acid reductase MmCAR along with an ACP activation module, BsuSfp [95] (Continued)…”

“…[77] A higher titer of fatty acids (1.0 g L À1 ) was reported in plasmid-free S. cerevisiae via accumulating fatty acids and blocking fatty acid activation by deleting two fatty acyl-CoA synthetases (FAA1 and FAA4). [78] Shorter chain fatty acids were also produced in S. cerevisiae by facilitating premature cleavage of shorter fatty acid chains. [79] Pathway optimization and partial disruption of the b-oxidation pathway led to 119 mg L À1 of C 6 -C 10 fatty acids production in S. cerevisiae.…”

“…In S. cerevisiae, 1.5 g L À1 fatty alcohol production was reported by directly converting free fatty acids into fatty aldehydes using a carboxylic acid reductase from Mycobacterium marinum (MmCAR). [78] In addition, the cytoplasmic acetyl-CoA supply was increased by heterologous expression of chimeric citrate lyase pathway enzymes.…”