title: Synthesis of FAEEs from glycerol in engineered Saccharomyces cerevisiae using endogenously produced ethanol by heterologous expression of an unspecific bacterial acyltransferase.
abstract: The high price of petroleum-based diesel fuel has led to the development of alternative fuels, such as ethanol. Saccharomyces cerevisiae was metabolically engineered to utilize glycerol as a substrate for ethanol production. For the synthesis of fatty acid ethyl esters (FAEEs) by engineered S. cerevisiae that utilize glycerol as substrate, heterologous expression of an unspecific acyltransferase from Acinetobacter baylyi with glycerol utilizing genes was established. As a result, the engineered YPH499 (pGcyaDak, pGupWs-DgaTCas) strain produced 0.24 g/L FAEEs using endogenous ethanol produced from glycerol. And this study also demonstrated the possibility of increasing FAEE production by enhancing ethanol production by minimizing the synthesis of glycerol. The overall FAEE production in strain YPH499 fps1Δ gpd2Δ (pGcyaDak, pGupWs-DgaTCas) was 2.1-fold more than in YPH499 (pGcyaDak, pGupWs-DgaTCas), with approximately 0.52 g/L FAEEs produced, while nearly 17 g/L of glycerol was consumed. These results clearly indicated that FAEEs were synthesized in engineered S. cerevisiae by esterifying exogenous fatty acids with endogenously produced ethanol from glycerol. This microbial system acts as a platform in applying metabolic engineering that allows the production of FAEEs from cheap and abundant substrates specifically glycerol through the use of endogenous bioethanol.
authors.affiliation: School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Kyung Ok
authors.initials: KO
authors.lastname: Yu
authors.forename: Ju
authors.initials: J
authors.lastname: Jung
authors.forename: Seung Wook
authors.initials: SW
authors.lastname: Kim
authors.forename: Chul Hwan
authors.initials: CH
authors.lastname: Park
authors.forename: Sung Ok
authors.initials: SO
authors.lastname: Han
mesh_terms: D000150:Acinetobacter / Q000201:enzymology* / Q000235:genetics; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D019149:Bioreactors; D000431:Ethanol / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D005285:Fermentation; D005990:Glycerol / Q000378:metabolism*; D060847:Metabolic Engineering; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D005227:Fatty Acids; D011994:Recombinant Proteins; D000431:Ethanol; D000217:Acyltransferases; D005990:Glycerol