Authors: Liwei Chen Jianhua Zhang Jaslyn Lee Wei Ning Chen
Publish Date: 2014/04/26
Volume: 98, Issue: 15, Pages: 6739-6750
Abstract
Production of biofuels derived from microbial fatty acids has attracted great attention in recent years owing to their potential to replace petroleumderived fuels To be cost competitive with current petroleum fuel flux toward the direct precursor fatty acids needs to be enhanced to approach high yields Herein fatty acylCoA metabolism in Saccharomyces cerevisiae was engineered to accumulate more free fatty acids FFA For this purpose firstly haploid S cerevisiae double deletion strain △faa1△faa4 was constructed in which the genes FAA1 and FAA4 encoding two acylCoA synthetases were deleted Then the truncated version of acylCoA thioesterase ACOT5 Acot5s encoding Mus musculus peroxisomal acylCoA thioesterase 5 was expressed in the cytoplasm of the strain △faa1△faa4 The resulting strain △faa1△faa4 Acot5s accumulated more extracellular FFA with higher unsaturated fatty acid UFA ratio as compared to the wildtype strain and double deletion strain △faa1△faa4 The extracellular total fatty acids TFA in the strain △faa1△faa4 Acot5s increased to 643fold as compared to the wildtype strain during the stationary phase UFA accounted for 42 of TFA in the strain △faa1△faa4 Acot5s while no UFA was detected in the wildtype strain In addition the expression of Acot5s in △faa1△faa4 restored the growth which indicates that FFA may not be the reason for growth inhibition in the strain △faa1△faa4 RTPCR results demonstrated that the derepression of fatty acid synthesis genes led to the increase of extracellular fatty acids The study presented here showed that through control of the acylCoA metabolism by deleting acylCoA synthetase and expressing thioesterase more FFA could be produced in S cerevisiae demonstrating great potential for exploitation in the platform of microbial fatty acidderived biofuels
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