Production of free fatty acids (FFAs) and derivatives from renewable non-food biomass by microbial fermentation is of great interest. Here, we report the development of engineered Rhodococcus opacus strains producing FFAs, fatty acid ethyl esters (FAEEs) and long-chain hydrocarbons (LCHCs). Culture conditions were optimized to produce 82.9 g l−1 of triacylglycerols from glucose, and an engineered strain with acyl-coenzyme A (CoA) synthetases deleted, overexpressing three lipases with lipase-specific foldase produced 50.2 g l−1 of FFAs. Another engineered strain with acyl-CoA dehydrogenases deleted, overexpressing lipases, foldase, acyl-CoA synthetase and heterologous aldehyde/alcohol dehydrogenase and wax ester synthase produced 21.3 g l−1 of FAEEs. A third engineered strain with acyl-CoA dehydrogenases and alkane-1 monooxygenase deleted, overexpressing lipases, foldase, acyl-CoA synthetase and heterologous acyl-CoA reductase, acyl-ACP reductase and aldehyde deformylating oxygenase produced 5.2 g l−1 of LCHCs. Metabolic engineering strategies and engineered strains developed here may help establish oleaginous biorefinery platforms for the sustainable production of chemicals and fuels.
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Data pertaining to this study are contained within the published paper and its Supplementary Information, or are available from the corresponding author upon reasonable request.
S.Y.L. declares competing financial interests, as the strains and processes described in this paper are of commercial interest and are patents filed including, but not limited to, KR101546885B1, US9322004B2, KR101334981B1 and WO2011155799A2 for potential commercialization.
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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This work was supported by the Technology Development Program to Solve Climate Changes on Systems Metabolic Engineering for Biorefineries from the Ministry of Science and ICT through the National Research Foundation (NRF) of Korea (grant nos NRF-2012M1A2A2026556 and NRF-2012M1A2A2026557) to S.Y.L.
Supplementary Tables 1–8, Supplementary Figures 1–23, Supplementary Notes 1 and 2
Supplementary Dataset 1 (Raw data of fed-batch fermentations).
Supplementary Dataset 2 (Metabolic reactions for genome-scale modeling).