Improved glycerol utilization by a triacylglycerol-producing Rhodococcus opacus strain for renewable fuels
| Autor: | Anthony J. Sinskey, Andreas Radek, Jens Plassmeier, Kazuhiko Kurosawa |
|---|---|
| Přispěvatelé: | Massachusetts Institute of Technology. Department of Biology, Massachusetts Institute of Technology. Engineering Systems Division, Kurosawa, Kazuhiko, Radek, Andreas, Plassmeier, Jens K., Sinskey, Anthony J. |
| Rok vydání: | 2015 |
| Předmět: |
Co-fermentation
Adaptive evolution Management Monitoring Policy and Law Xylose Biology Triacylglycerol Applied Microbiology and Biotechnology Renewable fuels Glycerol utilization chemistry.chemical_compound Rhodococcus opacus ddc:570 Glycerol Food science Bioprocess Sugar Strain (chemistry) Renewable Energy Sustainability and the Environment General Energy chemistry Biochemistry Fermentation Research Article Biotechnology |
| Zdroj: | Biotechnology for Biofuels Biotechnology for biofuels 8(1), 31-(2015). doi:10.1186/s13068-015-0209-z |
| ISSN: | 1754-6834 |
| DOI: | 10.1186/s13068-015-0209-z |
| Popis: | Background: Glycerol generated during renewable fuel production processes is potentially an attractive substrate for the production of value-added materials by fermentation. An engineered strain MITXM-61 of the oleaginous bacterium Rhodococcus opacus produces large amounts of intracellular triacylglycerols (TAGs) for lipid-based biofuels on high concentrations of glucose and xylose. However, on glycerol medium, MITXM-61 does not produce TAGs and grows poorly. The aim of the present work was to construct a TAG-producing R. opacus strain capable of high-cell-density cultivation at high glycerol concentrations. Results: An adaptive evolution strategy was applied to improve the conversion of glycerol to TAGs in R. opacus MITXM-61. An evolved strain, MITGM-173, grown on a defined medium with 16 g L[superscript −1] glycerol, produced 2.3 g L[superscript −1] of TAGs, corresponding to 40.4% of the cell dry weight (CDW) and 0.144 g g[superscript −1] of TAG yield per glycerol consumed. MITGM-173 was able to grow on high concentrations (greater than 150 g L[superscript −1]) of glycerol. Cultivated in a medium containing an initial concentration of 20 g L[superscript −1] glycerol, 40 g L[superscript −1] glucose, and 40 g L[superscript −1] xylose, MITGM-173 was capable of simultaneously consuming the mixed substrates and yielding 13.6 g L[superscript −1] of TAGs, representing 51.2% of the CDM. In addition, when 20 g L[superscript −1] glycerol was pulse-loaded into the culture with 40 g L[superscript −1] glucose and 40 g L[superscript −1] xylose at the stationary growth phase, MITGM-173 produced 14.3 g L[superscript −1] of TAGs corresponding to 51.1% of the CDW although residual glycerol in the culture was observed. The addition of 20 g L[superscript −1] glycerol in the glucose/xylose mix resulted in a TAG yield per glycerol consumed of 0.170 g g[superscript −1] on the initial addition and 0.279 g g[superscript −1] on the pulse addition of glycerol. Conclusion: We have generated a TAG-producing R. opacus MITGM-173 strain that shows significantly improved glycerol utilization in comparison to the parental strain. The present study demonstrates that the evolved R. opacus strain shows significant promise for developing a cost-effective bioprocess to generate advanced renewable fuels from mixed sugar feedstocks supplemented with glycerol. Sweetwater Energy, Inc. MIT Energy Initiative |
| Databáze: | OpenAIRE |
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