科研之友
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摘要
For whole-cell biotransformations involving toxic organic compounds, two-liquid phase setups are typically applied employing an apolar extractive phase. Bis(2-ethylhexyl)phthalate (BEHP) has proven to be an ideal solvent for stereospecific styrene epoxidation with recombinant E. coli, providing excellent extractive properties and a high biocompatibility. In eco-efficiency evaluations, BEHP, however, has been identified as a critical factor regarding costs and environmental impact. In this study, the constitutive solvent tolerance of Pseudomonas taiwanensis VLB120CttgV is shown to enable high specific activities (up to 180 U g(CDW)(-1)) and extensive reduction of the BEHP amount in two-liquid phase setups and thus to constitute an excellent tool to improve the environmental and economic efficiency of such processes. At a 90% reduction of carrier solvent use and accordingly increased aqueous styrene concentrations, this strain still showed reasonably high specific styrene epoxidation activities (100 U g(CDW)(-1)), while the solvent-adaptable wildtype strain immediately was toxified. A moderate 55% reduction of BEHP enabled a specific activity of 150 U g(CDW)(-1) and thus represents a good trade-off between volumetric productivity maximization and environmental impact minimization. These results for the first time show a clear benefit of a solvent-tolerant compared to solvent-sensitive host strains and how such a benefit can be achieved.
- 出版日期2017-7
- 单位TU Dortmund
