Lindmeyer Martin, Meyer Daniel, Kuhn Daniel, Bühler Bruno, Schmid Andreas
Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Strasse 66, 44227, Dortmund, Germany.
J Ind Microbiol Biotechnol. 2015 Jun;42(6):851-66. doi: 10.1007/s10295-015-1615-8. Epub 2015 Apr 16.
Variability in whole-cell biocatalyst performance represents a critical aspect for stable and productive bioprocessing. In order to investigate whether and how oxygenase-catalyzed reactions are affected by such variability issues in solvent-tolerant Pseudomonas, different inducers, expression systems, and host strains were tested for the reproducibility of xylene and styrene monooxygenase catalyzed hydroxylation and epoxidation reactions, respectively. Significantly higher activity variations were found for biocatalysts based on solvent-tolerant Pseudomonas putida DOT-TIE and S12 compared with solvent-sensitive P. putida KT2440, Escherichia coli JM101, and solvent-tolerant Pseudomonas taiwanensis VLB120. Specific styrene epoxidation rates corresponded to cellular styrene monooxygenase contents. Detected variations in activity strictly depended on the type of regulatory system employed, being high with the alk- and low with the lac-system. These results show that the occurrence of clonal variability in recombinant gene expression in Pseudomonas depends on the combination of regulatory system and host strain, does not correlate with a general phenotype such as solvent tolerance, and must be evaluated case by case.
全细胞生物催化剂性能的变异性是稳定且高效生物加工过程的一个关键方面。为了研究在耐溶剂假单胞菌中，加氧酶催化反应是否以及如何受到此类变异性问题的影响，分别测试了不同的诱导剂、表达系统和宿主菌株，以考察二甲苯单加氧酶和苯乙烯单加氧酶催化的羟基化和环氧化反应的可重复性。与溶剂敏感型恶臭假单胞菌KT2440、大肠杆菌JM101以及耐溶剂台湾假单胞菌VLB120相比，基于耐溶剂恶臭假单胞菌DOT-TIE和S12的生物催化剂的活性变化显著更高。特定的苯乙烯环氧化速率与细胞内苯乙烯单加氧酶含量相对应。检测到的活性变化严格取决于所采用的调控系统类型，alk系统的活性变化高，而lac系统的活性变化低。这些结果表明，假单胞菌重组基因表达中克隆变异性的出现取决于调控系统和宿主菌株的组合，与诸如耐溶剂性等一般表型无关，必须逐案进行评估。
