Regioselective aromatic hydroxylation of quinaldine by water using quinaldine 4-oxidase in recombinant Pseudomonas putida
Regioselective aromatic hydroxylation of quinaldine by water using quinaldine 4-oxidase in recombinant Pseudomonas putida
复制标题
使用重组恶臭假单胞菌中的奎那定 4-氧化酶对奎那定进行水区域选择性芳香羟基化
DOI：
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发表时间：
2011
影响因子：
3.4
通讯作者：
A. Schmid
中科院分区：
文献类型：
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作者：
F. Ö. Ütkür;Sushil Gaykawad;Sushil Gaykawad;Bruno Bühler;A. Schmid
生物催化碳氢化合物氧化功能化通常是使用活细菌中的加氧酶作为生物催化剂来完成的。这些过程通常受到氧气传质、辅因子再生和/或由于形成活性氧物种而导致的酶不稳定的限制。在这里，我们讨论了一种基于含钼脱氢酶的替代方法，该脱氢酶在底物羟化过程中产生而不是消耗还原当量，并以水为氧供体。含钼脱氢酶在克服加氧酶的局限性方面具有很高的潜力。为了评价基于含钼脱氢酶的生物催化剂的适用性和效率，我们研究了含喹啉脱氢酶(QOX)的假单胞菌及其转化为4-羟基喹那定的情况。宿主菌种和碳源的选择是影响生物催化剂效率的关键因素。恶臭假单胞菌KT2440(PKP1)细胞生长在苯甲酸诱导下，具有最高的QOX活性，可用于工艺开发。为了避开底物和产物的毒性/抑制，选择了两液相法。在没有活性曝气的情况下，以1-十二醇为有机载体溶剂，−1/h−1的生产效率为0.4g/ltot−1/h，从而在6小时内积累了2.1g/ltot QOX 1 4-羟基喹那定。该工艺效率与学术和工业应用的生物催化氧化官能化过程的报道值相当，后者强调了含有QOX的重组细胞在不需要活性曝气的情况下用于杂芳烃碳氧化官能化的潜力和可行性。
Biocatalytic hydrocarbon oxyfunctionalizations are typically accomplished using oxygenases in living bacteria as biocatalysts. These processes are often limited by either oxygen mass transfer, cofactor regeneration, and/or enzyme instabilities due to the formation of reactive oxygen species. Here, we discuss an alternative approach based on molybdenum (Mo)-containing dehydrogenases, which produce, rather than consume, reducing equivalents in the course of substrate hydroxylation and use water as the oxygen donor. Mo-containing dehydrogenases have a high potential for overcoming limitations encountered with oxygenases. In order to evaluate the suitability and efficiency of a Mo-containing dehydrogenase-based biocatalyst, we investigated quinaldine 4-oxidase (Qox)-containing Pseudomonas strains and the conversion of quinaldine to 4-hydroxyquinaldine. Host strain and carbon source selection proved to be crucial factors influencing biocatalyst efficiency. Resting P. putida KT2440 (pKP1) cells, grown on and induced with benzoate, showed the highest Qox activity and were used for process development. To circumvent substrate and product toxicity/inhibition, a two-liquid phase approach was chosen. Without active aeration and with 1-dodecanol as organic carrier solvent a productivity of 0.4 g ltot−1 h−1 was achieved, leading to the accumulation of 2.1 g ltot−1 4-hydroxyquinaldine in 6 h. The process efficiency compares well with values reported for academic and industrially applied biocatalytic oxyfunctionalization processes emphasizing the potential and feasibility of the Qox-containing recombinant cells for heteroaromatic carbon oxyfunctionalizations without the necessity for active aeration.