An Activity, Stability and Selectivity Comparison of Propioin Synthesis by Thiamine Diphosphate‐Dependent Enzymes in a Solid/Gas Bioreactor
An Activity, Stability and Selectivity Comparison of Propioin Synthesis by Thiamine Diphosphate‐Dependent Enzymes in a Solid/Gas Bioreactor
复制标题
固/气生物反应器中二磷酸硫胺素依赖性酶合成丙酸的活性、稳定性和选择性比较
DOI：
10.1002/cbic.200700095
复制
发表时间：
2007
期刊：
影响因子：
3.2
通讯作者：
J. Büchs
中科院分区：
文献类型：
--
作者：
R. Mikolajek;A. Spiess;M. Pohl;S. Lamare;J. Büchs
固体/气体生物反应器中的酶促碳化反应是生物技术领域的一个新挑战。本文研究了两种丙醛分子在硫胺素依赖的二磷酸酶作用下连续气相合成丙酸的反应。使用两种酶，即荧光假单胞菌的苯甲醛裂解酶(BAL)和恶臭假单胞菌的苯甲酰甲酸脱羧酶(BFD)。这些酶是同源的，催化碳寡酶和碳水解酶反应，不需要外部辅因子再生。考察了水和底物活性对初始反应速率和生物催化剂稳定性的影响。随着水活度的增加，BAL和BFD的初始反应速率分别达到最大值2 5 0和80 U g−1。BAL和BFD的半衰期也呈现相同的趋势，最大值分别为50min和78min。水活度的增加增加了半衰期，这是出乎意料的。还观察到在底物丙醛存在下，BFD比BAL更稳定。在动力学研究中，两种酶都表现出底物抑制，BAL在反应过程中也失活。出乎意料的是，这两种酶的立体选择性(对BAL的ee为19 %，对BFD的外消旋混合物)在气相中比在液体中显著降低。
Enzymatic carboligation in a solid/gas bioreactor represents a new challenge in biotechnology. In this paper, the continuous gas‐phase production of propioin from two propanal molecules by using thiamine diphosphate‐dependent enzymes was studied. Two enzymes were used, namely benzaldehyde lyase (BAL) from Pseudomonas fluorescens and benzoylformate decarboxylase (BFD) from Pseudomonas putida. The enzymes are homologous and catalyze carboligase and carbolyase reactions in which no external cofactor regeneration is needed. The influence of water and substrate activity on the initial reaction rate and biocatalyst stability was investigated. An increase in water activity raised the initial reaction rates to the maximal values of 250 and 80 U g−1 for BAL and BFD, respectively. The half‐life showed the same trend with maximal values of 50 and 78 min for BAL and BFD, respectively. The increase in the half‐life by increasing water activity was unexpected. It was also observed that BFD is more stable than BAL in the presence of the substrate propanal. Both enzymes showed substrate inhibition in the kinetic studies, and BAL was also deactivated during the reaction. Unexpectedly, the stereoselectivity of both enzymes (ee of 19 % for BAL and racemic mixture for BFD) was significantly impaired in the gas phase compared to the liquid phase.
影响因子：
2.9
作者：
Hasson, MS;Muscate, A;Ringe, D
通讯作者：
Ringe, D
啤酒酵母丙酮酸脱羧酶同工酶催化乙偶姻形成。
影响因子：
2.9
作者：
Stivers,JT;Washabaugh,MW
通讯作者：
Washabaugh,MW