Trivedi Archana H, Spiess Antje C, Daussmann Thomas, Büchs Jochen
Biochemical Engineering, RWTH Aachen University, Worringerweg 1, D-52056 Aachen, Germany.
Biotechnol Prog. 2006 Mar-Apr;22(2):454-8. doi: 10.1021/bp050316g.
The initial reaction rate and the thermostability of the mesophilic alcohol dehydrogenase (ADH) from Lactobacillus brevis (LBADH), and the thermophilic ADH from Thermoanaerobacter sp. (ADH T) in gas-phase reaction were compared. The effects of water activity, cofactor-to-protein molar ratio, and reaction temperature on the reduction of acetophenone to 1-phenylethanol were studied. An optimal water activity of 0.55 in terms of productivity was found for both ADHs. The cofactor-to-protein molar ratio was chosen slightly higher than equimolar to increase both activity and thermostability. An excellent optimal productivity of 1,000 g x L(-1) x d(-1) for LBADH and 600 g x L(-1) x d(-1)for ADH T was found at 60 degrees C, while the highest total turnover numbers with respect to the enzyme were achieved at 30 degrees C and amounted to 4.2 million for LBADH and 1.7 million for ADH T, respectively. Interestingly, the ADH from the mesophilic L. brevisshowed the higher thermostability in the nonconventional medium gas phase.
比较了来自短乳杆菌的嗜温醇脱氢酶（LBADH）和气相反应该嗜热厌氧菌的嗜热醇脱氢酶（ADH T）的初始反应速率和热稳定性。研究了水分活度、辅因子与蛋白质的摩尔比以及反应温度对苯乙酮还原为1-苯乙醇的影响。发现两种醇脱氢酶在生产率方面的最佳水分活度均为0.55。选择略高于等摩尔的辅因子与蛋白质的摩尔比以提高活性和热稳定性。在60℃时，LBADH的最佳生产率为1000 g·L⁻¹·d⁻¹，ADH T为600 g·L⁻¹·d⁻¹，而相对于酶的最高总周转数在30℃时达到，LBADH为420万，ADH T为170万。有趣的是，嗜温短乳杆菌的醇脱氢酶在非传统的气相介质中表现出更高的热稳定性。
