Zou Shu-Ping, Gu Kai, Zheng Yu-Guo
Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P.R. China.
Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, P.R. China.
Biotechnol Prog. 2018 May;34(3):784-792. doi: 10.1002/btpr.2617. Epub 2018 Feb 12.
Halohydrin dehalogenase (HHDH)-mediated dehalogenation of 1,3-dichloro-2-propanol (1,3-DCP) is a key step in the chemoenzymatic synthesis of epichlorohydrin (ECH) from glycerol. In this study, a covalent immobilization strategy was employed to enhance the stability of Agrobacterium tumefaciens HHDH using epoxy resin ES-103B as a carrier. Under optimal conditions, the activity recovery of ES-103B-immobilized HHDH (HHDH@ES-103B) was 62.4% and the specific activity was 1604 U/g. The HHDH@ES-103B exhibited excellent thermostability, with a half-life of 68.6 days at 40°C, which is 8.0-times higher than that of the free HHDH. A semicontinuous biotransformation of 1,3-DCP to ECH was performed using HHDH@ES-103B as biocatalyst in a recirculating packed bed reactor (RPBR), resulting in an ECH yield of 94.2%, with an average productivity of 5.2 g/L/h. The RPBR system exhibited a high operational stability and even after 50 cycles of reaction, it retained > 90% of the initial conversion. Furthermore, an integrated bioprocess based on in situ product recovery (ISPR) was developed in RPBR to overcome product inhibition. The integrated bioreactor equipped with an external macroporous adsorption resin HZD-9 column led to another 1.6-fold increase in ECH productivity to 8.46 g/L/h. This improved stability and reusability of HHDH@ES-103B demonstrated its potential for the biotransformation of 1,3-DCP to ECH. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:784-792, 2018.
卤代醇脱卤酶（HHDH）介导的1,3 - 二氯 - 2 - 丙醇（1,3 - DCP）脱卤是甘油化学酶法合成环氧氯丙烷（ECH）的关键步骤。在本研究中，采用共价固定化策略，以环氧树脂ES - 103B为载体提高根癌土壤杆菌HHDH的稳定性。在最佳条件下，ES - 103B固定化HHDH（HHDH@ES - 103B）的活性回收率为62.4%，比活性为1604 U/g。HHDH@ES - 103B表现出优异的热稳定性，在40°C下半衰期为68.6天，比游离HHDH高8.0倍。以HHDH@ES - 103B为生物催化剂，在循环填充床反应器（RPBR）中进行了1,3 - DCP到ECH的半连续生物转化，ECH产率为94.2%，平均生产力为5.2 g/L/h。RPBR系统表现出高操作稳定性，即使经过50个反应循环，仍保持>90%的初始转化率。此外，在RPBR中开发了基于原位产物回收（ISPR）的集成生物过程以克服产物抑制。配备外部大孔吸附树脂HZD - 9柱的集成生物反应器使ECH生产力又提高了1.6倍，达到8.46 g/L/h。HHDH@ES - 103B这种提高的稳定性和可重复使用性证明了其在1,3 - DCP生物转化为ECH方面的潜力。©2018美国化学工程师学会生物技术进展，34:784 - 792，2018。
