Willaert Ronnie, De Vuyst Luc
Research Group of Industrial Microbiology, Fermentation Technology and Downstream Processing, Vrije Universiteit Brussel, Belgium.
Appl Microbiol Biotechnol. 2006 Jun;71(2):155-63. doi: 10.1007/s00253-005-0163-y. Epub 2005 Oct 11.
The one-step bioconversion of cis-epoxysuccinate (CES) to L(+)-tartaric acid by dried Rhodococcus rhodochrous cells containing CES hydrolase activity was studied by using a continuous bioconversion process. The influence of the pH and the temperature was assessed. A mathematical model was used to quantify the CES hydrolase activity and stability. The optimal pH, which resulted in a maximal CES hydrolase activity and stability, was pH 8.0. A large increase in stability (half-life time) could be obtained when the temperature was decreased from 37 to 14 degrees C during the continuous bioconversion. A total bioconversion was maintained for more than 100 days. This resulted in a large value for the specific productivity since the effect of the large increase in stability was much more important than the decrease of activity at the lower temperature. This continuous bioconversion process was further optimised by calculating the productivity for several continuously stirred tank reactors in series. The specific productivity could be nearly doubled when the number of reactors in the series was increased from 1 to 4.
采用连续生物转化工艺，研究了含有顺式环氧琥珀酸水解酶活性的干燥红平红球菌细胞将顺式环氧琥珀酸（CES）一步生物转化为L（+）-酒石酸的过程。评估了pH值和温度的影响。使用数学模型对CES水解酶的活性和稳定性进行量化。导致CES水解酶活性和稳定性最大的最佳pH值为8.0。在连续生物转化过程中，当温度从37℃降至14℃时，稳定性（半衰期）大幅提高。总生物转化维持了100多天。由于稳定性大幅提高的影响比低温下活性降低的影响更为重要，因此获得了较高的比生产率。通过计算多个串联连续搅拌釜反应器的生产率，进一步优化了该连续生物转化工艺。当串联反应器的数量从1增加到4时，比生产率几乎翻倍。
