The Karachi Institute of Biotechnology and Genetic Engineering (KIBGE), University of Karachi, Karachi 75270, Pakistan.
Department of Biochemistry, University of Karachi, Karachi 75270, Pakistan.
Int J Biol Macromol. 2018 Aug;115:776-785. doi: 10.1016/j.ijbiomac.2018.04.089. Epub 2018 Apr 19.
The current study reported the statistically designed experimental method to enhance the biocatalytic efficacy of dextransucrase from Weissella confusa. Various environmental and nutritional parameters were optimized using multiple responses under submerged fermentation environment. Statistical models were constructed to screen the influence of nine factors on the biocatalysis of dextransucrase. Among them, fermentation time, pH, sucrose and peptone exhibited significant probability (P < 0.05) and are considered as substantial constituents in accordance with Plackett-Burman design. Central composite design was further implemented to optimize the levels of selected variables for maximum enzyme yield. The predicted optimum conditions were pH of 7.5 under fermentation time of 8 h with 30.0 g l sucrose and 1.0 g l peptone. The overall enzyme yield increased from 11.4 DSU ml to 52.75 DSU ml with 4.62-fold upsurge after the implementation of the statistical models. Furthermore, SEM analysis showed the biocatalytic conversion of sucrose into highly porous dextran when utilizing dextransucrase. The biopolymer produced under the current optimized model could be utilized as an emulsifying, gelling, stabilizing and thickening agent in food industry.
本研究报道了一种统计学设计的实验方法，旨在提高 Weissella confusa 来源的葡聚糖蔗糖酶的生物催化效率。在浸式发酵环境下，通过多响应优化了各种环境和营养参数。构建了统计模型来筛选 9 个因素对葡聚糖蔗糖酶生物催化的影响。其中，发酵时间、pH 值、蔗糖和蛋白胨具有显著的概率（P < 0.05），并根据 Plackett-Burman 设计被认为是重要的组成部分。进一步实施中心复合设计以优化所选变量的水平，以获得最大酶产量。预测的最佳条件为发酵时间为 8 h、pH 值为 7.5、30.0 g/L 蔗糖和 1.0 g/L 蛋白胨。通过实施统计模型，总酶活从 11.4 DSU/ml 增加到 52.75 DSU/ml，增加了 4.62 倍。此外，SEM 分析表明，利用葡聚糖蔗糖酶将蔗糖生物催化转化为具有高多孔性的葡聚糖。在当前优化的模型下生产的生物聚合物可以用作食品工业中的乳化剂、胶凝剂、稳定剂和增稠剂。
