卡氏德巴利酵母植酸酶在毕赤酵母中的异源表达及优化

【背景】植酸是一种能螯合金属离子和蛋白质的有机磷类化合物,广泛存在于植物组织中,影响动物对营养元素的吸收。在饲料中加入植酸酶可有效降解植酸。【目的】构建毕赤酵母异源表达卡氏德巴利酵母(Debaryomyces castellii,D. castellii)植酸酶的菌株,促进卡氏德巴利酵母植酸酶的研究及工业应用。【方法】将卡氏德巴利酵母植酸酶基因进行密码子优化后转入毕赤酵母GS115中,通过筛选多拷贝、敲除蛋白酶、过表达分子伴侣及转运蛋白的方法获取优势菌株。【结果】所得重组菌株GS115/DCphy(ΔPep4)(BFR2)的产酶酶活是低拷贝菌株的7倍。【结论】研究结果为卡氏德巴利酵母植酸酶的异源表达及潜在工业应用提供了一定的指导。

Heterologous expression and optimization of Debaryomyces castellii phytase gene in Pichia pastoris

Background] Phytic acid is an organophosphorus compound which are widespread in plant tissues. It can chelate nutrient elements such as metal ions and protein in plant tissues, making them unable to be absorbed and utilized by herbivorous monogastric animals. The phytase can effectively catalyze the hydrolysis of phytic acid. Objective] In order to promote the research and industrial application of Debaryomyces castellii phytase, we constructed a recombinant strain that heterologously expressed Debaryomyces castellii phytase in Pichia pastoris. Methods] The phytase gene from Debaryomyces castellii was optimized and transformed into Pichia pastoris GS115. The high expression strain was obtained by screening copy number, knocking out proteases, and co-expressing molecular chaperones and transporters. Results] The enzyme activity in the fermentation supernatant of the recombinant strain GS115/DCphy(ΔPep4)(BFR2) is 7 times that of the low-copy strain. Conclusion] The results can provide some guidance for the heterologous expression and potential industrial application of Debaryomyces castellii phytase.