Phytase is an additive in animal feed that degrades phytic acid in plant material, reducing feeding costs, and pollution from fecal phosphorus excretion. A multistrategy approach was adopted to improve the expression of E. coli phytase in Pichia pastoris. We determined that the most suitable signal peptide for phytase secretion was an α-factor secretion signal with an initial enzyme activity of 153.51 U/mL. Increasing the copy number of this gene to four increased phytase enzyme activity by 234.35%. PDI overexpression and Pep4 gene knockout increased extracellular phytase production by 35.33% and 26.64%, respectively. By combining favorable factors affecting phytase expression and secretion, the enzyme activity of the phytase-engineered strain was amplified 384.60% compared with that of the original strain. We also evaluated the potential for the industrial production of the engineered strain using a 50-L fed-batch fermenter and achieved a total activity of 30,246 U/mL after 180 h of fermentation.

植酸酶是动物饲料中的一种添加剂，可降解植物材料中的植酸，降低饲料成本以及粪便磷排泄造成的污染。采用多策略方法改善巴斯德毕赤酵母中大肠杆菌植酸酶的表达。我们确定最适合植酸酶分泌的信号肽是α-因子分泌信号，其初始酶活性为153.51 U / mL。将该基因的拷贝数增加至4，可将植酸酶的活性提高234.35％。PDI过表达和Pep4基因敲除分别使细胞外植酸酶产量增加35.33％和26.64％。通过结合影响植酸酶表达和分泌的有利因素，与原始菌株相比，植酸酶工程菌株的酶活性扩增了384.60％。我们还评估了使用50升补料分批发酵罐工业生产工程菌株的潜力，并在发酵180小时后实现了30,246 U / mL的总活性。