The supplementation of phytase in animal feed can increase the bioavailability of phosphorus and mineral elements in monogastric animals and reduce the phosphorus pollution to environment. Therefore, phytase has an extensive application in the feedstuff industry. In this article, an A. Niger strain producing ex-tracellular phytase was isolated and the phyA gene was cloned. The gene was inserted into prokaryotic expres-sional vector pET21b and pET30a, and then the recombinant plasmids were transformed into Escherichia coli strain BL21 (DE3) by heat shock. A large amount of phytase protein could be obtained via induction of the engineering strains.%在饲料中添加植酸酶可以提高植物性饲料中磷的利用率和单胃动物对矿质元素的吸收,并减轻动物排泄物中磷对环境的污染,具有广泛的应用前景.本试验以自行分离得到的黑曲霉菌株基因组DNA为模板,克隆得到植酸酶phyA基因,并将其连接到原核表达载体pET21b、pET30a上,利用热激转化的方法将重组载体转入大肠杆菌BL21 (DF3)中,构建植酸酶大肠杆菌工程菌株.工程菌株在经诱导后可以产生大量的植酸酶蛋白.
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