Bi Ke, Zhang Wen, Xiao Zhizhuang, Zhang Dawei
Shandong Provincial Key Laboratory of Microbial Engineering, College of Biotechnology, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China.
Qingdao Red Cherry Biotech Ltd, Qingdao, 266111, China.
AMB Express. 2018 Dec 20;8(1):194. doi: 10.1186/s13568-018-0723-z.
A gene named zenc, encoding a zearalenone lactonase from Neurospora crassa, was over-expressed in Pichia pastoris. The zenc gene is 888-bp in length, encoding a 295-residue polypeptide. Purified ZENC has maximal activity at pH 8.0 and 45 °C, and is highly stable at pH 6.0-8.0 for 1 h at 37 °C. The activity of the secreted enzyme in shaken-flask fermentation was 40.0 U/ml. A high-density fermentation of the ZENC-producing recombinant strain was performed in a 30-l fermenter and the maximal enzyme activity reached 290.6 U/ml. The K, V and specific activity toward zearalenone are 38.63 μM, 23.8 μM/s/mg and 530.4 U/mg, respectively. ZENC can resist metal ions and inhibitors to some extent. We applied the enzyme into three different kinds of animal feed. On addition of ZENC (800 U) to distillers dried grains with solubles (DDGS), maize by-products and corn bran (25 g), the concentration of zearalenone was reduced by 70.9%, 88.9% and 94.7% respectively. All these properties of ZENC are promising for applications in the animal feed and food industries.
一个名为zenc的基因，编码来自粗糙脉孢菌的玉米赤霉烯酮内酯酶，在毕赤酵母中过表达。zenc基因长度为888个碱基对，编码一个295个氨基酸残基的多肽。纯化后的ZENC在pH 8.0和45℃时具有最大活性，在37℃下于pH 6.0 - 8.0范围内1小时内高度稳定。摇瓶发酵中分泌酶的活性为40.0 U/ml。在30升发酵罐中对产ZENC的重组菌株进行高密度发酵，最大酶活性达到290.6 U/ml。其对玉米赤霉烯酮的Km、Vmax和比活性分别为38.63 μM、23.8 μM/s/mg和530.4 U/mg。ZENC在一定程度上可以抵抗金属离子和抑制剂。我们将该酶应用于三种不同的动物饲料中。在向含有可溶物的干酒糟（DDGS）、玉米副产品和玉米麸皮（25克）中添加ZENC（800 U）后，玉米赤霉烯酮的浓度分别降低了70.9%、88.9%和94.7%。ZENC的所有这些特性在动物饲料和食品工业中的应用前景广阔。
