磁性淀粉微球固定化脂肪酶的研究

磁性淀粉微球为载体,采用戊二醛交联法固定化脂肪酶。磁性淀粉微球的主要组成是淀粉和磁粉。结果得到,磁性固定化脂肪酶的总活力、蛋白载量、比活、活性回收率、最适温度和最适pH值分别为4897.15U/g、50.59mg/g、98.58U/mg、72.73%、45℃和8.0。Ca2+、Na+和Mg2+对固定化脂肪酶和自由酶有激活作用,作用大小顺序为Ca2+>Mg2+>Na+。Cu2+和Fe2+对固定化脂肪酶和自由酶有抑制作用,Cu2+的作用尤其明显。脂肪酶被固定化后其热稳定性(在水介质和正己烷中)、操作稳定性、pH稳定性均比自由酶明显提高。固定化脂肪酶和自由酶在4℃下,pH8的PBS和正己烷中保存34d后,其相对活力分别是78.3%和98.8%。

Investigation of Immobilized Lipase onto Magnetic Starchy Microspheres

Lipase has been successfully immobilized by crosslinking with glutaldehyde onto a low-cost magnetic microspheresmade of starch and magnetite powder. The result shows that the mass activity, protein binding, specific activity、 activity retention、optimum temperature and optimum pH of the magnetic immobilized lipase were respectively 4897.15U/g、50.59mg/g、98.58U/mg、72.73%、45℃ and 8. The Ca2+、Na+ and Mg2+ enhanced the activities of immobilized lipase and free lipase,and the action was in the order: Ca2+>Mg2+>Na+. They were inhibited by Cu2+ and Fe2+, particularly by Cu2+. As comparedwith free lipase, the operational , thermal and acid-basc stabilities of immobilized lipase were increased appreciably .After used6 times in the degradation of fat, immobilized lipase retained 67.9 percent of its initial activity. After 34 days at 4℃ in PBS (pH8)and hexane, their remaining activities were respectively 78.3% and 98.8%.