基于生物催化法的食品熏蒸剂环氧乙烷制备

Producing Epoxyethane as Food Fumigant Based on Biocatalysis

为了探索一种反应条件温和、方法简单的食品熏蒸剂环氧乙烷制备方法,采用甲基弯菌IMV 3011(Methylosinus trichosporium IMV 3011)细胞作为生物催化剂,催化乙烯的环氧化反应生成环氧乙烷,确定了反应条件。结果表明:反应器中气相的组成为氧气50%、乙烯20%、氮气30%(体积分数),30℃、150 r/min振荡反应8 h,采用固定化形式催化剂,环氧乙烷生成量为34μmol/mg,利用甲烷培养对其循环再生,再生8次催化剂中甲烷单加氧酶(MMO)活力仍保留89%,环氧乙烷物质的量为3.4 nmol。

In addition to application in chemical manufacturing processes,epoxyethane is widely used in processes of food fumigating sterilization,particularly of grains and dried fruits. During the last decades,many research works have been focused on epoxidation reactions of ethylene by supported catalysts such as transition metal complexes and metal nanoparticles. In contrast with chemical synthetic methods,the biocatalytic reaction appears to be a mild and simple method. One biocatalytic method for producing epoxyethane is using methane monooxygenase（ MMO） to insert oxygen across the carbon double bonds of ethylene. Epoxyethane synthesis by Methylosinus trichosporium IMV 3011 whole cells which contains the MMO has significant application potential as it is performed at normal temperature and pressure and causes no pollution. The process for producing epoxyethane was described. The effect of initial ethylene concentration on production of epoxyethane was studied. Initial concentrations of oxygen,ethylene and nitrogen were 50%,20% and 30%,respectively. The amount of epoxyethane formed by free biocatalyst was 29 μmol / mg in approximately 6 h. Moreover,the amount of epoxyethane formed by immobilized biocatalyst was 34 μmol / mg in approximately 8 h. In a batch reaction system, the regenerated immobilized biocatalyst can be repeatedly used for 8 times and 89% of initial MMO activity was retained,and the amount of epoxyethane formed was 3. 4 nmol.