利用具有过水解活性的乙酰基木聚糖酯酶催化制备过氧乙酸

Production of peracetic acid by acetyl xylan esterase with perhydrolysis activity

以甘油三乙酸酯和H2O2为底物,利用来源枯草芽孢杆菌的乙酰木聚糖酯酶(AXE)游离酶和固定化酶催化过水解反应制备过氧乙酸(PAA),并以化学法制备的过氧乙酸为对照组进行性质比较。结果表明:游离酶用量(酶蛋白)为1.0 g/L,可得到11.6 g/L的过氧乙酸,对甘油三乙酸酯的转化率为16.7%;游离酶用量(酶蛋白)为75 mg/L,过氧乙酸质量浓度可达3.5 g/L,对甘油三乙酸酯的转化率为15.3%;固定化酶用量(树脂量)为50 g/L,可得3.6 g/L的过氧乙酸。低浓度过氧乙酸比高浓度过氧乙酸更稳定。将对照组和酶法制备过氧乙酸的质量浓度均设置为3.5 g/L,其pH分别为1.98和4.45;对照组使铜片形成重度腐蚀,对碳钢有轻度腐蚀性,对不锈钢和铝基本无腐蚀;酶法制备的过氧乙酸对上述4种金属均无腐蚀。

Peracetic acid(PAA)was obtained by free and immobilized acetyl xylan esterase(AXE)of Bacillus subtilis,with glyceryl triacetate and hydrogen peroxide as substrate.The results showed that in the presence of 1.0 g/L crude AXE(protein concentration),11.6 g/L PAA could be obtained,the percent conversion of glyceryl triacetate was 16.7%.In the presence of 75 mg/L crude AXE,3.5 g/L PAA could be obtained,the percent conversion of glyceryl triacetate was 15.3%.In the presence of 50 g/L immobilized AXE,3.6 g/L PAA could be obtained.The low concentration products were more stable than the high concentration ones.When chemocatalysis prepared and the enzymatic prepared PAAs were set to concentration as 3.5 g/L,the pH was 1.98 and 4.45,respectively.In the chemocatalysis prepared PAA,severe corrosion and mild corrosion were found on the copper and carbon steel,respectively.The AXE prepared PAA exhibited no corrosion activity toward the two materials.