泡沫分离法回收酶法生产生物柴油中的液体脂肪酶

采用泡沫分离法对酶法生产生物柴油过程中的水相脂肪酶进行回收并富集. 通过正交实验考察了液体脂肪酶溶液中pH值、通气速度、初始酶浓度对富集比、酶蛋白回收率和酶活回收率的影响. 结果表明，气速10 L/(L×h)、进料酶浓度0.2 g/L及pH 7.0时蛋白回收率和酶活回收率接近100%，相应的富集比为3.67；初始酶浓度对富集比和蛋白回收率有显著影响，回收过程中脂肪酶活性无损失. 甲醇的存在能显著提高回收速率，甘油的存在降低了富集比，而生物柴油的存在影响了泡沫的稳定性，要形成稳定的泡沫，生物柴油含量需小于0.01%.

Recovery of Free Lipase in the Aqueous Phase of Enzymatic Production of Biodiesel by Foam Separation

In order to recycle the enzyme for enzymatic production of biodiesel, free lipase in the aqueous phase was recovered and enriched by foam separation. Orthogonal experiments were employed to investigate the effects of air flow rate, initial enzyme concentration and pH value on enrichment ratio, recovery of protein and recovery of enzyme activity. The experimental results showed that the recoveries of protein and enzyme activity reached about 100% with the enrichment ratio of 3.67 when air flow rate, initial enzyme concentration and pH value of feed solution were 10 L/(L×h), 0.2 g/L and 7.0, respectively. Initial enzyme concentration had very significant influence on enrichment ratio. The enzyme activity was well kept during foam separation process. The presence of methanol dramatically increased the foam formation and corresponding enzyme recovery rate; glycerol decreased the enrichment ratio; and biodiesel destroyed the stability of foam. Biodiesel concentration should be lower than 0.01% to obtain stable foam formation.