复合固定化酸性脲酶酶膜的制备及应用

用复合固定化方法将酸性脲酶固定在壳聚糖-明胶膜上,探讨了固定化的条件和性质、稳定剂对固定化酶膜的作用、固定化酶膜反应器在黄酒中的应用。结果表明:采用质量浓度为1.0%的壳聚糖和0.75%的明胶混合制备含0.579U/cm2酸性脲酶的酶膜,储存半衰期可达81d;在固定化酶膜中加入10%的甘油,在不影响成膜状态和强度的前提下,固定化酶活回收率由66.4%提高到82.25%,储存半衰期可达100d;将16cm2的酶膜采用间歇振荡法分批处理30mL黄酒12h,在尿素去除率仍达50%以上的前提下,可连续处理8批黄酒,较未加稳定剂的提高2个使用批次,酶膜的使用半衰期有明显提高;将约为500cm2的酶膜以卷式膜形式做成酶膜反应器,以0.5mL/min的流速连续处理2L黄酒时,70h后,尿素去除率仍可达50%,且基本未改变黄酒的风味,并最终达到降低氨基甲酸乙酯(EC)的目的。

Preparation and application of composite immobilized acid urease enzyme membrane

The acid urease was fixed on chitosan-gelatin film by multi-technology,then the conditions and nature of immobilization,the stabilizer of membrane,immobilized enzyme membrane reactor were discussed.The results showed that:the film which containing 0.579U/cm2 acid urease was made by 1.0% chitosan and 0.75% gelatin,the thermal stability and pH stability were improved,the half-lives was 81 days.Added 10% glycerin to the immobilized enzyme membrane,in the premise of not affecting the status and strength of the film,the activity recovery rate was increased from 66.4% to 82.25%,the half-lives was reached 100 days.Adding 16cm2 size of the enzyme membrane to 30mL rice wine,12h intermittent oscillation,which can consecutively deal with 8 batches rice wine before the activity reduced by half,improved two batches comparing with adding no stabilizers and the half-lives of enzyme membrane significantly increased.An enzyme membrane reactor was made of 500cm2 membrane in the form of roll film.Rice wine flowed at the rate of 0.5mL/min,continuously dealled with 2L of wine,the urea removal rate was still 50% without changing the wine flavor,and the carcinogenic substances-ethyl carbamate(EC)was reduced.