桦褶孔菌漆酶固定化及其对染料的降解

采用壳聚糖交联法和海藻酸钠-壳聚糖包埋交联法固定化桦褶孔菌产生的漆酶,探讨最佳固定化条件,固定化漆酶的温度,pH稳定性及操作稳定性,并以两种固定化酶分别对4种染料进行了降解.结果表明:(1)壳聚糖交联法固定化漆酶的最佳条件为:壳聚糖2.5%,戊二醛7%,交联时间2h,固定化时间5h,给酶量1g壳聚糖小球:1mL酶液(1U/mL),固定化效率56%;(2)海藻酸钠-壳聚糖包埋交联法固定化漆酶的最佳条件为:海藻酸钠浓度4%,壳聚糖浓度0.7%,氯化钙浓度5%,戊二醛浓度0.6%,给酶量4mL 4%海藻酸钠:1mL酶液(1U/mL),固定化效率高达86%;(3)固定化的漆酶相比游离漆酶有更好的温度和pH稳定性;(4)比较两种固定化漆酶,海藻酸钠-壳聚糖包埋交联法固定化酶的温度及酸度稳定性要优于壳聚糖固定化酶,但可重复操作性要弱于后者,两者重复使用8次后的剩余酶活比率分别为71%及64%;(5)两种固定化酶对所选的4种不同结构的合成染料均有较好的降解效果,其中壳聚糖固定化酶对茜素红的降解效果及重复使用性极佳,重复降解40mg/L的茜素红10次,降解率仍保持在100%.

Immobilization and dye degradation of laccase from Lenzites betulina

Chitosan cross-linking and sodium alginate-chitosan entrapment cross-linking methods were adopted to immobilize laccase produced by Lenzites betulina, and the immobilization conditions were optimized. The thermal, pH and operation stability of the immobilized laccase were also investigated. The immobilized enzymes were used to degrade four synthetic dyes with different chemical structures. The results showed that the best immobilized conditions of chitosan cross-linking method were as follows: chitosan 2.5%, glutaraldehyde 7%, cross-linking period of 2h, immobilization period of 5h, mixture ratio of enzyme (1U/mL) and chitosan beads (g)=1:1. Under these conditions the immobilization efficiency reached 56%. The best immobilized conditions of alginate-chitosan entrapment cross-linking method were: 4% of sodium alginate concentration, chitosan 0.7%, calcium chloride 5%, glutaraldehyde 0.6%, 1:4 mixing ratio of enzyme (1U/mL) and 4% sodium alginate solution. Under these conditions, the immobilization efficiency reached 86%. The results indicated that the immobilized laccase had higher temperature and pH stability than the free laccase. The stability of enzyme immobilized by alginate-chitosan was higher than that by chitosan, but the reuse operability of the former was not as good as that of the latter. After eight times of repeated use, the remaining enzyme activity of alginate-chitosan and chitosan were 71% and 64%, respectively. Both of the immobilized enzymes were proved to be well capable of degrading four kinds of synthetic dyes. The significant degradation effect was achieved by using chitosan-immobilized enzyme on Alizarin red with 40mg/L concentration. The Alizarin red clearance was kept at 100% during ten times of repeated use in degradation.