摘要
经钴60及原生质体紫外联合诱变后,筛选出一株高产植酸酶的菌株(A-828),酶活力达到66,000U/mL,为出发株的17倍。通过滤膜超滤浓缩和Bio-gel P-150层析纯化,纯化倍数为11.2倍,活力回收率为37.7%。SDS-PAGE分析表明,变异株植酸酶的分子量约为66kDa,酶学实验结果表明:该酶的最适pH有两个,分别为2.5和5.5,但在2.5时所表现的活力是5.5时的5倍,酶的最适温度为55℃。在20-60℃保温20min,活力不改变。2mmol/L的Fe2+、Cu2+、Cr3+抑制了酶的活性,但同样浓度Ca2+、Mn2+、EDTA、DTT对酶的活力影响不显著。
Screening out a novel Aspergillus niger strain （A-828） which expresses high active acid phytase through combination mutation by Co-60 and UV. To research its enzymatic characterization, the acid phytase was purified by the steps of ultrafiltration and Bio-gel-P-150 chromatography. The purification ratio and yield was 11.2 and 29%. Result shows that its molecular weight was estimated to be about 66kDa by SDS-PAGE. The phytase activity of A-828 reached to the 66,000U/mL, 17 fold than origin. Its optimum pH of the enzyme activity was both at 2.5 and 5.5, but the largest activity at 2.5 was 5 fold than that at 5.5. Its optimum temperature was 55℃. The thermal stability of the phytase could be unchanged during 20℃ to 60℃ for 20 min. The phytase activity was strongly inhibited by 2mmol/L Cu^2＋, Fe^2＋ and Cr^2＋, while could not be influence by Ca^2＋, Mn^2＋, EDTA, DTT.
出处
《菌物学报》
CAS
CSCD
北大核心
2009年第3期428-434,共7页
Mycosystema
基金
国家科技攻关计划(No.96-03-02-02)
关键词
纯化
原生质体
PHYB
purification, protoplast, phytase
