机构地区: 浙江大学生物系统工程与食品科学学院食品科学与营养系
出 处: 《浙江大学学报(农业与生命科学版)》 2003年第1期59-64,共6页
摘 要: 从肉联厂和屠宰场附近的土壤和污水中采集到的近100个样品中,经富集培养分离到123株能产生弹性蛋白酶的菌株,反复初筛、复筛后,分离到一株产胞外弹性蛋白酶活较高且稳定的细菌,经初步鉴定属芽孢杆菌属(Bacillussp.EL3)。同时研究了其产酶最适条件,产酶最适碳源为葡萄糖,最适氮源为豆饼粉。并对碳源、氮源和生长因子进行了正交实验,研究发现碳源对产酶的影响最大,其次为氮源。当葡萄糖的用量为6%、豆饼粉为5%、玉米提取液为0.2%时,其具有较高的产酶水平。最适发酵初始pH为7.5,250mL最适摇瓶装液量为20mL。在该发酵培养基中培养,35h时达最高的产酶水平。同时还对离心后的粗酶液进行温度和pH试验,发现该酶最适作用温度和pH分别为50℃和7.4,该酶在40℃以下保温30min酶活仍较高,在60℃以上酶活全部丧失。在pH7.4~9.0的范围内比较稳定,而在pH7.0以下时,酶活下降很快。金属离子Cu2+、Zn2+、Al3+能抑制弹性蛋白酶的活性,而Fe3+、Li2+能激活弹性蛋白酶活性,螯合剂EDTA则严重抑制弹性蛋白酶活性。 Strains capable of secreting extracellular elastase were isolated from the soil and wastewater samples that were near the processing factory of pig meat Of them 123 strains produced elastase Strain NoEL3 with the highestyield elastase was identified as Bacillus sp In addition, the experimental results revealed that the most suitable carbon and nitrogen sources for elastase production were glucose 6% and soybean flour 5%, respectively The ANOVA results demonstrated that when glucose was 6%, soybean flour 5% and corn steep flour 02%, it had the highest elastase production When the initial pH of the medium was 75, and 20 mL broth in 250 mL flask it was optimal for elastase production The culture maintained maximum elastase activity at 35 ℃ for 35 hours under the optimized conditions The elastiolytic activity was the highest at pH74 and 50 ℃ This enzyme was stable over the range of pH 7490 and below 40 ℃, and its enzyme activity was inhibited by Cu2+, Zn2+, Al3+ and EDTA Fe3+ and Li2+ were beneficial to enzyme activity