β-葡萄糖苷酶高产菌株的筛选及其性质研究

从腐败的纤维质中分离筛选得到10株β-葡萄糖苷酶产生菌,与实验室保存的9株菌株一起做产酶发酵,其中B2酶活性最高,为24.4 U·mL﹣1,经菌种鉴定为黑曲霉,其β-葡萄糖苷酶最适合的pH值为4.5,最适温度为65℃,在pH值3.0～10.0较稳定;温度稳定性较好,在65℃保温120 min后仍有61.6%的相对活性;终浓度为5 mmol·L﹣1的Fe2+和Mn2+对酶活性有较强的促进作用.该酶较好的热稳定性和pH值稳定性使其显示出较好的应用潜力.

Screening of high production strain of β-glucosidase and its enzyme characteristics

Ten β-glucosidase producing strains were isolated from the cellulosic samples.The highest production strain B2 was finally obtained by screening these 10 strains along with the other 9 strains identified previously as β-glucosidase producers.The B2,identified as Aspergillus niger,showed the yield of β-glucosidase of 24.4 U·mL﹣1 under certain conditions.The optimal pH-value of β-glucosidase was 4.5 and the optimal temperature was 65 ℃.The enzyme was stable in the wide range of pH-value 3.0~10.0.It could retain 61.6% relative activity after incubating 120 min at 65℃,indicating it had a good temperature tolerance.The enzyme was activated significantly by 5 mmol·L﹣1 Fe2+ and 5 mmol·L﹣1 Mn2+.The good pH-value stability and thermal stability of this β-glucosidase showed its potential applications in industry.