两株纤维素降解真菌的分离鉴定及其产纤维素酶酶学性质的初步研究

Isolation and identification of two fungal strains hydrolyzing cellulose and initial characteristics of its produced cellulases

从纤维素富集的环境中采集82个落叶层下面的土壤和腐朽的树木样品，经过初筛获得大约3500株纤维素降解真菌，二次筛选后得到16株纤维素酶活性较高的真菌。以Avicel为底物，测定16株纤维素降解真菌的粗酶活性，发现真菌菌株S10和X5对Avicel有明显的活性，分别为0．119IU／mL、0．025IU／mL。通过形态学观察和rDNA的ITS（内转录间隔区）序列分析，菌株S10被鉴定为针尾曲霉（Aspergillus aculeatus），菌株X5为草酸青霉（Penicillium oxalicum）。对针尾曲霉S10和草酸青霉X5的粗纤维素酶的酶学性质进行初步研究，发现粗酶活性最高的最适pH值分别为5．0、6．0，最适反应温度分别为50～60℃、45～50℃。

In this experiment, 82 samples of soil below forest floor and putrid wood were collected from cellulose enriched environment. Approximately 3500 fungi strains which could hydrolyze cellulose were isolated. Through the second screening, 16 fungal strains with high cellulose activity were obtained. The Avicel was used as substrate, the crude cellulase activity of 16 fungi strains was characterized and two strains named as S10 and X5 had obvious activities on Avicel, and the activity of them was 0. 119 IU/mL and 0. 025 IU/mL, respectively. These two strains were classified as Aspergillus aculeatus S10 and Penicilliurn oxalicum X5 by morphological observation and rDNA ITS sequence analyses, respectively. The initial characteristics of crude cellulase activity of S10 and X5 were studied, and it found that when the crude cellulose activity was the highest, the optimum pH and re- action temperature were 5.0 and 6.0, 50-60 C and 45-50C, respectively.