豆豉中β-甘露聚糖酶高产菌的分离、鉴定及其酶学性质
The Isolation,Identification of β-Mannanase High-Yield Strains from Douchi and β-Mannanase Characterization

通过对传统曲霉型豆豉菌群分离纯化,结合刚果红显色及DNS筛选法,共得到高产β-甘露聚糖酶且形态学差异较大的细菌4株、真菌1株,其中真菌的酶活力为2 016 U?mL-1.经过序列鉴定与比对,细菌鉴定为芽孢杆菌属(Bacillus)不同种,真菌为黑曲霉(Aspergillus niger).酶学性质研究表明:黑曲霉的最适温度和pH值分别为60 ℃和5.0; 4株芽孢杆菌最适作用温度和pH值范围为40～55 ℃和6.0～7.0,其中1株芽孢杆菌在65 ℃时保温240 min或在pH值为9.0时保留30 min,残留相对酶活仍可达61.4%或84.3%.
In this study,by microbial isolation and purification of traditional Aspergillus-type douchi,and following with Congo Red staining and DNS colorimetric methods,a total of four bacterial strains and one fungal strain with high β-mannanase and morphological differences are obtained with a highest enzyme activity of 2 016 U?mL-1 for fungal strain,respectively.Through sequence identification and comparison,bacteria are identified as different species of Bacillus and fungi as Aspergillus niger.The results of enzymatic properties show that the optimum temperature and pH of Aspergillus niger are 60 ℃ and 5.0,respectively.And the optimum temperature range of four Bacillus strains is from 40 ℃ to 55 ℃ and pH range of four Bacillus strains is from 6.0 to 7.0,among which one Bacillus strain keeps at 65 ℃ for 240 min or pH 9.0 for 30 min,and the residual relative enzyme activity is 61.4% or 84.3%