产高温纤维素酶木霉菌株的筛选、鉴定及酶学性质研究

从稻草堆肥中筛选得到一株产高温纤维素酶的霉菌M1,通过形态学观察和分子生物学鉴定,确定其为木霉属(Trichoderma)。在稻草液体发酵培养基中,木霉M1的CMC酶(carboxymethyl cellulase,CMCase)合成模式为同步合成型。酶学性质研究表明,此CMC酶的最适反应pH为4.4,在pH 4.0～6.0保温4h仍可保持95%以上的酶活力;其最适反应温度为75℃,在50℃下保温4h,可保持87%的酶活力;60℃下保温4h,可保持65%的酶活力,具有较好的热稳定性。

Screening and Classification of a Thermophilic Cellulase-producing Trichoderma sp. Strain and the Study of the Enzyme Properties

A fungal strain,designated as M1,producing thermo-tolerant cellulase was isolated from straw compost and classified as Trichoderma sp.via morphological analysis and its 18S rDNA sequence.The pattern of cellulase synthesis by the strain in submerged fermentation with rice straw as the sole carbon source was investigated as well as the enzyme properties of the carboxymethyl cellulase(CMCase).The maximum CMCase activity was observed at pH 4.4 and the CMCase retained more than 95% activity in the pH range of 4.0~6.0 after incubation at 50℃ for 4h.The optimum temperature for the CMCase activity was 75℃;this CMCase maintained 87% and 65% of the initial activity after incubation for 4h at 50℃ and 60℃,respectively,indicating that the enzyme had good thermostability.