一株产木聚糖酶嗜热真菌樟绒枝霉的鉴定及其产纤维质降解酶系分析

Identification of a Xylanase-producing Thermophilic Fungus, Malbranchea cinnamomea,and Analysis of Its Cellulosic Enzymes

对分离得到的一株产耐热木聚糖酶的真菌CAU521进行鉴定,并对其产纤维质降解酶系进行研究.通过菌落形态、显微镜产孢结构以及18S rDNA序列同源性比对等分析,鉴定该菌为樟绒枝霉(Malbranchea cinnamomea),其最适生长温度为45℃,为一株嗜热真菌.该菌能以农业废弃物玉米芯为碳源液体发酵产耐热木聚糖酶,50℃下培养7 d,木聚糖酶的最高酶活力达到173 U/mL.SDS-PAGE和酶谱分析表明该菌株能同时分泌多种纤维质降解酶:4种木聚糖酶、2种纤维素酶、3种葡聚糖酶和1种甘露聚糖酶.结果表明樟绒枝霉CAU521在降解和利用纤维质材料方面具有潜在的应用价值.

A thermostable xylanase-producing fungus, CAU521, was isolated, and the secreted cellulosic enzymes were analyzed in the present study. The strain was identified as Malbranchea cinnamomea by its morphological features and 18S rDNA sequence. M. cinnamomea CAU521 grew optimally at 45 ℃, suggesting it was a thermophilic fungus. This strain produced a maximal xylanase activity of 173 U/mL after 7 days of cultivation in the medium containing corncob as carbon source at 50 ℃. SDS-PAGE and zymogram analysis revealed that M. cinnamomea CAU521 secreted multiform of cellulosic enzymes, including one mannase, three glucanases, two cellulases and four xylanases in the fermentation culture. Therefore, M. cinnamomea CAU521 exhibited favorable potential for degradation and reusing of fiber materials. Fig 6, Ref24