一株产纤维素酶镰刀菌的筛选、鉴定与酶学性质

Screening and identification of cellulase-producing strain of Fusarium sp. and its enzymological properties

根据菌株菌落、菌丝体、孢子等形态特征及其生理特性,初步鉴定高产纤维素酶的丝状真菌为尖孢镰刀菌(Fusarium oxysporum),命名为XA-1。考察了不同碳源及氮源、培养温度、初始pH等因素对XA-1产酶的影响,并研究了该菌所产纤维素酶酶学性质及酶解性能。该菌的最适产酶条件为:分别以水葫芦和硫酸铵为碳、氮源,30℃,pH 5.0,培养6 d后,内切葡聚糖酶(CMCase)、β-葡萄糖苷酶(β-Gluase)和滤纸酶活力(FPA)分别达到4 083.2、3 258.8 U/g和773.2 U/g(成熟曲)。CMCase、β-Gluase最适反应温度为45℃,FPA则为55℃;CMCase、β-Gluase和FPA的最适反应pH分别为5.0、4.5和5.0。菌株XA-1纤维素酶酶解香蕉秆或水葫芦32 h后,酶解得率分别达到27.3%和29.8%。菌株XA-1在纤维素酶开发及转化秸秆类纤维素为可发酵糖方面显示出较好的应用前景。

A high cellulase-producing filamentous fungi is isolated from the soil of Banana plantations of maoming suburbs. According to its growth characteristics,colony morphology,cell and spore morphology,etc,the strain is preliminary identified as Fusarium oxysporum. The effects of different carbon and nitrogen sources,incubation temperature and initial pH on enzyme production ate investigated. Its cellulase enzymatic properties and enzymolysis properties are also studied. The optimum conditions for enzyme production by strain XA-1 are as follows： 30℃,pH 5. 0,water hyacinth and ammonium sulfate as carbon and nitrogen,respectively. When the strain XA-1 is cultured under the optimum conditions,the maximum activity of CMCase,β-glucosidase and FPA concurrently obtained after 6 days of fermentation are 4 083. 2 IU /g,3 258. 8 IU /g and 773. 2 IU /g,respectively. The optimum reaction temperature for CMCase and β-glucosidase is 45℃ and that of FPA is 55℃. The optimum pH of CMCase,β-Gluase and FPA are 5. 0,4. 5 and 5. 0,respectively. The enzymes activity is stable in the range of pH 4. 0- 6. 0. It indicates that it has good application prospects of strains XA-1 in transforming straw cellulose to fermentable sugars or in the textile.