草酸青霉菌生产纤维素酶的反应条件优化

The Optimization of Fermentation Condition for Cellulase Production by Penicillium oxalicum

纤维素酶在生物能源、纺织、饲料和造纸工业等具有重要作用,筛选高效微生物生产菌株,优化最佳产酶工艺,是获得该产品的有效途径。从含有落叶腐木和腐烂秸秆的土壤中筛选出一株高效纤维素降解菌,采用形态学观察及核糖体保守序列分析确定该菌株分类地位,对菌株最适发酵初始p H、最适碳源、氮源及不同表面活性剂选择添加进行最佳产酶条件优化。形态学结合ITS(Internal Transcribesd Spacer)基因序列系统发育学分析确定分离的菌株其为草酸青霉菌,命名为Penicillium oxalicum JG。该菌株以初始p H2.0-3.0,CMC-Na为碳源,豆粉为氮源时,产纤维素酶能力达到最大。不同表面活性剂对菌株产酶影响的结果发现,来源广泛、价格相对较低廉的卵磷脂对草酸青霉菌具有明显的产酶促进作用,发酵液中滤纸酶(FPA)、β-1,4-内切葡聚糖酶(CMCase)和β-葡萄糖苷酶(BGL)活力分别提高72.9%、20.8%和33.6%。草酸青霉菌JG可在酸性初始条件下发酵生产复合纤维素酶,卵磷脂可明显提高其产酶活性。

Cellulase plays an important role in the biological energy, textile, feed, paper industry, et al. Screening efficient strains and optimizing the fermentation condition are the effective way of obtaining cellulase. A cellulose-degrading strain JG was isolated from the soil containing rotten wood and straw. Morphology and molecular phylogenetic studies were used for its identification. Some factors during its fermentation were optimized, including initial p H, carbon source, nitrogen source and surfactants. The strain JG was identified as Penicillium oxalicum by analyzing its morphology and ITS（Internal Transcribesd Spacer）gene sequence phylogenetic systematics. Its optimal cultural conditions for the highest cellulase production were as following ：initial p H values 2-3, carbon and nitrogen source were CMC-Na and soybean meal. Studying the effects of adding different kinds of surfactant on the fermentation process demonstrated that the lecithin of wide source and relatively low price had an obviously high effects on the cellulase production in JG, and the enzyme activities of FPA, CMCase, and BGL increased by 72.9%, 20.8% and 33.6% respectively. In conclusion, JG produced cellulase under lower initial p H, and lecithin enhanced its cellulase activity significantly.