产壳聚糖酶土壤微生物的筛选鉴定及发酵条件优化

Screening and Identification of Chitosanase-producing Microorganisms from Soil and Optimization of the Fermentation Conditions

对浙江舟山虾蟹养殖场附近的土壤进行针对性地采样,通过壳聚糖平板初筛、摇瓶复筛获得一株具有产壳聚糖酶活性的菌株,编号为ZJOU-AC1。通过形态观察、ITS全序列分析及系统发育进化树的构建,确定ZJOU-AC1为鹿皮色曲霉(Aspergillus cervinus)。对其产酶条件进行初步优化,经优化后的培养基成分为胶体壳聚糖1.5%,(NH_4)_2SO_4 0.4%,KH_2PO_4 0.2%,MgSO_4·7H_2O 0.05%。最适发酵周期为96 h。ZJOU-AC1产酶活力由2.05 U/m L提高到4.85 U/m L,与优化前相比提高了2.36倍。

In order to screen desirable strains, we take sample of soil from areas adjacent to manufacturing locations of those plants which culture shrimps and crabs in Zhoushan. In this study,we had isolated a high Chitosanase-producing fungus ZJOU-AC1 from the soil by primary screening of plate specula and shaking cultivation. Based on standard morphological, physiological properties,ITS rDNA sequence and the construction of phylogenetic tree,the fungus ZJOU-AC1 was identified as Aspergillus cervinus. We also optimized the fermentation conditions to increase its productivity of chitosanase. The optimum medium components for chitosanase production by fungus ZJOU-AC1 were determined and listed as follows：colloid chitosan 1.5%,（NH4）2SO40.4%,KH2PO40.2%,MgSO4·7H2O 0.05%. The optimum fermentation period is 96 h. The maximal chitosanase activity could reach 4.85 U/mL when ZJOU-AC1 was incubated in flask under the optimum cultural conditions. The activity increased by 2.36 times in comparison with initial activity of 2.05 U/mL.