产壳聚糖酶土壤微生物的筛选鉴定及发酵条件优化.doc

产壳聚糖酶土壤微生物的挑选鉴定及发酵条件优化【摘要】：p 】：对浙江舟山虾蟹养殖场附近的土壤进展针对性地采样，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p 及系统发育进化树的构建，确定ZJOU-AC1为鹿皮色曲霉Aspergillus cervinus。对其产酶条件进展初步优化，经优化后的培养基成分为胶体壳聚糖1.5%，NH42SO4 0.4%，KH2PO4 0.2%，MgSO4·7H2O 0.05%。最适发酵周期为96 h。ZJOU-AC1产酶活力由2.05 U/mL进步到4.85 U/mL，与优化前相比进步了2.36倍。【关键词】：p 】：壳聚糖酶，土壤，菌株挑选，菌株鉴定，发酵条件，优化中图分类号：TQ925 文献标识码：A 文章编号：0439-811420_10-1913-05DOI：10.14088/jki.issn0439-8114.20_.10.029Screening and Identification of Chitosanase-producing Microorganisms from Soil and Optimization of the Fermentation ConditionsMAO Gui-zhua，ZHANG Ye-mina，SHAO Yi-fana，_IONG Yan-yana，CHEN _iao-ea，FANG _u-boa，ba.College of Food and Medicine；b.State Key Laboratory of Aquatic Products Processing of Zhejiang Province，Zhejiang Ocean University，Zhoushan 316022，Zhejiang， ChinaAbstract： In order to screen desirable strains， we take sle 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 andshaking cultivation.Based on standard morphological，physiological properties，ITS rDNA sequence and the construction of phylogeic 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 ponents for chitosanase production by fungus ZJOU-AC1 were determined and listed as follows：colloid chitosan 1.5%，NH42SO4 0.4%，KH2PO4 0.2%，MgSO4·7H2O 0.05%.The optimum fermentation period is 96 h.The ma_imal 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 parison with initial activity of 2.05 U/mL.Key words：chitosanase；soil；strain screening；strain identification；fermentation condition；optimization壳聚糖是甲壳素脱N-乙酰基的产物，在自然界中储量丰富，具有平安、无毒、抑菌、成膜、可降解、可食用等多种特性1，但其分子量大，晶体构造严密，水溶性差，在开发应用上存在一定局限性2。根据已有文献报道，通过降解壳聚糖可得聚合度在20以下的壳寡糖，其水溶性好且易被吸收。由于具备独特的功能性质，壳寡糖在废水处理、食品工业、日用化学品、纺织、化工、农业、生物工程和医药等方面均具有广泛的应用前景3-5。壳聚糖的水解方式一般有化学法、物理法和生物酶法，其中，生物酶法是利用非专一或专一性酶对壳聚糖进展降解产生壳寡糖的方法，具有反响过程容易控制、专一性高和反响条件温和等优点。虽然已报道有30多种非专一性酶能降解壳聚糖6，但这些商品酶制剂的水解效率并不高，也尚未被证实是否含壳聚糖酶EC3.2.1.132。壳聚糖酶是一种专一性水解酶，是酶法降解壳聚糖研究的重要内容7。同时，从自然环境中寻找到产壳聚糖酶的新菌株也是壳聚糖应用研究的关键内容8。本研究目的是首先从浙江省舟山市毗邻的常年养殖虾蟹的养殖场附近的山坡及海域挑选壳聚糖酶产生菌株，在此根底上，通过复筛确定产酶才能较强的菌株，并进一步通过发酵条件优化进步其产酶才能，以期获得较好的壳聚糖酶产生菌株，为酶法降解壳聚糖的研究提供高产菌株。第 4 页 共 4 页