纤维素降解真菌的筛选及其产酶条件

【研究目的】为了获得高效降解纤维素的大型真菌菌株，并研究其产酶能力。【方法】通过子实体组织分离，获得18种野生大型真菌菌株，利用刚果红染色法进行初筛，以测定酶活性进行复筛，综合考虑水解圈、水解圈和菌落直径的比值（HC值）、滤纸酶活力（FPA）、内切葡聚糖酶（CX酶）活力、外切葡聚糖酶（C1酶）活力，对试验真菌降解纤维素能力进行综合评价。【结果】筛选出朱红栓菌、彩绒革盖菌、厚贝隐皮孔菌、金耳等4种具有较强产酶能力的大型真菌，测定了它们在不同的培养时间、酶解pH、酶解温度下的FPA和CX酶活力。试验结果表明，4种真菌经发酵培养7天后FPA达到峰值，其Cx酶活力则在第8天达到最高，在pH4.0~5.2时FPA和Cx酶活力较高，在55℃左右时FPA均呈现峰值，Cx酶活力在30~60℃下均保持较高活力。【结论】大型真菌产生的纤维素酶，其FPA和CX酶活力相关性不大，不同真菌产生的纤维素酶具有不同的特性。野生大型真菌是研究和开发纤维素酶的重要资源。

The Screening of Biodegrading Cellulose Fungi and Its Cellulase-Producing Conditions

【OBJECTIVE】 To obtain strains of macrofungi with high cellulase-producing activity,and explore their cellulase-producing conditions.【METHOD】 Eighteen fungi were isolated from fruit body tissue of different wild fungi,and their cellulase activities were measured by using the Congo red dye for preliminary screening and assaying enzyme activity for second-screening,taking hydrolyzation zone,clearing zone ratios （clearing zone diameter/colony diameter）,filter paper activity （FPA）,endo-1,4- β -glucanase activity （activity of C x -enzyme） and exoglucanase activity （activity of C 1 -enzyme） as evaluating selection criteria.【RESULTS】 Four different strains producing high cellulase activity were obtained,which were Trametes cinnabarina,Corilus versicolor,Cryptoderma fastuosum and Tremella aurantialba respectively.The experimental results showed that the peaks of FPA from four strains were present after 7 days and Cx-enzyme activity reached its maximum after 8 days incubation,FPA and C x -enzyme activity were stable at pH 4.0-5.2,the peak FPA occurred at 55° C,high C x -enzyme activities were maintained within 30-60°C.【CONCLUSION】 FPA and C x -enzyme activity of macrofungi exhibited weak relativity,different macrofungi had different characteristic of cellulase.Wild macrofungi are important resources of cellulase for research and development.