| 摘要: |
| 【目的】筛选钩丝孢属真菌高产蛋白酶菌株，并优化其产酶培养基和发酵条件，为寄生线虫病的生物防治提供优良菌种。【方法】以15株钩丝孢属真菌为材料，在28 ℃、180 r/min振荡培养10 d后，采用福林酚法测定其蛋白酶活性，筛选高产蛋白酶菌株，测定其产酶周期，并利用全齿复活线虫测定该菌株发酵液的杀线虫率。通过单因素试验和正交试验对高产蛋白酶菌株的产酶培养基及发酵条件进行优化，并对优化条件进行验证。【结果】从15株钩丝孢属真菌中筛选出1株高产蛋白酶菌株H6，其蛋白酶活性在发酵5 d最高。最佳产酶培养基成分为葡萄糖8 g/L、明胶8 g/L、蛋白胨8 g/L、酵母提取物4 g/L。最佳发酵条件为pH 7.0、20 ℃、260 r/min、接种2块直径5 mm的菌块。在此优化条件下，菌株H6蛋白酶活性为216.42 U/mL，比优化前（67.84 U/mL）提高了2.19倍。【结论】筛选出1株钩丝孢属高产蛋白酶菌株H6，获得了其优化产酶培养基和发酵条件。 |
| 关键词: 钩丝孢属真菌 蛋白酶 寄生线虫 生物防治 |
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| 基金项目:国家自然科学基金项目（31500014）；湖南省教育厅科学研究课题（15C1218）；衡阳市科技计划课题（2016KS26） |
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| Screening of a Harposporium strain with high infectious protease activity and optimization of its fermentation conditions |
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LIU Ziqing,WAN Yile,QUAN Shufen,et al
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| Abstract: |
| 【Objective】This study screened Harposporium strains with high protease activity and optimized the enzyme producing medium and fermentation conditions to provide basis for biological control of parasitic nematode.【Method】A total of 15 Harposporium strains were cultured for 10 days at 28 ℃ and 180 r/min oscillation.The protease activity was determined by Pollin phenol method.The strain with high protease activity was screened and the protease production cycle was confirmed.The nematocidal rate of its fermentation broth was tested by Panagrellus redivivus.The enzyme producing medium and fermentation conditions were optimized by single factor test and orthogonal test.At last,the optimized conditions were verified.【Result】The strain H6 was screened from the 15 Harposporium with the highest protease activity on the 5 th day of fermentation.The optimum medium composition was 8 g/L glucose,8 g/L gelatin,8 g/L peptone and 4 g/L yeast extract and the optimum culture conditions were inoculation volume 2 fungus pieces with 5 mm diameter, temperature 20 ℃,pH 7.0 and rotational speed 260 r/min.Under the optimal fermentation conditions,the protease activity was 216.42 U/mL,which was 2.19 times as that (67.84 U/mL) before optimization.【Conclusion】A strain with high protease activity Harposporium named H6 was screened and its enzyme producing medium and fermentation conditions were optimized. |
| Key words: Harposporium protease parasitic nematode biological control |
