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[目的]从土壤中分离筛选魔芋软腐病拮抗放线菌,测定其发酵抑菌活性,并对其活性成分进行初步分离。[方法]采用平板对峙培养法筛选出魔芋软腐病拮抗放线菌。对活性较强的拮抗菌株SJK18作不同碳源、氮源、温度及pH等培养条件的单因素试验,并分别测定其发酵液的抑菌活性。分别用乙醇和乙酸乙酯萃取拮抗菌的发酵液,并测定抑菌活性。[结果]共分离得到112株放线菌,其中11株具有抑菌能力。在以玉米粉为碳源、KNO3为氮源、温度为30℃及pH值为6.0的单因素试验条件下,SJK18发酵液的抑菌活性最强,且活性的pH值适应范围在5.5～10.0。乙醇提取物的抑菌圈直径为17.0mm。乙酸乙酯萃取浓缩液无抑菌活性,而其萃余液抑菌圈直径为20.0mm。[结论]筛选获得1株对魔芋软腐病原菌有较强拮抗作用的放线菌。
[Objective] The research aimed to isolate and screen antagonistic actinomycetes of konjac soft rot from soil and measure the antibacterial activity of konjac. The active constituents were separated preliminarily. [Method] The antagonistic actinomycete of konjac soft rot was screened by plate confrontation culture method. A single factor experiment was conducted on the antagonistic strain SJK18 with different carbon source, nitrogen source, temperature and pH, and the antibacterial activity of the fermented liquid was determined. Respectively with ethanol and ethyl acetate extract of antagonistic bacteria fermentation broth, and determination of antibacterial activity. [Result] A total of 112 actinomycetes were isolated, of which 11 had antibacterial activity. Under the single factor test conditions of corn flour as carbon source, KNO3 as nitrogen source, temperature of 30 ℃ and pH value of 6.0, the antibacterial activity of SJK18 fermentation broth was the strongest, and the activity pH range was 5.5 ~ 10.0 . The diameter of the zone of inhibition of ethanol extract was 17.0 mm. Ethyl acetate extract concentrate antibacterial activity, and its raffinate inhibition zone diameter of 20.0mm. [Conclusion] A strain of actinomycetes with strong antagonism against soft rot of konjac was obtained by screening.