长枝木霉菌株T05发酵液抑菌力参数筛选

Parameter Screening of Antifungal Activity of Fermentation Liquid of Trichoderma longibrachiatum T05

为了得到抑菌活性更高的发酵液,研究了长枝木霉(Trichoderma longibrachiatum)菌株T05发酵液及发酵液乙酸乙酯提取物对灰霉病菌(灰葡萄孢(Botrytis cinerea))和杨树烂皮病菌(污黑腐皮壳(Valsa sordida))的抑菌活性,并以V.sordida作为指示菌对发酵液的培养时间、培养温度、初始pH值、接菌量这4项指标进行了筛选。结果表明:T05发酵液对B.cinerea和V.sordida都有一定的抑制作用,对B.cinerea的最高抑菌率为PDB发酵液过滤除菌后在48 h的55.48%,对V.sordida的最高抑制率为改良马丁培养基发酵液过滤除菌后48 h的48.68%;培养7 d的发酵液乙酸乙酯提取物对2种病原菌的抑菌作用更为显著,在24 h的抑菌率都为100%,在96 h时对2种病原菌的抑菌率分别为84.1%和82.6%,均表现出极强的抑菌活性。筛选后获得最高抑菌率的最佳发酵组合为:培养时间6 d、温度28℃、初始pH=6、500 m L的三角瓶装液量250 m L的条件下接菌量为0.5 m L。在该条件下T05发酵液的乙酸乙酯提取物在96 h对V.sordida的抑菌率从82.9%上升到99.0%。

We studied the antifungal activity of fermentation broth and its ethyl acetate extracts of Trichoderma longibrachiatum strain T05, and screened and optimized four parameters including culture time, culture temperature, the initial pH value, and the initial inoculum volume by using Valsa sordida as an indicator pathogen to get higher antifungal activity of the fer- mentation liquid. The fermentation broth of T05 could inhibit both Botrytis cinerea and V. sordida, the highest inhibition rate to B.cinerea was 55.48% by 48 h after the fermentation broth in PDB was removed bacteria by filter, whereas, the highest inhibition rate to V. sordida was 48.68% by 4g h after the fermentation broth in Martin medium was removed bacte- ria by filter. The ethyl acetate extracts of T05 fermentation broth after culturing for 7 d had a stronger antifungal activity both to B. cinerea and V. sordida, the inhibition rate by 24 h were both 100%, and the highest inhibition rate by 96 h were 84.1% and 82.6%, respectively. After screening the optimal parameter combinations to get the highest inhibition rate were： culturing for 6 days, culture temperature of 28 ℃, the initial pH of 6, and the initial inoculum volume of 0.5 mL in 500 mL conical flask bottled 250 mL medium, and the inhibition rate at 96 h was increased from 82.9% to 99%.