一株链霉菌发酵液的抗菌谱及稳定性

从土壤中分离得到一株放线菌菌株，杯碟法测定该菌株发酵液对14种植物病原真菌和两种植物病原细菌均有不同程度的抑菌活性，其中对烟草黑胫病菌和黄瓜菌核病菌的抑菌效果最好，抑菌圈直径达56．36mm和56．26mm。枯斑抑制法测定发酵液对TMV的抑制作用表明，发酵液对TMV有很好的钝化作用，发酵液与病毒汁液混合10min后接种，枯斑抑制率为93．88％，接种前24h处理和接种后24h处理的枯斑抑制率分别为87．93％和42．21％。通过对发酵液稳定性的初步研究，表明发酵液中的抗菌物质对温度、光照以及pH值变化都比较稳定。

Antimicrobial spectrum and stability of the fermentation broth of Streptomyces

Actinomycete mycelia were isolated from soil and a cylinder-plate assay was used to determine that fermentation broth from these fungal mycelia had varying degrees of inhibitory activity towards 14 plant pathogenic fungal species and 2 plant pathogenic bacterial species. Among these, activity against Phytophthora parasitica var. nicotianae and Sclerotinia sclerotiorum was the highest, with inhibition diameters of 56.4 and 56.3 mm, respectively. A necrotic spot method was used to determine that the fermentation broth inactivated TMV. When inoculating 10 rain after mixing fermentation broth with viral sap, necrotic spot formation was inhibited 93.88%. Treatment 24 h before or after inoculation provided 87.93 and 42.21% inhibition, respectively, of necrotic spot formation. Preliminary studies were conducted on stability of the fermentation broth. The antimicrobial substance in the fermentation broth was stable to temperature, light, and pH.