一株表面活性剂产生菌的分离及抑菌活性

【目的】研究分离得到的表面活性剂产生菌的产表面活性剂能力、分类地位和抑菌活性。【方法】采用血平板、油平板进行表面活性剂产生菌的分离,以排油圈法进行表面活性的测定;通过生理生化特性和16S rDNA序列相似性分析对BS1菌株进行初步鉴定;利用对峙培养法和菌丝生长、孢子囊形成、孢子萌发的抑制率测定研究其抑菌活性。【结果】从石油污染土壤中分离到的BS1菌株可产生表面活性剂,在分类学地位上属于假单胞菌属(Pseudomonas sp.)。BS1菌体、发酵上清液、挥发性物质对12种供试病原真菌均表现出一定的抑制作用。BS1菌体、发酵上清液对大豆疫霉菌(Phytophthora sojae)的抑制率最大,分别达到65.31%和95.93%。发酵上清液通过影响大豆疫霉菌菌丝生长、孢子囊形成、孢子萌发等方式抑制病原菌的正常生长,稀释20倍的发酵上清液依然具有明显的抑制作用。BS1菌株产生的挥发性物质对大豆菌核菌(Sclerotinia sclerotiorum)的抑菌效果最好,抑制率达到84.25%。【结论】BS1菌株在产生表面活性剂的同时,还具有生物防治作用潜力。

Isolation and antifungal activity of a biosurfactant-producing bacterium

Objective] The objective of this study was to examine the production of biosurfactant, taxonomic position and antifungal activity of the strain BS1. Methods] Biosurfactant-producing bacterium was isolated by hemolytic activity assay on blood agar plates and hydrolyzing oil activity estimation on oil agar plates. Oil spreading method was used to assay surface activity. The strain BS1 was indentified according to morphological features, physiological and biochemical characteristics and 16s rDNA sequences of the strain. Antifungal activity was tested by dual-culture method and the inhibiting effect on the the mycelium growth, sporagium formation and spore germination. Results] The strain BS1 of producing biosurfactant, isolated from the petroleum-polluted soil, was indentified as Pseudomonas sp.. The strain BS1, fermentation supernatant and the volatile compounds (VCs) exhibited inhibition activity on 12 kinds of plant pathogenic fungis. The strain BS1 and fermentation supernatant displayed significant inhibition to the Phytophthora sojae, the inhibitory rate was 65.31% and 95.93%, respectively. The fermentation supernatant of BS1 inhibited the growth of Phytophthora sojae by inhibiting mycelium growth, sporagium formation and spore germination, which had also remarkable inhibition even if it was diluted 20 times with pure water. VCs produced by strain BS1 had notable inhibiting effect against Sclerotinia sclerotiorum, and its inhibitory rate was 84.25%. Conclusion] The strain BS1 can produce surfactant and has the potential biocontrol.