抗瓜果腐霉芽孢杆菌优良菌株的筛选及生物学特性

为获得具有高效抗菌活性的芽孢杆菌用于生物防治与果蔬保鲜,从柠檬、葡萄、红枣、酸奶、腐乳、豆瓣酱、哈尔滨红肠等26种食品样品中分离获得204株芽孢杆菌,通过对峙培养法,初筛得到62株抗瓜果腐霉(P.aphanidermatum)的菌株,选取其中抑菌效果明显的4株菌株,采用牛津杯扩散法经复筛得到1株显著抗瓜果腐霉的芽孢杆菌L-NM62,其发酵上清液对瓜果腐霉的抑菌圈直径达到(24.54±0.13)mm。菌株L-NM62经形态学、生理生化和16S rDNA序列分析,被鉴定为枯草芽孢杆菌L-NM62(Bacillus subtilis L-NM62)。进一步研究枯草芽孢杆菌L-NM62的生物学特性,发现该菌株的最适生长温度37℃,最适pH值7.5,最适接种量1.0%,并测定了该条件下枯草芽孢杆菌L-NM62的生长曲线。在此基础上,考察枯草芽孢杆菌L-NM62的抗菌谱,结果表明,枯草芽孢杆菌L-NM62具有广谱的抗菌活性,尤其对霉菌具有高效广谱的抗菌效果,显示出了很好的潜在开发应用前景。

Screening and Biological Characteristics of Bacillus sp. with High Anti-fungal activity against Pythium aphanidermatum

Pythium aphanidermatum is known as an important plant pathogenic fungus that can cause various types of crops rot and damping off,as well as results in spoilage of fruits and vegetables,thus leading to great loss of agricultural production and food industry.In order to obtain spore-forming bacteria with anti-fungal activity for fruit and vegetable preservation and biological control,we have screened 204 strains of spore-forming bacteria isolated from 26 kinds of foods,such as lemon,grape,Chinese date,yogurt,fermented bean curd,Harbin sausage,bean paste and other food samples.Totally 62 strains of sporeforming bacteria were assessed by confrontation culture tests to reveal strong anti-fungal activity against P.aphanidermatum.The fermentation supernatants of 4 strains with stronger anti-fungal activity through Oxford cup plate assay method were tested for their anti-fungal activity,and L-NM62 revealed the strongest anti-fungal activity against P.aphanidermatum.The inhibition zone of cell free supernatant was(24.54 ± 0.13) mm in diameter.According to the characteristics of morphology,physiology and biochemistry tests,and the comparison of 16S rDNA sequence,strain L-NM62 was identified as Bacillus subtilis.Further study of L-NM62 on physiology characteristics showed that the optimal growth temperature,pH and inoculums were 37 ℃,7.5 and 1.0%.Under these optimal conditions,L-NM62 had a wide anti-fungal and antibacterial activity and presented a potential prospect.