2种致病疫霉拮抗真菌混合发酵及抗菌物质稳定性研究

Mixed Fermentation of Two Antagonistic Fungi Against Phytophthora infestans and Stability of Anti-fungi Substances

为获得防治马铃薯晚疫病稳定的生防制剂,对能够有效抑制致病疫霉的拮抗菌梨黑斑病菌LH-03和白菜黑斑病菌BH-09混合发酵的可行性及发酵条件进行了确定和优化,同时对混合发酵产物的抗菌稳定性进行了初步研究.结果表明,2种真菌之间无拮抗作用,可进行混合发酵,并且发现混合发酵后可有效提高2种真菌发酵液的抑菌活性;混合发酵的最佳发酵条件为pH 6.29,25℃、黑暗、静置、培养4d,在此条件下所得发酵产物对致病疫霉的抑菌率可达92.15%,显著高于2种拮抗菌单独发酵液的抑菌效果.混合发酵液经不同温度及不同pH值处理后,其抑菌活性基本保持不变或略有下降,其中在121℃高温处理下抑菌率仍可达到66.78%,在pH 2时抑菌活性最低,但仍达到了68.67%.混合发酵液中的抗菌物质具有很强的热稳定性及较强的耐强酸和强碱性,有良好的应用潜力.

To obtain the stable biocontrol preparation for controlling potato late blight,the feasibility of mixed fermentation for antagonistic fungi Alternaria alternate LH-03 and A.brassicae BH-09 against growth of Phytophthora infestans and the fermentation conditions were investigated,and then the stability of antagonistic substance in fermentation filter was tested in this experiment.The results showed that there were no antagonistic effects for two antagonistic fungi.The mixed fermentation could increase the anti-fungi activity to P.infestans.The optimized conditions for mixed fermentation were pH 6.29,25 ℃,standing culture for 4 days in the dark.Inhibition rate of fermentation liquid at optimized condition was up to 92.15% and stronger than that of two fungi fermentation independently.The fermentation product at optimized condition after treatment with different temperature and pH,its anti-fungi activity remained basically unchanged or declined slightly,especially for the inhibitory rate could reach 66.78% with high temperature treatment at 121 ℃,and 68.67% with pH 2 treatment,respectively.It is indicated that the fermentation product at optimized condition had a great potential in control potato late blight in future since it displayed strong thermal stability and well resistance to superacid and strong alkali.