湿热地区腐败燕麦青贮中霉菌的分离鉴定及生物学特性研究

Isolation,Identification and Biological Characteristics of Mold from Rotten Oat Silage in Hot and Humid Areas

明晰腐败燕麦青贮中霉菌种类和生物学特性对我国湿热地区燕麦青贮具有重要意义。从腐败的燕麦青贮中分离霉菌,利用形态学特征和分子生物学方法进行鉴定,并研究其生物学特性。结果表明:(1)共筛选出霉菌6株(LSO1~6),LSO1为钩状木霉(Trichoderma hamatum),LSO2为轮枝镰刀菌(Fusarium verticillioides),LSO3为毛霉属(Mucor sp.),LSO4为多变根毛霉(Rhizomucor variabilis),LSO5为Simplicillium aogashimaense,LSO6为散布韦斯特壳(Westerdykella dispersa)。(2)LSO1和LSO4菌株最适生长温度为30℃,LSO3菌株最适生长温度为25℃,LSO2、LSO5和LSO6菌株最适生长温度为28℃,6株霉菌均在4℃生长最慢。(3)LSO1和LSO4最适生长pH值为5,LSO2、LSO6菌株最适生长pH值分别为9和4,LSO3、LSO5菌株分别在pH值5~9、5~8时生长较好。(4)连续光照有利于LSO1、LSO3、LSO4和LSO6生长,不利于LSO2生长;完全黑暗有利于LSO2生长,不利于LSO1和LSO6生长;光暗交替不利于LSO3、LSO4生长。(5)6株霉菌均能利用多种碳源、氮源。LSO1、LSO3、LSO4和LSO6菌株最佳碳源是D-果糖,LSO2和LSO5菌株最佳碳源是葡萄糖;LSO1、LSO2、LSO4、LSO5、LSO6最佳氮源是牛肉膏,LSO3最佳氮源是酵母浸粉。(6)LSO1、LSO3、LSO4致死温度为75℃(10 min),LSO2、LSO5、LSO6致死温度分别为60℃(10 min)、65℃(10 min)、70℃(10 min)。

It is importantly significant to clarify the type and biological characteristics of molds in spoilage oat silage to prevent spoilage in oat silage from humid and hot areas of China.In this study,molds were isolated from rotten oat silage,identified using morphological features and molecular biological analyses,and their biological characteristics were studied.The aim was to establish a theoretical foundation for extending the shelf life of oat silage.The results showed that:(1)A total of six mold strains(LSO1—6)were selected.LSO1,LSO2,LSO3,LSO4,LSO5 and LSO6 were identified as Trichoderma hamatum,Fusarium verticillioides,Mucor sp,Rhizomucor variabilis,Simplicillium aogashimaense and Wester⁃dykella dispersa,respectively.(2)LSO1 and LSO4 strains exhibited optimal growth at 30℃,LOS3 at 25℃,LSO2,LSO5 and LSO6 at 28℃.All six strains exhibited the slowest growth at 4℃.(3)LSO1 and LSO4 preferred a pH of 5,LSO2 and LSO6 preferred pH 9 and 4 respectively,while LSO3 and LSO5 thrived between pH 5—9 and 5—8 respectively.(4)Continuous light favored the growth of LSO1,LSO3,LSO4 and LSO6,but hindered LSO2.Complete darkness promoted LSO2 growth,but hindered LSO1 and LSO6.Light-dark alternation adversely affected LSO3 and LSO4 growth.(5)All six strains could utilize various carbon and nitrogen sources.Optimal carbon sources were D-fructose for LSO1,LSO3,LSO4,and LSO6,and glucose for LSO2 and LSO5.The optimal nitrogen source for LSO1,LSO2,LSO4,LSO5,and LSO6 is beef extract,the optimal nitrogen source for LSO3 is yeast extract.(6)LSO1,LSO3,and LSO4 exhibited lethal temperatures of 75℃(10 min),while LSO2,LSO5,and LSO6 exhibited lethal temperature of was 60℃(10 min),65℃(10 min)and 70℃(10 min)respectively.