一株有抑菌活性的酸枣内生菌的分离及发酵条件优化

Isolation an endophytic bacterial strain with antifungal activity from wild jujube and optimal fermentation conditions

研究酸枣叶片内生菌中的菌种鉴定及发酵条件的优化。采用组织分离法和研磨涂布法从酸枣叶片中筛选内生菌,对所分离的内生菌的发酵液进行抑菌活性测定,选出对七种人体病原菌有抑菌活性的内生菌,并对其发酵条件的优化;将抑菌圈的大小作为指示,对内生菌C-13-1发酵条件的碳源、氮源和发酵时间时间进行单因素优化。结果表明:从陕北酸枣叶片内筛选出23株内生菌中,其中10株对七种人体常见致病菌有一定的抑菌活性,其中菌株C-13-1对七种人体常见致病菌抑菌圈直径均大于10 mm,对柠檬色葡萄球菌(Staphylococcus citreus)的抑菌圈达36 mm,抑菌活性较强。菌株C-13-1发酵的最佳碳源为蔗糖;最佳氮源为硝酸钠;最佳发酵时间为7 d。研究表明,酸枣叶片内生菌中蕴含着较为丰富的抗菌活性物质,是开发天然抗菌药物的潜在资源。

The purpose of the study was to identify the endophytic microbes in the leaves of wild jujube. By using tissue separation and grinding coated method the endophytes from Zizyphus jujube＇s leaves were screened out.The antibacterial activities of seven human common pathogenic bacterium in fermented liquid of endophytes were detected; the single fermentation conditions of strain C-13-1,including carbon source,nitrogen source and time,were optimized according to the size of inhibition zone. Results show that 23 strains from northern shaanxi wild Zizyphus jujube＇s leaves were screened out; ten of them have antibacterial activity to seven human common pathogenic bacteria with different degrees. The strain C-13-1＇s antibacterial circle diameter was greater than 10 mm to the seven pathogenic bacteria,and reach 36 mm to Staphylococcus citreus. The best carbon source of strain C-13-1 was cane sugar; the best nitrogen source was sodium nitrate; the best fermentation time was 7 d. Study shows that the endophytic bacteria in wild Zizyphus jujube＇s leaves contain abundant of antimicrobial substances and are the potential resources for the development of natural antimicrobials.