小串链霉菌XG40菌株发酵条件优化及其次生代谢产物性质研究

Optimization of Fermentation Conditions and Properties of Secondary Metabolite of Streptomyces catenulae XG40

为进一步提高小串链霉菌Streptomyces catenulae XG40对琯溪蜜柚黑斑病的生防效果,通过碳、氮源单因子试验、正交试验和发酵条件优化,以菌浓度和抑菌带宽为指标确定其最佳发酵培养基配方和发酵条件。进一步用乙酸乙酯提取菌株XG40发酵液中的活性物质并测定其理化性质。结果表明,菌株XG40最佳发酵培养基配方为玉米粉50 g/L,黄豆粉9 g/L,酵母粉6 g/L,NaCl 0.5 g/L,K_(2)HPO_(4)0.5 g/L,Mg SO_(4).7H_(2)O 0.5 g/L,Fe SO_(4).7H_(2)O 0.01 g/L;最佳发酵条件为初始p H 7.0,温度28℃,装液量100 mL/500 mL,接种量7%,转速160 r/min,发酵时间6 d。菌株XG40发酵液的活性物质对蜜柚黑斑病菌菌丝生长有很强的抑制作用,该活性物质较耐酸碱和短时间(180 min)紫外线照射,耐贮性高,但高温对其抗菌活性有一定的影响。小串链霉菌XG40可为开发针对蜜柚黑斑病的生物农药提供新的原材料,其活性物质抑菌效果良好,稳定易保存,可为进一步开发利用奠定基础。

To further improve control efficiency of Streptomyces catenulae XG40 on Phyllosticta citriasiana,the optimal ingredients of fermentation medium and suitable fermentation conditions in shake flask were determined by single factor and orthogonal experiments with mycelia quantity and inhibition zone as indicators.Then,the antifungal substances were crudely extracted from the cultural filtrate of XG40 with ethyl acetate and their physicochemical properties were determined.The results showed that the optimal fermentation medium formula for antagonistic strain XG40 was corn flour 50 g/L,soybean meal 9 g/L,yeast powder 6 g/L,NaCl 0.5 g/L,K_(2)HPO_(4) 0.5 g/L,MgSO_(4)·7H_(2)O 0.5 g/L,and FeSO_(4)·7H_(2)O 0.01 g/L.The optimum fermentation conditions were initial pH value 7.0,temperature 28℃,loading volume 100/500 m L,inoculation amount 7%and rotational speed 160 r/min,and fermenting for six days.The crude extract by ethyl acetate exhibited high inhibition activity on the mycelial growth of P.citriasiana.Crude extract from strain XG40 had good stability to UV-irradiation at short time (180 min),acidic and alkali,and high storage stability in methanol solution,while high temperature had a certain impact to its inhibition activity.The above results indicated that the antagonistic strain XG40 could provide new raw materials for biological pesticides against P.citriasiana.The active component has good antifungal effect,and is stable and easy to preserve,which has a potential for further development and utilization.