除草活性菌株HZ-011发酵培养基筛选及其条件优化

Screening of fermentation medium for herbicidal active strain HZ-011 and optimization of its conditions

【目的】明确除草活性菌株HZ-011的发酵培养基各因素配比及最适发酵条件,为该菌作为除草剂的研发和农田应用提供理论依据。【方法】以产孢量为目标,通过固体培养基筛选确定菌株HZ-011生长的基础培养基;采用单因素试验优化菌株HZ-011的发酵培养基和最佳发酵条件;利用中心组合设计(Central composite design,CCD)原理对菌株HZ-011的液体培养基成分及配比进行优化;通过响应面法分析培养基各成分间的交互作用;用菌株HZ-011发酵液对盆栽杂草(藜、密花香薷、冬葵和反枝苋)进行致病性试验。【结果】经过优化,菌株HZ-011的培养基最佳配比为蔗糖48.744 g/L、蛋白胨15.626 g/L、NaCl 0.214 g/L和K_(2)HPO_(4)0.428 g/L,最佳发酵条件为pH 7、温度25℃、培养时间5 d、装液量180 mL和转速180 r/min。盆栽试验结果表明,菌株HZ-011对藜和反枝苋全部致死,对密花香薷的致病率为75%,对冬葵的致病率为40%。【结论】优化后的培养基提高了菌株HZ-011的产孢量,为该菌株应用于农田杂草生物防治打下基础。

【Objective】Todetermine the ratio of various factors of the fermentation medium and the optimal fermenta-tion conditions of strain HZ-011 that has herbicidal effect on weeds,andprovide theoretical basis for development of HZ 011 herbicide and application in farmland.【Method】The basic medium for the growth of strain HZ-011 was selected by solid medium with the goal of spore production.Single factor experiment was used to optimize the fermentation medium and fermentation conditions of strain HZ-011.The liquid medium composition and ratio of strain HZ-011 were optimized by using the principle of central composite design(CCD).The interaction between the components of the medium was analyzed by response surface methodology.The pathogenicity of potted weeds(Chenopodium album,Amaranthus retro-flexus,Elsholtzia densa and Malva crispa)was tested with HZ-011 fermentation broth.【Result】After optimization,the optimal proportion of culture medium of strain HZ-011 was sucrose 48.744 g/L,peptone 15.626 g/L,NaCl 0.214 g/L and K_(2)HPO_(4)0.428 g/L.The optimum fermentation conditions were pH 7,temperature 25℃,culture time 5 days,liquid loa ding 180 ml and rotating speed 180 r/min.The results of pot experiment showed that strain HZ-011 killed all C.album and A.retroflexus,and the pathogenicity of E.densa was 75%,then the pathogenic rate of winter sunflower was 40%.【Conclu-sion】The optimized medium increased the spore production of strain HZ-011,which lays a foundation for the application of the strain in the biological control of farmland weeds.