除草活性放线菌DN5发酵条件及发酵产物理化性质的研究

为了提高放线菌DN5发酵液活性物质的产量,通过单因子试验和正交试验,对其摇床发酵培养基成分及发酵条件进行研究;同时测定其发酵产物的性质.单因子试验结果表明:发酵培养基的最佳碳源为可溶性淀粉,氮源为硝酸钾,添加无机盐的种类为硫酸镁、硫酸亚铁和氯化钠时,放线菌DN5发酵液抑制活性较高.正交试验结果表明,发酵培养基各组分的最佳配比(质量分数)为:可溶性淀粉2.0%、硝酸钾0.15%、硫酸镁0.025%、硫酸亚铁0.001%、氯化钠0.075%、磷酸氢二钾0.075%.菌株DN5发酵的优化条件为:初始pH7.0,发酵时间96h,接种量1%,装液量80mL/250mL,温度28℃.菌株DN5发酵产物具有良好的热稳定性和光稳定性,在中性及弱碱性条件下较稳定,在4℃可储藏120d.杀草谱和作物安全性试验结果表明,DN5菌株发酵液对苘麻Abutilon theophrasti、萝藦Metaplexis japonica和铁苋菜Acalypha australis等的种子萌发有抑制作用.供试作物中,高粱Sorghum bicolor、玉米Zea mays和莴苣Lactuca sativa对其敏感;大豆Glycine max和小麦Triticum aestivum等对其不敏感.

Ferment Conditions and Physicochemical Characteristics of Fermentation Products of Actinomycete DN5 with Herbicidal Activity

In order to increase the productivity of substance of DN5 with herbicidal activity,the compositions of cultural medium and the culture conditions of DN5 were investigated by using the single factor and orthogonal design method.The characteristics of the active substance were tested.Results showed that the best carbon source was soluble amylum,the best nitrogen source was KNO3,and the inhibition rate of DN5 was the highest when added MgSO4、FeSO4 and NaCl.The best composition of cultural medium was as follow： soluble amylum 2.0%,KNO3 0.15%,MgSO4 0.025%,FeSO4 0.001%,NaCl 0.075% and K2HPO4 0.075%.The optimal ferment conditions was initial pH7.0,ferment time 96 h,inoculation rate 1%,medium capacity 80 mL/250 mL and temperature 28 ℃.It was relatively stable in alkaline and neutral environment and could be stored for 120 d under 4 ℃.Weed spectrum and safety to main crops were identified.Results showed that the ferment products of DN5 could inhibit seed germination of Abutilon theophrasti,Metaplexis japonica and Acalypha australis etc.Among the main crops,Sorghum bicolor,Zea mays and Lactuca sativa were sensitive to DN5,while Glycine max and Triticum aestivum were not.