降解嗪草酮微生物菌剂的制备及稳定性研究

Preparation and stability analysis of the degradable metribuzin bacterium microorganism agent

通过富集培养分离出嗪草酮降解菌N1,降解菌在固体平板上培养,菌落大,表面粗糙,扁平,不规则,为质地软、稍有光泽的白色菌落,直径为5-7 mm。菌体细胞为杆状,末端方,成短或长链,菌体大小为1.0-1.2μm×3.0-5.0μm。将N1降解菌制成菌剂,用气相色谱法进行定量分析,通过单因素试验确定菌剂中载体配比、接种菌液量、加入营养液量、发酵时间、烘干温度等影响因子的优势条件,设计正交试验确定最优菌剂制备条件：m（豆粕）∶m（麦麸）∶m（木屑）∶m（硅藻土）比例为60∶20∶15∶5,接种菌液量为15%,营养液量为10%,发酵时间为48 h,烘干温度为30℃。在上述条件制备的菌剂对嗪草酮的降解率为79%。该菌剂在25℃下保存50 d后对嗪草酮仍有较高的降解效果。

This paper intends to present our study of the preparation method and the stability analysis of the degradable metribuzin bacterium micro-organic agent in screening and isolating the metribuzin degradable bacteria N1 by using a specific enrichment carrier for further preparation of the micro-organic bacterium degradation agent. As the result of our investigation and experiments,we have isolated a highly efficient strain of metribuzin degrading bacterium N1 from the pond sludge through sewage-treating in a pesticide plant by taking metribuzin as the sole nitrogen source,which was identified as bacillus according to its physiological and biochemical properties. And,next,we have managed to clarify its morphological features. The cells of the bacteria can be described as rod-shaped,with its size being 1. 0-1. 2 μm ×3. 0-5. 0 μm in a coryne or coccoid form with no spore inside.The color of the bacteria is milk-white with bright luster. Its colonies are large and rough in appearance,with its textures being flat,soft and irregular in shape and its cell diameter being 5-7mm. Further studies help us to find the cells of bacillus tend to grow up into some applanation,round colonies on the cultured base of ISP2. Detailed quantitative analysis has also helped us to identify the optimal conditions of preparation factors,such as the carrier composition,the vaccination bacterium fluid,adding nutrient solution,the determination of the fermentation time and drying temperature,etc. with the method of gas chromatography at a certain degradation rate. We have also conducted an orthogonal experiment comprising five factors and four levels,from which we have detected the carrier consisting of 60% soybean meal,20%wheat bran,15% sawdust and 5% celite ratio in the optimum recipe. The optimal individual factors should include the following factors,such as 15 m L of vaccination bacterium fluid,10 m L of the nutrient solution addition and 48 hours of fermentation time.The optimal drying temperature should be set on 30 ℃. The degradation rate of the metribuzin degradation bacterium being cultivated under the mentioned condition is 79%. And,finally,the stability test of aforementioned microorganism bacterium degradation agent let us conclude that it can preserve good stability for 50 days at 25 ℃. In addition,the degradation function of the agent proves to last a few more days after exhibition.