纤维素降解固氮芽孢杆菌的筛选和鉴定

Screening and identification of cellulase producing nitrogen-fixing bacillus

为了筛选利用纤维素的高效固氮芽孢杆菌作为生产生物固氮菌肥料的菌株,将土壤样品悬液在80℃水浴加热10min,采用以微晶纤维素为碳源的无氮培养基富集和分离纯培养;用DNS法测糖、微量凯氏定氮法定氮测定纤维素酶活性和固氮效率;通过盆栽试验观察菌液对黄瓜植株生长的影响;通过形态观察、生理生化鉴定和16SrDNA比对分析对菌种进行鉴定.实验筛选到生长较快、纤维素酶活性和固氮效率较高的利用纤维素的固氮芽孢杆菌菌株CX21,该菌株在黄瓜盆栽试验中可以达到对照处理施用化学氮肥的等同效果;鉴定结果表明该菌株属于胶质类芽孢杆菌Paenibacillusmucilaginosus.

In order to screen cellulase producing efficient nitrogen-fixation bacilli as bio-fixing bacteria for industrial manufacture, the soil suspension in the 80℃ water-bath for 10 min , was enriched and isolated cultivation by nitrogen-free microcrystalline cellulose culture. DNS method and micro Kjeldahl method were used to determine the cellulose activity and nitrogen fixation efficiency. Inoculation effect was tested with cucumber potted experiment. Strain identification was carried out based on the morphology, physiology, biochemical test and 16S rDNA sequences analysis. The cellulase producing nitrogen-fixation bacillus CX21 with growing quickly, relative high cellulase activity and N-fixation efficiency, was isolated. Besides, the strain could reach the equivalent effect of chemical nitrogen fertilizer. The identification results showed that the strain belong Paenibacillus mucilaginosus.