烟区土壤高效氨化芽孢杆菌菌株的筛选鉴定及特性研究

为提高有机肥中有机氮的分解效率，满足烤烟生长前期氮素需求，利用氨化细菌培养基从贵州烟区土壤中分离、纯化获得了5株氨化细菌菌株，通过纳氏试剂比色法测定培养液中的氨氮浓度，5株菌株的氨氮产量在297~460 mg/L之间；筛选出氨化作用最强的2株菌株，通过形态、生理生化特征、16S rRNA基因测序及系统发育分析，鉴定AMM-2菌株为Bacillus toyonensis，AMM-5为Bacillus mobilis。氨化特性研究显示，在pH 7.0的氨化细菌培养基中，30℃条件下培养48 h，2株菌产生的NH₄⁺-N浓度分别可达514和505 mg/L，在pH 4.0~10.0和25~30℃温度范围内均表现较强的氨化能力，其中AMM-5菌株的温度适应性更广、耐盐性更高。研究获得了分解有机氮能力强的芽孢杆菌菌株，为提高有机肥的肥效提供了菌株资源。

Screening,Identification and Ammoniation Features of High Effective Ammonifying Bacillus Strains Isolated from Tobacco-planted Soils

In order to improve decomposition efficiency of organic nitrogen in organic fertilizer and meet the nitrogen requirement of tobacco at the early growth stage,five ammonifying bacterial strains were isolated and purified from tobacco-planted soil in Guizhou using ammoniated bacterium medium.The NH4+-N concentrations in ammoniated medium of five strains were between 297 mg/L and 460 mg/L by the measurement of Nessler’s reagent method.Two ammonifying strains AMM-2 and AMM-5,with the highest ammonifying ability were identified as Bacillus toyonensis and Bacillus mobilis,respectively,based on the morphological characteristics,physiological and biochemical identification,16S rRNA gene sequencing and phylogenetic tree analysis.After incubation for 48 h at 30℃,the NH4^+-N concentrations of AMM-2 and AMM-5 in ammoniated medium(pH 7.0)were 514 mg/L and 505 mg/L,respectively.Good ammonifying abilities of the two ammonifying strains were observed under the condition of pH 4.0-10.0 and temperature 25-30℃,respectively.Comparing with AMM-2,AMM-5 showed the wider temperature adaptation and higher salt tolerance.The two Bacillus strains with high organic nitrogen decomposition ability,obtained in this study could provide desirable strain resources for enhancing manurial effect of organic fertilizer.