土壤中解钾菌K02的筛选、鉴定及培养条件优化

Screening,Identification and Culture Condition Optimization of Potassium-Soluble Bacteria K02 in Soil

解钾微生物是能够在土壤或纯培养条件下,将含钾矿物如长石、云母等不能被作物吸收利用的矿物态钾分解,并产生水溶性钾的微生物。利用以钾长石粉为唯一钾源的硅酸盐细菌选择性培养基,采用梯度稀释分离法平板划线对番茄土壤中的钾细菌进行筛选。利用原子吸收火焰分光光度法测定钾细菌培养液中可溶性钾的含量,筛选高效解钾菌株。通过形态观察和16S rDNA序列GenBank比对,同时利用clustalx和MEGA 4.0等相关软件构建系统进化树对解钾能力最强的菌株K02进行鉴定,初步鉴定该解钾菌为胶质类芽胞杆菌(Paenibacillus mucilaginosus);利用单因素试验法对K02菌株培养基组分及发酵条件进行优化,初步确定菌株K02最佳培养基组分以解钾复筛培养基为基础,其碳源、氮源及无机盐以可溶性淀粉1%、酵母膏0.2%、K2HPO40.05%为最佳;菌株K02最佳发酵条件:培养温度为30℃,培养时间为48 h,培养基装量为50 mL/250 mL,培养基初始pH值为7.5,接菌量为5%,这一结果为解钾菌肥的研制和生产提供参考。

Potassium-soluble microbes are those that can decompose potassium-bearing minerals such as feldspar,mica etc,which cannot be absorbed and used by crops,into water-soluble potassium in soil or under pure culture conditions.Potassium bacteria from tomato soil were screened using gradient dilution separating method on plate scratching method with potassium feldspar powder as the only potassium source in silicate bacteria selective medium.The content of soluble potassium in the solution of culture medium of potassium bacteria was determined by atomic absorption flame spectrophotometry to screen high-effective potassium-soluble strain.Through morphological observation and Gen Bank comparison of 16S rDNA sequence,at the same time phylogenetic tree was constructed using clustalx and MEGA 4.0 and other related software to identify the strain K02 with the strongest potassium resolution ability,which was initially identified as Paenibacillus mucilaginosus.Single factor testing method was used to initially optimize the fermentation conditions of K02 strain.It was initially confirmed that the optimal medium composition of K02 was based on potassium rescreening medium,and the carbon source,nitrogen source and inorganic salts were soluble starch 1%,yeast extract 0.2%and K2HPO40.05%;The optimal fermentation conditions of K02 were initially determined as follows:the culture temperature was at 30℃,the culture time was 48 h,the medium loading volume was 50 mL/250 mL,the initial pH was 7.5,and the inoculation volume was 5%.This result provided a theoretical basis for the development and production of potassium soluble bacterial fertilizer.