蚕沙堆肥过程中解磷解钾细菌的分离与鉴定

Isolation and Identification of Phosphate- and Potassium-solubilizing Bacteria from Fermented Silkworm Excrement

磷和钾是作物生长必需的营养元素。我国土壤中磷钾元素主要以难溶性形式存在,作物可利用率低。微生物在土壤的磷钾循环利用中起着重要作用,能将难溶的磷钾元素释放出来供作物吸收利用。利用选择性培养基从蚕沙堆肥发酵高温期产物中筛选获得一批具有溶磷解钾活性的菌株,并对其中10株菌株进行分类鉴定和溶磷解钾能力分析。结果表明,这10株蚕沙分离菌分别为产气肠杆菌、巨大芽孢杆菌、沙福芽孢杆菌、短小芽孢杆菌和枯草芽孢杆菌,对逆境有一定的耐受性,都可以在50℃高温和pH 5~9条件下生长,其中有3株枯草芽孢杆菌能耐受7%NaCl培养。巨大芽孢杆菌OP6具有较强的释放磷酸钙中磷的能力,而除OP3外的其他9个菌株均有较强的释放钾长石粉中钾的能力。研究结果解析了蚕沙有机肥肥效的微生物学基础,也为后续开发功能微生物提供了素材。

Phosphorus and potassium are essential nutrients for crop growth.The largest proportions of P and K in soil are insoluble and their availability to crop is low.Microorganisms play an important role in the recycling of phosphorus and potassium in soil,which can release the insoluble phosphorus and potassium elements for crop absorption and utilization. With selective medium,a group of microbes with phosphorus and potassium releasing ability were isolated from silkworm litter compost at high temperature fermenting stage.Within them,ten isolated strains had been classified and identified for their phosphorus and potassium releasing ability.Results showed that these 10 bacteria strains belong to Enterobacter aerogenes,Bacillus megaterium,Bacillus safensis,Bacillus pumilus and Bacillus subtilis,respectively.These strains have certain tolerance to environmental stress,being able to grow under 50℃ high temperature and pH 5to 9.Three Bacillus subtilis isolates are tolerant to culture under 7% NaCl.Within the 10 strains,Bacillus megaterium OP6 had strong ability in releasing phosphorus from calcium phosphate,and the rest nine strains exhibited good ability in releasing potassium from potassium feldspar powder.These data serve as a reference to clarify microbial basis of the efficacy of silk-worm excrement organic fertilizer,and also provide material for subsequent development of functional microbial bacteria.