Research On Fermentation Conditions And Fermentation Bacteria Screening Of Microbial Phosphate Rock Powder Processing

The contradiction between the deficiency of high grade phosphate rock resources and the current increasing of phosphorus resource utilization is increasingly prominent in China.So far,the phosphate fertilizer industry ground phosphate rock is usually acidified to the calcium superphosphate,or is calcinated to calcium-magnesia phosphate fertilizer in high temperature,or the acidulated phosphorus is further extracted to monoammonium phosphate and diammonium phosphate.The biggest drawback of these methods is the high energy consumption and serious pollution.According to the above problem,this article adopts the method of microbial fermentation which make ground phosphate rock and producing strains ferment to screen the most suitable strains to ground phosphate rock fermentation,optimize strains growth conditions and determine the best fermentation temperature,fermentation moisture,the inoculation content,the activator content,explore fermentation processing to increase effective phosphorus content of ground phosphate rock,then provide new technical way,the theory support and the experimental data for reasonable utilization of low grade phosphate rock resources.In this paper,the main research contents and results are as follows:(1)Screening combination and the optimal ratio of combination strains.The research results show that when culture the phosphate-solubilizing bacteria,the rhizopus,the thamidium in combination,the growth speed of strains is fast,the diameter of strains is 7.54cm and the conidial production reaches 3.03×10~9 per ml.the proportion of each strains were analyzed in the optimal combination strains,and the research results show that when the proportion is 30%phosphate-solubilizing strains,35%rhizopus and 35%mould,conidial production is maximum,up to 3.10×10~9 per ml and acidity is strongest,pH up to 2.07,1.9 times than that of the original culture medium.(2)Research on the optimization of the growth conditions of strains.The results show that regarding 30%sodium nitrate,60%glucose respectively as nitrogen source and carbon source of culture medium,adding 2‰biological activator at the same time,cultivating 7 days in 30?environment can obtain higher conidial production.(3)Research on different fermentation conditions on the activation of the ground phosphate rock.Under five test factors the single factor analysis of ground phosphate rock fermentation is made,the results show that the best fermentation conditions which the ground phosphate rock is fermented with screened optimal combination strains is the fermentation temperature 25?,culture medium moisture content 70%,the inoculation content 4%and the activator content 0.36%.In orthogonal test of three factors and three levels,the optimum fermentation conditions are further determined.The highest effective phosphorus content is 10.87%when the fermentation temperature is 30?,culture time is 7 days and substrate moisture content is 70%.The biggest influence factor is the fermentation temperature,second is the culture time,the last is the substrate moisture content.