Screening And Identification Of Acid-producing Bacteriaand Thenmophilic,basophilic Filamentous Fungi

Microorganism is one of the most important biological resources on the earth,also the biological basis for the industrial biotechnology.Therefore,by screening,identification and classification of acid-producing strains,thermomyces and basophilic filametous fungi in this study,it can contribute to further develop and utilize this kind of microbial resources.Among the 3465 strains of bacteria from Culture and Information Center of Industrial Microorganisms of China Universities(CICIM-CU),490 strains which can produce acids have been screened.According to the ratios of the diameters of the yellow circles and those of the colonies of acid-producing strains,the largest ratios of the diameters(Ratio is greater than or equal to 3.0)of 90 acid-producing bacteria were selected from 490 strains of bacteria to analyze the acid-producing ability.And at the same time,the 16S rDNA of 90 acid-producing bacteria were also amplified by PCR and sequence.The results of sequences analysis showed that 90 strains of acid-producing bacteria belonged to 17 genera,the highest acid-producing strain is Bacillus licheniformis(B0415)in the Bacillus.And then it was chosen for shakeflask fermentation,the organic acids in their fermentation broth were detected by HPLC.The result showed that these organic acids include acetic acid,lactic acid,pyruvic acid,citric acid,pyruvic acid,malic acid,the higher percentage is malic acid,it is used to ferment to produce the reseach of malic acid laid.the foundation for the next step.76 soil samples were collected from South Africa.Through the pretreatment of the sample,enrichment culture and dilution separation method,50 thermophilic filamentous fungi and 110 basophilic filamentous fungi were isolated from these samples.By further studying the amount of microorganisms from different soil samples,it was found that the most of thermophilic and basophilic filamentous fungi were isolated from high-temperature composting and seaside soils with alkaline pH levels,respectively.Simultaneously,ITS regions of the 80 filamentous fungi isolates were amplified by PCR and sequenced,which showed that 30 strains of thermophilic filamentous fungi belong to 10 genera and 15 species,and 50 strains of basophilic filamentous fungi belong to 12 genera and 25 species.On the basis of the identification results of the ITS,one strain from each genus,including Aspergillus,Mucor,Thermomyces,Penicillium,Rhizomucor,Talaromyces and Fusarium,was separately selected to analyze their colonial characteristics and microscopic characteristics.And further analysis and constructing phylogenetic tree,found that six species of Thermomyces dupontii,Talaromyces cylindrospora,Thermomucor indicae-seudaticae,Fusarium keratoplasticum,Fennellomyces linder i and Nectria haematococca have not been present in China.At the same time,because of the alkali resistant ability of Fusarium keratoplasticum is the strongest,and found that the strain has the ability to produce lipase,so the follow-up study will use the strain as the reseach of lipase-production.