Microbial Community Structure Analysis In Different Mixed Microbial Samples By PCR-DGGE Technology

As one of the most impotant technique in microbial community structure analysis,denaturing gradient gel electrophoresis (DGGE) has been widely used in different fields ofmolecular ecology. There are still a lot of potential applications in different areas to need us todevelop. In this paper, two different microbial communities structures were studied by DGGEtechnique, one comes from actuvated sludge of erythromycin wastewater treated bySequencing Batch Reactor Activated Sludge (SBR), another comes from Kefir grains. Thevariability of bacteria colony in Kefir fermentation process has also been detectedquantitatively by Real-Time Quantification PCR technique. The major results and conclusionsof this paper are summarized as follows:1. Firstly, measuring pH and COD of samples, the result showed it was feasible forerythromycin wastewater to treat by SBR; The dynamics of microbial community structure inerythromycin wastewater was studied by PCR-DGGE, the result showed there was a49.2%～73.5%similarity of microbial flora of different wastewater samples. DNA in main band ofDGGE profiles of microbial community in erythromycin wastewater was sequenced, showingThiobacillus sp., Uncultured bacterium, Flavobacterium sp. and Beta proteobacterium weredominant bacteria in SBR progress.2. The dynamics of microbial flora in kefir during fermentation was studied byPCR-DGGE, the result showed there was a80.6%～99.0%similarity of microbial flora ofdifferent kefir samples. DGGE profiles of microbial community structure in kefir grainsshowed the microbial community of kefir grains were not abundant,3different visible bandon the electrophoresis pattern of bacteria community were obtained, only1band on theelectrophoresis pattern of yeast community was obtained. The sequences of3differentvisible band on electrophoresis pattern of bacteria community had a high homology with the16S rDNA of lactic acid bacteria(LAB), these bacteria were Leuconostoc mesenteroides,Lactobacillus kefiranofaciens, Lactobacillus kefir respectively. The sequence of1band onelectrophoresis pattern of yeast community had a high homology with the16S rDNA ofTorulaspora delbrueckii.3. Total bacteria count in kefir during fermentation was detected by Real-TimeQuantification PCR. The result showed total bacteria count in kefir increased at early stage offermentation, and decreased at late stage of fermentation, there were small changes in totalbacteria count among different kefir samples during fermentation. 4. Kefir was studied by DGGE combined with microbial isolation method.3LAB and1yeast were isolated from kefir, and these microorganisms were Leuconostoc mesenteroides,Lactobacillus kefiranofaciens, Lactobacillus kefir and Torulaspora delbrueckii respectivelyby analysis of DGGE.