Study On Structures And Characteristics Of Desulphurization Bacterial Community For Removing SO₂

Biological flue gases desulfurization is a new way on the progress of flue gas desulfurization at home and overseas currently. The study of microbial species composition and community structure has important values to analysis biochemical reaction process, which can gain some basic experience to optimize the technological parameters and improve efficiency for removing SO2. A desulphurization bacterial community with excellent ability for removing SO2 was obtained with this methods domesticating bacteria sample from oxidation ditch of city sewage treatment plant over 7d with low concentration SO2 gas.On the basis of the achievements obtained by the task team before, we want to know more about microbial species composition and community structure and their dynamic changes during domestication, Meanwhile, the biodegradation activity of SO2 by desulfurization function strains was studied. A desulphurization bacterial community with excellent ability for removing SO2 (efficiency can reach 95%) was obtained with inductive domestication over 7d with low concentration SO2 gas. The community had good stability to SO2 degradation during 14 d domestication.The bacterial species were identified by the method combining isolated culture and 16S rRNA gene sequencing technology, The results indicated that,23 strains were isolated from 7 d desulphurization bacterial community belong to 10 species, the diversity of microorganisms was very abundant and Rhodococcus erythropolis were predominant, constituting 43% of the total strains isolated; 22 strains were isolated from 14 d desulphurization bacterial community belong to 8species, the diversity of microorganisms was declined and Pseudomonas putida were predominant, constituting 32% of the total strains isolated. The community structure varied significantly in domestication process during which some species kept stable while others were replaced by new species gradually.This research is the first to show that 13 species of bacteria(Rhodococcus erythropolis、Microbacterium oxydans、Pseudomonas putida、Sphingomonas koreensis、 Acinetobacter junii、Enterobacter ludwigii、Brevundimonas aurantiaca、Staphylococcus saprophyticus、Micrococcus luteus、Enterococcus faecium、Microbacterium esteraromaticwn、Acinetobacter johnsonii and Kocuria rosea) associated with removing SO2, they were isolated from 7 d and 14 d desulphurization bacterial community. The first to show that six species (Rhodococcus erythropolis、Microbacterium oxydans、 Sphingomonas koreensis、Pseudomonas putida、Acinetobacter junii、Acinetobacter johnsonii) can degraded SO32- strongly were major functional species with removing SO2.The major functional species grows fast, strong adaptability and could stably grew and passage in continuous domestication process, so as to maintain a steady desulfurization properties. And the main metabolic product was SO42-, as well as small amount of elemental sulfur as from Rhodococcus erythropolis、Acinetobacter junii and Acinetobacter johnsonii. The 13 species are coccus and bacilli,<5 μm in diameter ascoccus, and 0.2-1.5μm×1.0-5.Oμm as bacilli, seven species are gram positive bacterium and six species are gram negative.Based on the research of SO32- degradation by the single desulfuration bacteria and desulphurization bacterial community containing mixed bacteria, the single desulfuration bacteria had a weaker degradation activity. The result showed that had a certain synergy between mixed bacteria, so that degraded quickly and efficiently.The research of desulphurization functional bacteria and their basic characteristic provides a lot of microbiology resource and theoretical basis for biological SO2 flue gas desulfurization technology.