本文選題：北極海洋沉積物 + 低溫硝化細(xì)菌��； 參考：《青島大學(xué)》2017年碩士論文

【摘要】：隨著我國(guó)城市化的快速發(fā)展,城市用水量也隨之大幅增高,如何提高污水處理效率,保障水環(huán)境質(zhì)量成為城市發(fā)展的重要課題。寒冷地區(qū)冬季低溫污水的生物處理長(zhǎng)期存在著處理效果差、難以達(dá)標(biāo)排放等難題,這主要是由于低溫對(duì)活性污泥的吸附沉降性能和微生物的生長(zhǎng)發(fā)育等均有顯著影響。因此,分離高效的低溫硝化細(xì)菌并用于低溫污水的處理,是解決我國(guó)北方地區(qū)冬季污水廠出水水質(zhì)難以達(dá)標(biāo)的有效方法之一。極地特殊的環(huán)境與氣候造就了獨(dú)特的極地微生物生態(tài)系統(tǒng),是微生物新菌種資源的寶庫(kù)。根據(jù)菌落形態(tài)特征,利用4種硝化細(xì)菌篩選培養(yǎng)基從12個(gè)站位的北極海洋沉積物中分離篩選,并獲得16S rRNA基因有效序列的低溫硝化細(xì)菌達(dá)81株;基于16S rRNA基因的相似性分析與系統(tǒng)發(fā)育分析表明,分離到的菌株分屬于細(xì)菌域的4個(gè)門(mén)、4個(gè)綱、8個(gè)目、16個(gè)科、22個(gè)屬、30個(gè)種,其中γ-變形桿菌綱(γ-Proteobacteria)占大多數(shù);有1株菌株與模式菌株的16S rRNA基因序列相似性小于97%,為潛在的新種。對(duì)不同屬的代表菌株的生理生化測(cè)定表明,大多數(shù)菌株具有產(chǎn)蛋白酶、脲酶和β-半乳糖苷酶等胞外水解酶和利用葡萄糖、甘露醇和麥芽糖等各種碳源生長(zhǎng)的能力。對(duì)18株菌株的溫度和鹽度生長(zhǎng)范圍的測(cè)定表明,大多數(shù)硝化細(xì)菌的溫度和鹽度生長(zhǎng)范圍在0-30℃和0-90,大部分菌株最適溫度為20℃,最適鹽度為15,既能滿(mǎn)足低溫下菌株保持較高的生長(zhǎng)活性,又具有較廣的對(duì)鹽度適應(yīng)范圍,對(duì)環(huán)境有很好的適應(yīng)性。將對(duì)溫度和鹽度適應(yīng)能力較強(qiáng)的菌株接種到篩選液體培養(yǎng)基中,篩選出生長(zhǎng)情況較好的菌株R14-ZY-5、CC6-YX-43、NB04-YY-61、CC6-ZY-68、CC6-YY-73和CC6-YY-74,并分別對(duì)其進(jìn)行模擬污水的硝化與反硝化測(cè)試,經(jīng)測(cè)試菌株R14-ZY-5和CC6-YY-74具有較好的脫氮能力,可進(jìn)行混合菌群的構(gòu)建。此外,從2株細(xì)菌CC6-ZY-68和CC6-YY-74中成功克隆到反硝化途徑的關(guān)鍵酶基因nirS。選擇菌株R14-ZY-5和CC6-YY-74構(gòu)建混合菌群,并分別研究C/N、溫度和鹽度對(duì)其脫氮效果及COD去除率的影響。結(jié)果表明,混合菌群在C/N為8-14均具有較好的脫氮能力,在C/N=11時(shí)處理效果最好,48 h時(shí)NH4+-N去除率可達(dá)93.41%,NO3--N去除率可達(dá)99.96%;當(dāng)C/N=11時(shí),菌群在溫度為5℃-20℃均具有較高的脫氮能力,48 h時(shí)去除率相差甚微。在溫度為15℃時(shí)處理效果最好,48 h時(shí)NH4+-N去除率達(dá)91.70%,NO3--N去除率達(dá)99.96%,COD去除率達(dá)87.28%;菌群在鹽度為15-45的范圍內(nèi)均具有較好的脫氮能力,在鹽度為30時(shí)脫氮處理效果最好,48 h時(shí)NH4+-N去除率達(dá)92.57%,NO3--N去除率達(dá)99.96%,COD去除率達(dá)91.35%。本研究將為北方地區(qū)寒冷季節(jié)低溫生活污水的生物處理提供新的菌種資源,并為今后將其運(yùn)用到工程實(shí)踐中提供了基礎(chǔ)資料和科學(xué)依據(jù)。
[Abstract]:With the rapid development of urbanization in China, the amount of urban water consumption has also increased significantly. How to improve the efficiency of sewage treatment and ensure the quality of water environment has become an important topic of urban development. The biological treatment of low temperature sewage in cold region has some problems such as poor treatment effect and difficulty in discharging. This is mainly due to the significant influence of low temperature on the adsorption and settling performance of activated sludge and the growth and development of microorganisms. Therefore, it is one of the effective methods to separate high-efficient low-temperature nitrifying bacteria and to treat low-temperature sewage. The special environment and climate of the polar region create a unique polar microbial ecosystem, which is the treasure house of new microbial species. According to the morphological characteristics of the colony, 81 strains of low-temperature nitrifying bacteria with effective 16s rRNA gene sequence were isolated and screened from 12 stations of Arctic marine sediments by four kinds of nitrifying bacteria screening medium. The similarity analysis and phylogenetic analysis based on 16s rRNA gene showed that the isolated strains belonged to 4 phyla, 4 classes, 8 orders, 16 families, 22 genera and 30 species, of which 緯 -Proteobacteria accounted for the majority. The sequence similarity of 16s rRNA gene between one strain and the model strain is less than 97%, which is a potential new species. The physiological and biochemical tests of the representative strains of different genera showed that most strains had the ability to produce protease, urease and 尾 -galactosidase, and to grow with various carbon sources such as glucose, mannitol and maltose. The growth range of temperature and salinity of 18 strains was determined. The results showed that the temperature and salinity of most nitrifying bacteria ranged from 0-30 鈩，

本文編號(hào)：1925176