本文關(guān)鍵詞：氟樂(lè)靈降解細(xì)菌D8的分離、鑒定與降解特性的研究　出處：《塔里木大學(xué)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 氟樂(lè)靈 分離鑒定 蠟狀芽孢桿菌 生物降解 降解途徑

【摘要】：氟樂(lè)靈是一種廣泛使用的二硝基苯胺類(lèi)選擇性芽前除草劑,主要用于甜菜、棉花、番茄等40多種作物及果園、林業(yè)苗圃等防除一年生禾本科雜草及部分雙子葉雜草。因具有廣譜性、性質(zhì)和效果穩(wěn)定、持效期長(zhǎng)等特征,在世界范圍內(nèi)得到廣泛的推廣及使用,但其具有淋溶性差的特點(diǎn),在土壤中能被土粒吸附而積聚在表土層,不易被雨水沖刷流失或淋溶至心底土層,殘留在土壤中,少量的氟樂(lè)靈在土壤中殘留可達(dá)兩年之久,且對(duì)作物的出苗率和生長(zhǎng)有影響,對(duì)生態(tài)環(huán)境和后茬作物都有一定的危害。本文針對(duì)氟樂(lè)靈殘留污染問(wèn)題研究其微生物降解技術(shù),采用稀釋分離培養(yǎng)法篩選氟樂(lè)靈高效降解菌,選取降解能力最優(yōu)的一株菌株進(jìn)行形態(tài)特征、生理生化特性和16S r DNA序列分析,確定其系統(tǒng)發(fā)育地位;通過(guò)單因素實(shí)驗(yàn)研究其最適降解條件;使用HPLC-MS分別對(duì)氟樂(lè)靈發(fā)酵液和降解菌株作用下的氟樂(lè)靈發(fā)酵液進(jìn)行化學(xué)組分進(jìn)行結(jié)構(gòu)分析,探究降解菌株對(duì)氟樂(lè)靈的降解途徑。主要研究結(jié)果如下:(1)以連作15年以上棉田土壤為材料,采用直接稀釋涂布法分離得到1株能夠降解氟樂(lè)靈的細(xì)菌D8,通過(guò)其形態(tài)特征、生理生化特性和16S rDNA同源性序列分析,鑒定菌株D8為蠟樣芽孢桿菌(Bacillus cereus)。(2)通過(guò)單因素實(shí)驗(yàn)測(cè)得菌株D8降解氟樂(lè)靈的最適底物濃度為50.00 mg/L、接種量為4.00%、外加氮源為濃度0.10%的酵母浸粉、溫度37℃、pH為5,在上述條件下培養(yǎng)3天時(shí)菌株對(duì)氟樂(lè)靈的降解率達(dá)59.89%以上。(3)利用安捷倫C-18反向色譜柱,柱溫為30℃,流動(dòng)相A相為純凈水,B相為甲醇,流速1 mL/min進(jìn)行全波長(zhǎng)掃描紫外檢測(cè)。在同一條件下,使用HPLC-MS分別對(duì)氟樂(lè)靈發(fā)酵液、蠟狀芽孢桿菌作用下的氟樂(lè)靈發(fā)酵液進(jìn)行化學(xué)組分分析及鑒定,發(fā)現(xiàn)蠟狀芽孢桿菌降解氟樂(lè)靈的可能降解途徑為氟樂(lè)靈脫烷基、脫氨基、硝基還原和環(huán)化反應(yīng),主要的降解產(chǎn)物有2-乙基-7-硝基-1-丙基-5-三氟甲基苯并咪唑、2-乙基-7-硝基-5-三氟甲基苯并咪唑和3-硝基-5-三氟甲基苯胺。
[Abstract]:Trifluridine is a widely used selective presprout herbicide with dinitroaniline which is mainly used in more than 40 crops and orchards such as sugar beet cotton tomato and so on. Annual grasses and some dicotyledonous weeds have been widely used in the world because of their broad spectrum, stable properties and effects, long duration of effect and so on. However, it has the characteristics of poor leaching solubility, it can be adsorbed by soil particles and accumulated in the surface soil layer, it is not easy to be washed away by Rain Water or leaching to the bottom of the soil, remaining in the soil. A small amount of trifluridine remained in the soil for up to two years and had an effect on the emergence rate and growth of crops. In this paper, the microbial degradation technology of fluryl residue pollution was studied, and the dilution separation culture method was used to screen the high-efficiency fluryl degrading bacteria. A strain with the best biodegradability was selected for morphological, physiological and biochemical analysis and 16s r DNA sequence analysis to determine its phylogenetic status. The optimum degradation conditions were studied by single factor experiment. HPLC-MS was used to analyze the chemical components of the fermenting broth and the broth under the action of the degrading strain respectively. The main results were as follows: 1) the soil of cotton field for more than 15 years was used as the material. A strain of bacteria D8 was isolated by direct dilution coating method and its morphological, physiological and biochemical characteristics and 16s rDNA homology were analyzed. The strain D8 was identified as Bacillus cereusus. The optimum substrate concentration of the strain D8 was 50.00 mg/L. The inoculation amount was 4. 00 and the concentration of nitrogen was 0.10%. The temperature was 37 鈩，

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