發(fā)布時間：2018-05-17 09:00

  本文選題：殺草丹 + 生物降解��； 參考：《南京農(nóng)業(yè)大學(xué)》2015年碩士論文

【摘要】：從殺草丹生產(chǎn)藥廠排污口所得土樣中分離到一株能以殺草丹為唯一碳源生長的細(xì)菌S351(16S rDNA GenBank登陸號:KR048280)。根據(jù)其生理生化和16S rDNA序列序列相似度分析,將該菌鑒定為食酸菌屬(Acidowrax sp.)。菌株屬G-菌,菌落為白色,不透明,黏度較大,圓形,邊緣齊整,凸起。較濕潤,不容易挑取;菌體呈短桿狀,表面多皺褶,有莢膜,沒有觀察到鞭毛,不產(chǎn)芽孢。對菌株S351的生物學(xué)特性研究結(jié)果顯示,該菌株在pH6.0～7.0范圍內(nèi)生長良好,在pH7.0生長最好,最適生長溫度為30℃,裝液量20mL時,生長量最大,隨著裝液量的增加生長呈下降趨勢。在0～10mg·L-1的鹽濃度范圍生長較好,以葡萄糖,果糖為碳源的培養(yǎng)基中生長較好。該菌株在36h內(nèi)對100mgL-1的殺草丹降解率達(dá)到99.6%。降解殺草丹的最適溫度為30℃,pH值為7.0,降解速率與初始接種量呈正相關(guān)。接種量大于5%時有較高降解效果。通過降解菌株S351利用底物的情況,發(fā)現(xiàn)能利用對氯芐硫醇,對氯苯甲酸和對羥基苯甲酸等,但不能利用氯苯,2,4,6-三氯苯和芐硫醇。將該菌株在不加殺草丹的無選擇壓力平板上連續(xù)劃線傳代后,獲得一株降解功能丟失的突變株S3512,對野生株S351和突變株S3512進(jìn)行了全基因組測序,獲得了兩個菌株的基因組框架圖。根據(jù)全基因組框架圖的基因注釋和下載的fcbABC基因的保守區(qū)設(shè)計引物,從殺草丹降解菌株S351擴增到了對氯苯甲酸的降解基因。對菌株S351對殺草丹的降解途徑進(jìn)行了比較詳細(xì)的推測,根據(jù)實驗結(jié)果,以及基因組的測序結(jié)果,確定了一條殺草丹的完整代謝途徑。對菌株S351和突變株S3512的基因組框架圖比對,發(fā)現(xiàn)了突變株的多個疑似缺失片段,經(jīng)過PCR驗證,確定了兩個片段,contig180和contig138,用設(shè)計引物PCR推斷的方法,確定了兩個片段的連接方式是contig180-contig138,對這個拼接片段進(jìn)行側(cè)翼片段擴增,將獲得的片段和已知片段拼接,獲得了不一條長約9k的片段,其中,一端已經(jīng)確定,另一端有待繼續(xù)研究。對殺草丹降解酶的粗酶液進(jìn)行了初步研究,沒有檢測到明顯酶活,可能是由于卻某種輔酶(輔因子)。
[Abstract]:A strain of bacteria S351N 16s rDNA GenBank was isolated from the soil sample from the sewage outlet of Shicaodan production Factory, which can grow with the sole carbon source. The landing number is: KR048280. According to the similarity analysis of physiological and biochemical characteristics and 16s rDNA sequence, the strain was identified as Acidowrax sp. The colony is white, opaque, sticky, round, well-edged and protruding. The bacteria were short rod shaped, pleated surface, had capsule, no flagella was observed, and no spores were produced. The biological characteristics of strain S351 showed that the strain grew well in the range of pH6.0~7.0, and grew best in pH7.0. The optimum growth temperature was 30 鈩，

本文編號：1900764