發(fā)布時(shí)間：2018-05-24 06:01

  本文選題：狐尾藻 + 伊樂藻　； 參考：《華中師范大學(xué)》2015年碩士論文

【摘要】：雙酚A(BisphenolA,簡(jiǎn)稱BPA),作為一種典型的環(huán)境內(nèi)分泌干擾物,廣泛應(yīng)用于化工行業(yè),在生產(chǎn)和使用過程中通過廢水或廢物進(jìn)入水環(huán)境,造成各種水體的污染,對(duì)水生態(tài)系統(tǒng)的健康穩(wěn)定構(gòu)成了潛在威脅。狐尾藻(Myriophyllum verticillatum)和伊樂藻(Elodeacanadensis)作為沉水植物的重要代表,能夠凈化水體,是水體污染修復(fù)的先鋒植物。同時(shí),廣泛分布在植物體內(nèi)的內(nèi)生菌不僅能促進(jìn)植物生長(zhǎng),而且可以增強(qiáng)植物體對(duì)環(huán)境污染物的降解,減輕污染物對(duì)植物體的毒害。因此,以狐尾藻和伊樂藻為實(shí)驗(yàn)材料,開展降解BPA內(nèi)生菌的篩選鑒定、降解特性和降解機(jī)理的相關(guān)研究,有助于了解水生生態(tài)系統(tǒng)中BPA的歸趨,闡明沉水植物降解BPA的內(nèi)在機(jī)制,對(duì)污染水體中BPA的生物修復(fù)有指導(dǎo)作用。本文首次從沉水植物內(nèi)生菌中分離到了降解BPA的新型菌株,并對(duì)高效菌株的降解特性、降解機(jī)理等進(jìn)行探索,為環(huán)境中BPA的歸趨研究及水體BPA的污染治理奠定理論基礎(chǔ)。研究結(jié)果如下:(1)從沉水植物狐尾藻中分離篩選到了降解環(huán)境內(nèi)分泌干擾物雙酚A的內(nèi)生細(xì)菌Mv32。通過搖瓶實(shí)驗(yàn)進(jìn)行了菌株降解條件的優(yōu)化和降解特性的探索,發(fā)現(xiàn)當(dāng)BPA初始濃度為10 mg/L時(shí),菌株Mv32的最佳降解條件為接種量1%,初始pH值7,溫度25℃,在該條件下,菌株最大生長(zhǎng)濃度OD600達(dá)到0.22,3d對(duì)10mg/L BPA的降解率達(dá)到47.17 ± 1.22%。經(jīng)過對(duì)其形態(tài)特征和16S rRNA基因同源性序列分析,鑒定菌株Mv32為類芽孢桿菌屬(Paenibacillussp.)。投加菌株Mv32(OD600=1.0,1%),對(duì)于南湖水樣中BPA(10 mg/L)3d的去除率為95.78 ±0.31%。(2)從沉水植物伊樂藻中分離篩選到了降解雙酚A的內(nèi)生細(xì)菌Ec18,并進(jìn)行了菌株降解條件的優(yōu)化和降解特性的探索,發(fā)現(xiàn)當(dāng)BPA初始濃度為10 mg/L時(shí),菌株Ec18的最佳降解條件為接種量2%,初始pH值6,溫度30℃,在該條件下,菌株最大生長(zhǎng)濃度OD600達(dá)到0.23,3 d對(duì)10 mg/L BPA的降解率達(dá)到40.59 ±0.60%。經(jīng)過對(duì)其形態(tài)特征和16S rRNA基因同源性序列分析,鑒定菌株Ec18為甲基桿菌屬(Methylobacterium sp.)。菌株Ec18(OD600=1.0,1%)對(duì)投加于南湖水樣中的 BPA(10 mg/L)3 d 的去除率為 68.47 ± 1.91%。(3)通過添加特異性酶抑制劑對(duì)降解菌株去除BPA影響的實(shí)驗(yàn),探索可能參與BPA降解的酶。結(jié)果表明,P450酶抑制劑和漆酶抑制劑能夠顯著抑制菌株對(duì)BPA的降解,推測(cè)P450酶和漆酶參與了 BPA的生物轉(zhuǎn)化過程。此外,利用簡(jiǎn)并引物CulAF和Cu2R擴(kuò)增得到漆酶的部分序列,經(jīng)過對(duì)擴(kuò)增序列的分析,發(fā)現(xiàn)該序列與已報(bào)道漆酶氨基酸序列的覆蓋率為97%,相似性高達(dá)79%,推測(cè)該序列為新型細(xì)菌漆酶基因。
[Abstract]:Bisphenol A BisphenolA (BPAA), as a typical environmental endocrine disruptor, is widely used in chemical industry. It enters the water environment through waste water or waste in the process of production and use, resulting in the pollution of various water bodies. It poses a potential threat to the health and stability of the aquatic ecosystem. Myriophyllum verticillatum and Elodea adenensis are important representatives of submerged plants, which can purify the water body and are the pioneer plants in the remediation of water pollution. At the same time, endophytic bacteria widely distributed in plants can not only promote the growth of plants, but also enhance the degradation of environmental pollutants and reduce the toxicity of pollutants to plants. Therefore, the screening and identification of endophytic bacteria for degradation of BPA and the study on degradation characteristics and degradation mechanism of BPA in aquatic ecosystem are helpful to understand the fate of BPA in aquatic ecosystem. The mechanism of degradation of BPA by submerged plants is elucidated, which can guide the bioremediation of BPA in polluted water. In this paper, a new strain for degradation of BPA was first isolated from endophytic bacteria of submerged plants. The degradation characteristics and degradation mechanism of high efficient strains were explored, which laid a theoretical foundation for the study of the fate of BPA in the environment and the pollution control of BPA in water. The results are as follows: (1) the endophytic bacteria Mv32which degrades the environmental endocrine disruptor bisphenol A was isolated and screened from the submerged plant Foxtail. The strain degradation conditions were optimized and the degradation characteristics were explored by shaking flask experiment. It was found that when the initial concentration of BPA was 10 mg/L, the optimal degradation conditions of strain Mv32 were inoculation amount 1, initial pH value 7, temperature 25 鈩，

本文編號(hào)：1927951