深海真菌对邻苯二甲酸酯的降解特性研究

发布时间：2018-05-03 12:40

本文选题：深海真菌 + 邻苯二甲酸酯　；参考：《福建农林大学》2015年硕士论文

【摘要】：邻苯二甲酸二甲酯类(DMPEs),属于邻苯二甲酸酯类(PAEs),是一种广泛应用于工业和日常生活中的难降解有机物。PAEs主要用作增塑剂和添加剂,被广泛用于食品包装、儿童玩具、家具、甚至化妆品等行业,已然成为环境中一种无处不在的污染物。本文首次利用从水深2948 m的大西洋深海沉积物中分离出的一株DMPEs降解真菌Mar-Y3和从水深3300 m的印度洋深海沉积物中分离出一株DMPEs降解真菌IR-M4,并通过形态学观察和ITS rDNA基因序列比对分析,分别鉴定为胶红酵母(Rhodotorula mucilaginosa Mar-Y3)和杂色曲霉(Aspergillus versicolor IR-M4),并其部分ITS序列存入GenBank数据库,登录号分别为KM052362、KM052361。进而分析这两株深海真菌对PAEs中九种底物((邻苯二甲酸二甲酯(DMP)、间苯二甲酸二甲酯(DMI)、对苯二甲酸二甲酯(DMT)、邻苯二甲酸单甲酯(MMP)、间苯二甲酸单甲酯(MMI)、对苯二甲酸单甲酯(MMT)、邻苯二甲酸(PA)、间苯二甲酸(IA)和对苯二甲酸(TA))的降解情况,并确定出两株真菌对DMPEs三种同分异构体的生物降解途径,探讨其降解机制。对于深海酵母菌株R. mucilaginosa Mar-Y3,结果显示此深海酵母能够利用DMPEs不同同分异构体作为唯一碳源和能源,将其完全转化为相应的苯二甲酸单甲酯和苯二甲酸,但其降解途径差异较大：对DMP和DMI只能进行一步的酯水解,将其降解为相应的单酯(分别为MMP和MMI),无法进一步降解这两个单酯；DMT能快速被此酵母产生的二酯酶转化MMT,随后进一步水解为TA,再无法对其进一步降解。本研究显示R. mucilaginosa Mar-Y3通过不同的催化过程参与DMPEs的降解并对不同底物具有不同的降解途径和降解速率,表明其降解DMPEs的两个酯键的酯酶具有高度的底物特异性。对于深海曲霉菌株A. versicolor IR-M4,结果显示此深海曲霉并不能利用DMP作为唯一碳源和能源并降解DMP,仅能利用DMI和DMT作为唯一碳源和能源,将其完全转化为相应的邻苯二甲酸单甲酯和邻苯二甲酸,但其降解途径也不经相同：深海曲霉能快速将DMI转化为间苯二甲酸单甲酯MMI,却无法进一步降解MMI；而DMT能被该菌株转化MMT,随后能进一步被水解为TA。本研究显示深海曲霉菌株A. versicolor IR-M4通过不同的催化过程参与DMPEs的降解并对不同底物具有不同的降解途径和降解速率,表明其降解DMPEs的两个酯键的酯酶具有高度的底物特异性。由于实验结果表明两株深海真菌均不能降解PA、IA和TA,为了能彻底降解PAEs及双加氧酶的研究,故另从两个海拔5000 m以下的深海沉积物样品中筛选出13株邻苯二甲酸类(PA、IA、TA)降解真菌。经分离鉴定,发现其中镰刀属Fusarium为优势菌株,其次为帚枝霉属Sarocladium,红酵母Rhodotorula和曲霉Aspergillus分布较少。本研究首次报道了利用从深海沉积物中分离的红酵母和曲霉,并以DMPEs作为唯一碳源和能源完成其降解过程,表明深海沉积物真菌在DMPEs污染海洋环境的生物修复中具有非常巨大的潜在应用价值。
[Abstract]:Phthalic acid two formic acid two methyl ester (DMPEs), belonging to the phthalic acid two formic acid ester (PAEs), is a kind of refractory organic substance, which is widely used in industry and daily life,.PAEs is mainly used as plasticizer and additive. It is widely used in food packaging, children's toys, furniture, even cosmetic products, and has become a ubiquitous pollution in the environment. For the first time, a strain of DMPEs degrading fungus Mar-Y3 isolated from the deep sea sediments of 2948 m deep water in the Atlantic and a DMPEs degrading fungus IR-M4 from the deep sea sediments of the India Ocean from the depth of 3300 m were isolated and identified as Rhodotorula mucil by morphological observation and sequence alignment of ITS rDNA gene. Aginosa Mar-Y3) and Aspergillus niger (Aspergillus versicolor IR-M4), and their partial ITS sequences deposited in the GenBank database, the login number is KM052362, and KM052361. further analyses 9 substrates of these two deep-sea fungi (two methyl phthalate (DMP), two methyl ester (DMI), two methyl terephthalate, and o-benzene two). The degradation of monomethyl formate (MMP), monomethyl ester (MMI), monomethate terephthalate (MMT), phthalic acid (PA), phthalic acid two formic acid (IA) and terephthalic acid (TA)), and determine the biodegradation pathway of two fungi to three isomers of DMPEs and explore the degradation mechanism of the deep-sea yeast strain R. mucilaginosa Mar. -Y3, the results show that this deep-sea yeast can make use of different isomers of DMPEs as the only carbon source and energy, and completely convert it into the corresponding monomethyl benzoate and benzoic acid two formic acid, but the degradation pathway is different: DMP and DMI can only be hydrolyzed by one step, and they can be degraded to the corresponding monoesters (MMP and MMI respectively). Further degradation of the two monoesters; DMT can be quickly converted to MMT by the yeast produced by this yeast, and then further hydrolyzed to TA, which can not be further degraded. This study shows that R. mucilaginosa Mar-Y3 participates in the degradation of DMPEs by different catalytic processes and has different degradation pathways and degradation rates for different substrates, indicating that the mucilaginosa Mar-Y3 has different degradation pathways and degradation rates. The esterase, which degrade two ester bonds of DMPEs, has a high substrate specificity. For the deep sea Aspergillus strain A. versicolor IR-M4, the results show that this deep-sea Aspergillus can not use DMP as the only carbon source and energy and degrade DMP. It can only use DMI and DMT as the only carbon source and energy, and completely transform it into the corresponding phthalic acid monomethyl ester. And phthalic acid two formic acid, but its degradation pathway is not the same: deep sea Aspergillus can quickly transform DMI into MMI, but can not further degrade MMI, and DMT can be converted to MMT by the strain, and then can be further hydrolyzed to TA.. The study shows that A. versicolor IR-M4 in deep-sea Aspergillus strain is involved in D through different catalytic processes. The degradation of MPEs and the different degradation pathways and rates of different substrates showed that the two ester bonds of the DMPEs were highly substrate specific. The experimental results showed that two strains of deep-sea fungi were unable to degrade PA, IA and TA, in order to degrade PAEs and the study of double oxygenase thoroughly, thus from two elevation of 5000 m. 13 phthalic acid (PA, IA, TA) degrading fungi were screened in the deep-sea sediment samples. After isolation and identification, it was found that sickle genus Fusarium was the dominant strain, followed by Sarocladium, Rhodotorula and Aspergillus Aspergillus, and the red leaven separated from deep sea sediments was reported for the first time. Mother and Aspergillus, and use DMPEs as the only carbon source and energy to complete its degradation process, show that deep-sea sediment fungi have great potential application value in bioremediation of DMPEs polluted marine environment.

【学位授予单位】：福建农林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X172

【相似文献】