细菌协同降解阴离子型聚丙烯酰胺的机理  

Synergistic Degradation Mechanism of Anionic Polyacrylamide by Bacteria

作　　者：王方略 张东晨[1] 吴学凤[2] 邓胜松 袁新宇 WANG Fanglue;ZHANG Dongchen;WU Xuefeng;DENG Shengsong;YUAN Xinyu(School of Material Science and Engineering,Anhui University of Science and Technology,Huainan 232001,China;School of Food and Bioengineering,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]安徽理工大学材料科学与工程学院,安徽淮南232001 [2]合肥工业大学食品与生物工程学院,安徽合肥230009

出　　处：《环境科学与技术》2022年第7期1-10,共10页Environmental Science & Technology

基　　金：国家自然科学基金(51274012)。

摘　　要：为了探究细菌混合协同降解阴离子型聚丙烯酰胺(HPAM)机理,作者以球红假单胞菌和枯草芽孢杆菌等体积混合构成混合菌,研究了单个菌株和混合菌的生长情况及降解特性。同时采用分子对接模拟了红球菌N-771酰胺酶(Rh Amidase)和枯草芽孢杆菌漆酶(Lac)与HPAM结构模型的结合。试验结果表明,枯草芽孢杆菌含有内生孢子,其适应环境的能力比球红假单胞菌强,而且2种菌株都含有鞭毛,运动剧烈。在温度35℃、pH 7、接种量2 mL和7 d的最佳条件下混合菌的降解率为39.24%,而球红假单胞菌和枯草芽孢杆菌的降解率分别为24.9%和22.13%。分子对接结果表明,Rh Amidase-HPAM-2亲和力最大、最稳定的主要原因是强氢键作用,而且它们的结合最佳。与Lac相比,Rh Amidase更容易攻击短链HPAM的酰胺侧链而引发水解。而Lac可以容纳一定长度的HPAM的碳链,倾向于氧化HPAM的碳链。根据试验结果与分子对接模拟的相互佐证,提出了细菌混合降解HPAM协同的机理,实质上是Rh Amidase和Lac共同催化降解HPAM。In order to explore the synergistic degradation mechanism of anionic polyacrylamide(HPAM)by mixed bacteria composed of Rhodobacter sphaeroides(R.sphaeroides)and Bacillus subtilis(B.subtilis)in equal volume,their growth and degradation characteristics were studied.Meanwhile,the binding of Rhodococcus sp.N-771 amidase(Rh Amidase)and B.subtilis laccase(Lac)with HPAM structure models were simulated by molecular docking.The experimental results showed that B.subtilis contained endospores were more adapt to the environment than R.sphaeroides,and both strains with flagella had vigorous movement.Under the optimal condition,such as 35℃,pH 7,inoculation amount of 2 mL and 7 d,the degradation rate of mixed bacteria was 39.24%,while the degradation rate of R.sphaeroides and B.subtilis were 24.9%and22.13%,respectively.Molecular docking results showed that Rh Amidase-HPAM-2 had the highest affinity and was the most stable,mainly due to the strong hydrogen bond.Moreover,their binding was the optimal.Compared with Lac,the amide side chain of short HPAM was easily ready to be attacked and hydrolyzed by Rh Amidase.But Lac could accommodate a certain length of HPAM carbon chain,and it tended to oxidize HPAM carbon chain.Based on the mutual support between experimental results and molecular docking simulation,the synergistic HPAM degradation mechanism by mixed bacteria was proposed.In essence,the degradation of HPAM was catalyzed jointly by Rh Amidase and Lac.

关 键 词：球红假单胞菌 枯草芽孢杆菌 漆酶 酰胺酶 阴离子型聚丙烯酰胺 

分 类 号：X172[环境科学与工程—环境科学]