BACKGROUND Bisphenol A is an important organic chemical as an intermediate, final and inert ingredient in manufacturing of many important products like polycarbonate plastics, epoxy resins, flame retardants, food-drink packaging coating, and other. BPA is an endocrine disruptor compound that mimics the function of estrogen causing damage to reproductive organs. Bacterial degradation has been consider as a cost effective and eco-friendly method for BPA degradation compared with physical and chemical methods. This study aimed to isolate and identify bacterial strain capable to degrade and tolerate high concentrations of this pollutant, studying the factors affecting the degradation process and study the degradation mechanism of this strain. RESULTS YC-AE1 is a Gram negative bacterial strain isolated from soil and identified as Pseudomonas putida by 16S rRNA gene sequence and BIOLOG identification system. This strain found to have a high capacity to degrade the endocrine disruptor Bisphenol A (BPA). Response surface methodology using central composite design was used to statistically optimize the environmental factors during BPA degradation and the results obtained by significant model were 7.2, 30 °C and 2.5% for optimum initial pH, temperature and inoculum size, respectively. Prolonged incubation period with low NaCl concentration improve the biodegradation of BPA. Analysis of variance (ANOVA) showed high coefficient of determination, R2 and Adj-R2 which were 0.9979 and 0.9935, respectively. Substrate analysis found that, strain YC-AE1 could degrade a wide variety of bisphenol A-related pollutants such as bisphenol B, bisphenol F, bisphenol S, Dibutyl phthalate, Diethylhexyl phthalate and Diethyl phthalate in varying proportion. Pseudomonas putida YC-AE1 showed high ability to degrade a wide range of BPA concentrations (0.5-1000 mg l- 1) with completely degradation for 500 mg l- 1 within 72 h. Metabolic intermediates detected in this study by HPLC-MS were identified as 4,4-dihydroxy-alpha-methylstilbene, p-hydroxybenzaldeyde, p-hydroxyacetophenone, 4-hydroxyphenylacetate, 4-hydroxyphenacyl alcohol, 2,2-bis(4-hydroxyphenyl)-1-propanol, 1,2-bis(4-hydroxyphenyl)-2-propanol and 2,2-bis(4-hydroxyphenyl) propanoate. CONCLUSIONS This study reports Pseudomonas putida YC-AE1 as BPA biodegrader with high performance in degradation and tolerance to high BPA concentration. It exhibited strong degradation capacity and prominent adaptability towards a wide range of environmental conditions. Moreover, it degrades BPA in a short time via two different degradation pathways.

中文翻译：

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从污染土壤中分离的恶臭假单胞菌菌株YC-AE1对内分泌干扰物双酚A的生物降解。

背景技术双酚A是重要的有机化学物质，是制造许多重要产品（如聚碳酸酯塑料，环氧树脂，阻燃剂，食品饮料包装涂料等）中的中间，最终和惰性成分。BPA是一种内分泌干扰物化合物，模仿雌激素的功能，导致生殖器官受损。与物理和化学方法相比，细菌降解已被认为是BPA降解的一种经济高效且环保的方法。这项研究旨在分离和鉴定能够降解和耐受高浓度这种污染物的细菌菌株，研究影响降解过程的因素并研究该菌株的降解机理。结果YC-AE1是革兰氏阴性菌，从土壤中分离得到，经16S rRNA基因序列和BIOLOG鉴定系统鉴定为恶臭假单胞菌。发现该菌株具有高降解内分泌干扰物双酚A（BPA）的能力。使用中央复合设计的响应面方法对BPA降解过程中的环境因素进行了统计学优化，对于最佳的初始pH，温度和接种量，通过显着模型获得的结果分别为7.2％，30°C和2.5％。低NaCl浓度下延长孵育时间可改善BPA的生物降解。方差分析（ANOVA）显示出较高的测定系数，R2和Adj-R2分别为0.9979和0.9935。底物分析发现，YC-AE1菌株可以降解各种与双酚A有关的污染物，例如双酚B，双酚F，双酚S，邻苯二甲酸二丁酯，邻苯二甲酸二乙基己酯和邻苯二甲酸二乙酯。恶臭假单胞菌YC-AE1显示出高的降解多种BPA浓度（0.5-1000 mg -1）的能力，并在72 h内完全降解500 mg -1。通过HPLC-MS在本研究中检测到的代谢中间体被鉴定为4,4-二羟基-α-甲基苯乙烯，对羟基苯甲酰胺，对羟基苯乙酮，4-羟基苯乙酸酯，4-羟基苯乙醇，2,2-双（4-羟基苯基） -1-丙醇，1，2-双（4-羟基苯基）-2-丙醇和2，2-双（4-羟基苯基）丙酸酯。结论本研究报告恶臭假单胞菌YC-AE1作为BPA生物降解剂，具有降解性能高，对高BPA浓度具有耐受性。它具有很强的降解能力，并且对各种环境条件都具有出色的适应性。此外，它可通过两种不同的降解途径在短时间内降解BPA。