Propylene glycol (PG), commonly used in the food, cosmetics and pharmaceutical industries and considered non-PBT, is still an emerging contaminant of concern due to its widespread use. In this study, an isolate of a bacterial consortium obtained from an effluent treatment plant, MC1S, was used to degrade PG. The growth kinetics of the isolate was studied under aerated and non-aerated conditions. The isolate was able to effectively grow in saline water under aerated conditions using PG as the substrate. Using response surface methodology (RSM), the effect of pH, salinity, PG concentration, phosphate and nitrate concentration on cell growth and PG degradation was investigated. The isolated bacterium, MC1S, was capable of degrading PG with a maximum of 79% COD reduction observed and was able to withstand comparatively high salinity of the medium. Solution pH and salinity were the most important parameters affecting degradation. Salinity less than 0.1 M and pH close to 8 appeared to be the optimum conditions for PG degradation. HPLC analysis of the treated sample appeared to show the presence of three daughter products. Using RSM, a quadratic equation model between COD reduction and the process variables was developed. The results indicated that aerobic treatment of PG under specific conditions was the best approach for the specific isolate.

中文翻译：

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从城市污水处理污泥中分离菌群对丙二醇废水进行生物降解-工艺动力学及优化

通常在食品，化妆品和制药行业中使用的丙二醇（PG）被认为是非PBT的，由于其广泛使用，它仍然是令人关注的新兴污染物。在这项研究中，从污水处理厂MC1S获得的细菌菌群的分离物用于降解PG。在充气和非充气条件下研究了分离株的生长动力学。使用PG作为底物，分离物能够在充气条件下的盐水中有效生长。使用响应表面方法（RSM），研究了pH，盐度，PG浓度，磷酸盐和硝酸盐浓度对细胞生长和PG降解的影响。分离的细菌，MC1S能够降解PG，最大观察到COD降低79％，并且能够承受较高盐度的培养基。溶液的pH和盐度是影响降解的最重要参数。盐度小于0.1 M且pH值接近8似乎是PG降解的最佳条件。经处理的样品的HPLC分析似乎表明存在三种子产物。使用RSM，建立了COD减少与过程变量之间的二次方程模型。结果表明，在特定条件下对PG进行好氧处理是分离特定菌株的最佳方法。