Water Research Institute, CNR, Monterotondo Scalo (Rome), Italy.
J Hazard Mater. 2011 Jul 15;191(1-3):190-5. doi: 10.1016/j.jhazmat.2011.04.061. Epub 2011 Apr 21.
The biological treatment of phenolics is constrained by the inherent cytotoxicity of these compounds. One method to alleviate such toxicity is to add a sequestering phase to absorb, and subsequently release, the substrate(s) to the micro-organisms; such a system is termed a Two Phase Partitioning Bioreactor. Here we have compared the performance of a TPPB, relative to single phase operation, in which a small volume (5%, v/v) of beads of the polymer Hytrel 8206 was used to treat aqueous mixtures of 2,4-dimethylphenol and 4-nitrophenol. Hytrel 8206 was selected from a range of polymers that were tested for their partition coefficients (PCs) for the target molecules, with the more hydrophobic compound (2,4-dimethylphenol) having a higher PC value (201) than 4-nitrophenol (143). Significantly increased removal rates for both substrates were demonstrated in TPPB mode relative to single phase operation. Additionally, the differential release of the compounds to the aqueous phase and their distinct PC values changed the kinetic pattern of the biotreatment system, smoothing out the cellular oxygen demand. Release of the substrates by the polymer over 60 operating cycles was virtually complete (>97%) demonstrating the reusability and robustness of the use of polymers in overcoming cytotoxicity of phenolic substrates.
酚类的生物处理受到这些化合物固有细胞毒性的限制。一种减轻这种毒性的方法是添加一种隔离相来吸收，并随后将底物释放给微生物；这种系统被称为两相分配生物反应器。在这里，我们比较了两相分配生物反应器（TPPB）与单相操作的性能，其中使用了小体积（5%，v/v）的聚合物 Hytrel 8206 珠来处理 2,4-二甲基苯酚和 4-硝基苯酚的水溶液混合物。Hytrel 8206 是从一系列聚合物中选择的，这些聚合物的分配系数（PC）是针对目标分子进行测试的，疏水性更高的化合物（2,4-二甲基苯酚）的 PC 值（201）高于 4-硝基苯酚（143）。与单相操作相比，TPPB 模式下两种基质的去除率均显著提高。此外，化合物向水相的差异释放及其不同的 PC 值改变了生物处理系统的动力学模式，使细胞耗氧量趋于平稳。聚合物在 60 多个操作循环中几乎完全释放（>97%），证明了聚合物在克服酚类基质细胞毒性方面的可重复使用性和稳健性。
