Prpich George P, Daugulis Andrew J
Department of Chemical Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada.
Biotechnol Prog. 2004 Nov-Dec;20(6):1725-32. doi: 10.1021/bp049921u.
Two-Phase Partitioning Bioreactors (TPPBs) have traditionally been used to partition toxic concentrations of xenobiotics from a cell-containing aqueous phase by means of an immiscible organic solvent and to deliver these substrates back to the cells on the basis of metabolic demand and the maintenance of thermodynamic equilibrium between the phases. A limitation of TPPBs, which use organic liquid solvents, is the possibility that the solvent can be bioavailable, and this has therefore limited organic liquid TPPBs to the use of pure strains of microbes. Solid polymer beads have recently been introduced as a replacement for liquid organic solvents, offering similar absorption properties but with the capability to be used with mixed microbial populations. The present work was aimed at identifying a polymer with a greater capacity for and more rapid uptake and release of phenol for use as the second phase in a mixed culture TPPB. Polarity and hydrogen bonding capabilities between polymer and phenol were considered in the screening and selection process of candidate polymers. Hytrel (a copolymer of poly(butylene terephthalate) and butylene ether glycol terephthalate) polymer beads, offered improved capacity (19 mg phenol/g polymer at a fixed initial phenol concentration of 2000 mg/L) and a greater diffusivity (1.54 x 10(-7) cm2/s) when compared to the capacity and diffusivity of previously used EVA (ethylene vinyl acetate) beads (12.4 mg phenol/g polymer and 3.73 x 10(-9) cm2/s, respectively). Hytrel polymer beads were then used in a TPPB for the investigation of various substrate feeding strategies (fed-batch, bead replacement, and concentrated spikes of phenol), with rapid and complete phenol degradation shown in all cases.
两相分配生物反应器（TPPB）传统上用于通过不混溶的有机溶剂将有毒浓度的异生素从含细胞水相中分离出来，并根据代谢需求和两相之间热力学平衡的维持将这些底物输送回细胞。使用有机液体溶剂的TPPB的一个局限性是溶剂可能具有生物可利用性，因此这限制了有机液体TPPB仅能使用纯微生物菌株。最近引入了固体聚合物珠来替代液体有机溶剂，其具有相似的吸收特性，但能够与混合微生物群体一起使用。本研究旨在确定一种对苯酚具有更大容量、更快吸收和释放能力的聚合物，用作混合培养TPPB中的第二相。在候选聚合物的筛选和选择过程中考虑了聚合物与苯酚之间的极性和氢键能力。与先前使用的EVA（乙烯-醋酸乙烯酯）珠（分别为12.4 mg苯酚/g聚合物和3.73×10⁻⁹ cm²/s）的容量和扩散率相比，Hytrel（聚对苯二甲酸丁二醇酯和对苯二甲酸丁二醇醚共聚物）聚合物珠具有更高的容量（在固定初始苯酚浓度为2000 mg/L时为19 mg苯酚/g聚合物）和更大的扩散率（1.54×10⁻⁷ cm²/s）。然后将Hytrel聚合物珠用于TPPB中，以研究各种底物进料策略（分批补料、珠替换和苯酚浓缩加样），所有情况下均显示苯酚能快速且完全降解。
