Department of Chemical Engineering and Environmental Technology, Valladolid University, Paseo del Prado de la Magdalena, s/n, 47011 Valladolid, Spain.
Biotechnol Bioeng. 2010 Aug 1;106(5):731-40. doi: 10.1002/bit.22748.
A comparative study of the performance of solid and liquid non-aqueous phases (NAPs) to enhance the mass transfer and biodegradation of hexane by Pseudomonas aeruginosa in two-phase partitioning bioreactors (TPPBs) was undertaken. A preliminary NAP screening was thus carried out among the most common solid and liquid NAPs used in pollutant biodegradation. The polymer Kraton G1657 (solid) and the liquid silicone oils SO20 and SO200 were selected from this screening based on their biocompatibility, resistance to microbial attack, non-volatility and high affinity for hexane (low partition coefficient: K = C(g)/C(NAP), where C(g) and C(NAP) represent the pollutant concentration in the gas phase and NAP, respectively). Despite the three NAPs exhibited a similar affinity for hexane (K approximately 0.0058), SO200 and SO20 showed a superior performance to Kraton G1657 in terms of hexane mass transfer and biodegradation enhancement. The enhanced performance of SO200 and SO20 could be explained by both the low interfacial area of this solid polymer (as a result of the large size of commercial beads) and by the interference of water on hexane transfer (observed in this work). When Kraton G1657 (20%) was tested in a TPPB inoculated with P. aeruginosa, steady state elimination capacities (ECs) of 5.6 +/- 0.6 g m(-3) h(-1) were achieved. These values were similar to those obtained in the absence of a NAP but lower compared to the ECs recorded in the presence of 20% of SO200 (10.6 +/- 0.9 g m(-3) h(-1)). Finally, this study showed that the enhancement in the transfer of hexane supported by SO200 was attenuated by limitations in microbial activity, as shown by the fact that the ECs in biotic systems were far lower than the maximum hexane transfer capacity recorded under abiotic conditions.
一项比较研究了固相和液相非水相（NAPs）在两相分配生物反应器（TPPB）中增强铜绿假单胞菌对己烷的传质和生物降解的性能。因此，在污染物生物降解中最常用的固相和液相 NAP 中进行了初步的 NAP 筛选。从该筛选中选择了聚合物 Kraton G1657（固相）和液体硅油 SO20 和 SO200，基于它们的生物相容性、抗微生物攻击性、非挥发性和对己烷的高亲和力（低分配系数：K = C(g)/C(NAP)，其中 C(g) 和 C(NAP) 分别表示气相和 NAP 中的污染物浓度）。尽管这三种 NAP 对己烷的亲和力相似（K 约为 0.0058），但 SO200 和 SO20 在增强己烷传质和生物降解方面的性能优于 Kraton G1657。SO200 和 SO20 的增强性能可以通过这种固体聚合物的低界面面积（由于商业珠粒的尺寸较大）以及水对己烷传递的干扰（在本工作中观察到）来解释。当在接种铜绿假单胞菌的 TPPB 中测试 Kraton G1657（20%）时，达到了 5.6 +/- 0.6 g m(-3) h(-1)的稳态去除容量（ECs）。这些值与没有 NAP 时获得的值相似，但低于在存在 20% SO200 时记录的 ECs（10.6 +/- 0.9 g m(-3) h(-1)）。最后，这项研究表明，SO200 支持的己烷传递增强被微生物活性的限制所减弱，事实是生物系统中的 ECs远低于非生物条件下记录的最大己烷传递容量。
