| A solid-liquid two-phase partitioning bioreactor (TPPB) has been designed for the enhanced biotransformation of organic molecules. Traditional TPPBs consist of an aqueous, cell containing phase and a biocompatible, immiscible organic liquid that partitions toxic molecules, while maintaining thermodynamic equilibrium. Such systems may encounter limitations such as solvent biocompatibility, formation of emulsions and the requirement of using pure species of organisms. These issues have been addressed through the replacement of immiscible liquids with solid, inert polymer matrices that absorb and release small organic molecules in an analogous fashion to that of organic solvents. Two model biotransformations were chosen to illustrate the capabilities of a solid-liquid TPPB with the first investigating the biodegradation of a toxic substrate (phenol) and the second examining the bioproduction of a toxic product (3-methylcatechol).; Phenols were chosen as model contaminants for the investigation of the biodegradative potential of a solid-liquid TPPB and the inert polymer matrix enabled the utilization of mixed microbial populations that enhanced the rate of phenol biodegradation by 34% compared to a system using a single microbial isolate. Rational polymer selection was used to identify HYTREL(TM), a thermoplastic with hydrogen bonding potential, as possessing a high affinity for phenol. The versatility of this system was illustrated via the biodegradation of phenolic mixtures as well as the bioremediation of phenol-contaminated soil.; The bioconversion of toluene to 3-methylcatehcol via Pseudomonas putida MC2 was chosen as a model biotransformation examining the capability of a solid-liquid TPPB for the in situ recovery of a toxic product. An initial 'best-case' benchmark liquid-liquid TPPB was first developed for comparison purposes, and operation of the liquid-liquid system, achieved a volumetric productivity of 213 mg 3MC/L-h. A solid-liquid system, employing HYTREL(TM) as the polymeric phase, enhanced productivity by 60% over this benchmark. Alternative modes of solid-liquid operation were shown to increase productivity and they included the use of bioreactor internals constructed of HYTREL(TM) as well as a continuous system employing external extraction columns packed with HYTREL(TM).; This work has demonstrated that immiscible organic solvents may be successfully replaced with polymers and in doing so were shown to enhance the performance of both a biodegradative and biosynthetic process.; Keywords. phenols, 3-metliylcatechol, biodegradation, biocatalysis, solid-liquid two phase partitioning bioreactor, polymer... |
