Polymer selection for biphenyl degradation in a solid-liquid two-phase partitioning bioreactor.

Area of Science:

• Biotechnology and Bioremediation
• Environmental Engineering
• Polymer Science

Background:

• Hydrophobic compounds like biphenyl pose challenges in biodegradation due to poor water solubility.
• Two-phase partitioning bioreactors (TPPB) offer a solution by immobilizing substrates in a separate phase.
• Previous TPPBs often used liquid-liquid systems, limiting biocatalyst options.

Purpose of the Study:

• To develop a rational strategy for selecting solid polymeric materials for biphenyl delivery in TPPBs.
• To evaluate the efficiency of biphenyl degradation using a solid-phase TPPB.
• To demonstrate the expanded applicability of TPPBs with solid delivery phases.

Main Methods:

• Thermoplastic polymers, including Hytrel, Nylon 6.6, and Desmopan, were investigated as solid delivery phases.
• Biphenyl partitioning coefficients between polymers and water were determined.
• Degradation of biphenyl was assessed using Burkholderia xenovorans LB400 and a soil-derived microbial consortium in TPPBs.

Main Results:

• Hytrel was successfully used as a delivery phase for biphenyl degradation.
• Significant biphenyl degradation (2.9 g) was achieved within 45-50 hours in 1-L TPPBs.
• Partitioning coefficients varied widely, with Desmopan showing a high value (11,000), comparable to organic solvents.

Conclusions:

• Solid polymeric delivery phases provide an effective strategy for immobilizing and degrading poorly soluble compounds like biphenyl.
• The use of solid phases enables the application of surfactant-producing microbial cultures, broadening TPPB utility.
• This approach enhances the range of biocatalysts applicable in TPPBs for bioremediation.