There is a critical need to develop innovative advanced organic contaminant treatment technologies that are effective, economical and environmentally sustainable. The presented work harnessed the high activity and versatility of fungal enzymes by developing novel surface display enzyme biocatalysts for treating emerging contaminants in water. Enzyme biocatalysis has high catalytic efficiency under ambient conditions of temperature and pressure. However, using enzymes in solution as additives for water treatment is not suitable and economical due to short enzyme lifetimes, non-reusability or renewability, and high cost of single use. Our study overcomes these challenges by immobilizing the fungal laccase or esterase on the outer surface of biological cells using synthetic biology methods, resulting in a new class of renewable biocatalysts. Successful surface display of the target enzymes was confirmed by microscope imaging and the enzyme activity assays. The surface display enzyme biocatalysts could retain significant activity (e.g. &gt;70% of initial activity) after eight rounds of operations and have high storage stability (e.g. 90% of initial activity after 30 days), while free enzymes showed lower stability and could not be reused. The created biocatalysts were applied to catalyze degradation of bisphenol A, sulfamethoxazole, acetaminophen, and phthalate esters. Results from contaminant degradation kinetics and the effects of redox mediator amendment provided insights into the factors affecting the efficacy of the surface display biocatalysts. The study demonstrated a new enzyme biocatalysis strategy that could potentially lead to an efficient, robust and renewable innovative advanced treatment alternative for treating persistent organic contaminants in water reclamation and reuse. Furthermore, the technology developed is highly modular: by changing the target enzymes for expression in the surface display platform system, renewable biocatalysts with different new functions of interest would be created and applied to address challenges relevant to other components at the food-water-energy nexus.

Surface display enzyme biocatalysts for treating emerging contaminants

255th National Meeting (2018)

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