Mr Krishnakumar SIVAKUMAR
PhD Student

Supervisors: Asst Prof. Cao Bin, Prof. Stefan Wuertz and Asst Prof. Yang Liang 

Project Title: Engineering biofilms for enhanced biofilm-based biocatalysis (electroconductivity, bioremediation)

Biocatalysis involve the conversion of a substrate into desired products by biological catalysts including a specific enzyme or whole cells resulting in biotransformations or bioremediation and other biochemical processes. Although the whole cell based approach fulfills the requirement of catalyst stability and robustness at all process conditions, it is largely limited to batch and fed-batch processes employing planktonic cells that has provided only limited information related to long term catalytic stability, retention, regeneration and the tolerance capacity to toxic reagents. Biofilms are the most ubiquitous and resilient form of microbial life on this planet enriched with diverse group of microorganisms embedded in an extracellular matrix and adhered to a specific surface and supported by diffusive transport of essential nutrients. The biofilm matrix imparts the mechanical stability and structural integrity as well as resistance against various physicochemical stresses, rendering such surface consortia attractive catalytic systems for biocatalysis. In spite of the advantages offered by biofilms certain bottlenecks have created a wide gap in broadly implementing the concept in biofilm based biocatalytic processes such as the diffusion limitation triggered by excessive production of EPS coupled with substantial amount of biomass accumulated within a biofilm that not only arrest the mass transfer and fluid flow but also increases the diffusion distances causing detrimental effects to the biofilm robustness. To alleviate mass transfer issues in biofilm-based biocatalysis, this project focuses on the development of robust and efficient biofilm-based biocatalytic systems through matrix engineering to make the biofilm matrix a “micro factory” for chemical synthesis. Specifically, we propose two approaches: i) use of membrane-spanning conjugated oligoelectrolytes to enhance extracellular biocatalysis; and ii) genetically engineering biofilm matrix to exhibit extracellular biocatalytic activities.