Staff Profile - Newcastle University in Singapore

Assistant Professor, Degree Program Director Chemical Engineering (UG), Degree Program Director Process Safety and Risk Management (PG)

Background

Qualifications

PhD, University of Cambridge

BEng (Honours 1), Queen’s University of Belfast

Awards

• Visiting Scientist
• Fellow of the Cambridge Commonwealth Society
• Recipient of sponsorship from the Cambridge Commonwealth Trust
• Richardson's Fertiliser Medal and Prize
• IChemE (NI) Prize

Memberships

• Professional Engineer, Professional Engineers Board, Singapore
• Chartered Engineer, Member of the Institution of Chemical Engineers
• Chartered Engineer, Member of the Institution of Engineers Singapore
• Member of the Society of Biology

Research

Research Profile

Stem cells and regenerative medicine

Stem cells and tissue engineering is an exciting area of research where the ability of stem cells or derived cellular products offer to replace cells that are damaged, lost or malfunctioned in regenerative medicine. Stem cells with their proliferative capacities and their pluripotency or multipotency, are able to multiply in culture in-vitro, and to differentiate into any cell type given the right signalling. These cells when expanded and processed in large numbers can be used for transplantation and cell therapy. The major challenge is the ability to induce stem cell proliferation and differentiation to produce the targeted cell type at the required quantity for regenerative medicine.

We have cultured neural stem cells as three-dimensional aggregates in a number of configurations of bioreactors. The design and configuration of the bioreactor were shown to be crucial factors for the successful propagation and separation of the cells. We have also investigated and found the importance of cell-to-cell adhesion and adhesion to extracellular matrices in directing stem cell proliferation and differentiation. We have expertise in the proliferation and differentiation of mesenchymal stem cells into bone and other tissues. As mesenchymal stem cells can be used in autologous transplantation, it provides great potential in cell therapy and regenerative medicine.

In-situ product recovery as a bio separation strategy to improve bio production

Product inhibition often limits bio production, dictating the maximum concentration of product attainable in the fermentation broth. Escherichia coli transformed with the hpd BCA operon was shown to express p-hydroxyphenylacetate decarboxylase, converting p-hydroxyphenylacetate to p-cresol under anaerobic fermentation. Toxicity of p-cresol found at a concentration as low as 5 mM was shown to have limited the maximum concentration of p-cresol in the broth. Product yield was however shown to increase by 51% when in-situ product recovery was used to remove p-cresol as it was produced in batch fermentation. 

Pollution abatement technologies

Hydrogen sulphide is one of the major toxic sulphur compounds present in the odorous emission from Municipal Wastewater Treatment Plants and has an odor threshold of as low as 100 ppm. Due to the nuisance caused by the odor, a peripheral distance has to be kept around Wastewater Treatment Plants in order to allow for the dilution of the odor without affecting the community. This can be very costly especially in countries where there is a high demand on land-use. Alternatively, the Wastewater Treatment Plants can be covered and the odorous air extracted and treated before being discharged into the atmosphere. We have worked with the use of various kinds of activated carbon and activated carbon immobilized with a bacteria enriched from activated sludge to remove the odorous compounds before discharge to the atmosphere.

Mercury vapor emitted from combustion processes can give rise to a pollution of toxic heavy metal in the atmosphere. A project was undertaken to study the adsorption and reaction of mercury vapor emission from incineration and coal-fired energy plants using activated carbon and sulphur-impregnated activated carbon. Experimental results from this study showed the types of activated carbon, chemical composition of the flue gas stream, and reaction of mercury with surface functional groups could affect mercury vapor uptake by the adsorbents.

Volatile Organic Compounds (VOCs) are common pollutants emitted from industrial processes. We have evaluated the performance of the packed and fluidised beds on the removal of VOCs from simulated gas streams. The rate of adsorption was found experimentally to be higher in the fluidised bed compared to the packed bed, when both the gas velocities and residence time were kept constant.

Environmental monitoring and occupational health

We have studied environmental exposure and occupational health of workers exposed to silica dusts as they performed various job functions in granite quarries. Experimental results published in papers were among the first in identifying the translation of silica exposure to not only the dysfunction of the lungs, but also to nephrotoxicity. Besides silica dusts, our research has also extended to other pollutants such as polyvinylchloride dusts and lead.

Current Research Projects

• Research in Aging
• Development of a Scale-Up Platform for Cell Therapy
• Bioreactor and Bioprocess Development for the Production of a Value-Added Food Product

Areas for PhD Supervision/Potential PhD Projects

• Stem cells, tissue engineering and regenerative medicine. 
• Aging
• Bioreactor and bioprocess development for production of biochemicals and proteins. 
• In-situ product recovery as a bio separation strategy to improve bio production.
• Pollution abatement technologies
• Environmental monitoring and occupational health.  

PhD / MPhil students

Potential students are welcome to send me an email if you have interest in pursuing a PhD or MPhil.

Professional activities

Reviewer for journal publication

Industrial consultation and collaboration