Staff Profile

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 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 

Undergraduate

• CHE2015 Engineering Practice
• CHE2022 Process Safety (Module Lead)
• CHE2023 Reactor Engineering 2

Postgraduate

• NUS8100 Legislation Safety Case and Incident Investigation (Module Lead)
• NUS8101/8203 Environmental Impact Legislation and Engineering
• NUS8110 Safety Engineering and Loss Prevention
• NUS8111 Biosafety Engineering and Occupational Health
• NUS8109 Project Dissertation

• Zhang Y, Ng YL, Goh KL, Chow Y, Wang S, Zivkovic V. Fluidization of fungal pellets in a 3D-printed micro-fluidized bed. Chemical Engineering Science 2021, 116466.
• Zhang Y, Ng YL, Goh KL, Chow Y, Wang S, Zivkovic V. Fluidization of fungal pellets in a 3D-printed micro-fluidized bed. Chemical Engineering Science 2021. In Preparation.
• Zhang Y, Goh KL, Ng YL, Chow Y, Wang S, Zivkovic V. Process intensification in micro-fluidized bed systems: A review. Chemical Engineering and Processing - Process Intensification 2021, 164, 108397.
• Ling W-L, Su CT-T, Lua W-H, Poh J-J, Ng Y-L, Wipat A, Gan SK-E. Essentially Leading Antibody Production: An Investigation of Amino Acids, Myeloma, and Natural V-Region Signal Peptides in Producing Pertuzumab and Trastuzumab Variants. Frontiers in Immunology 2020, 11, 604318.
• Ling WL, Ng YL, Wipat A, Lane DP, Gan SKE. The Quantification of Antibody Elements and Receptors Subunit Expression Using qPCR: The Design of VH, VL, CH, CL, FcR Subunits Primers for a More Holistic View of the Immune System. Journal of Immunological Methods 2020, 476, 112683.
• Zhang Y, Ling Ng Y, Goh KL, Wang S, Zivkovic V. Experimental Study of a 3D-Printed 3-Phase Miniaturized Fluidized Bed for Bioprocessing Screening. In: Fluidization XVI. 2019, Guilin, China: AIChE.
• Ng YL. Embedding Critical and Creative Thinking in Chemical Engineering Practice. In: 1st IEEE International Conference on Knowledge Innovation and Invention (ICKII). 2018, Jeju Island, South Korea: IEEE.
• Ng YL, Kuek YY. In-situ product recovery as a strategy to increase product yield and mitigate product toxicity. The Open Biotechnology Journal 2013, 7, 15-22.
• Ng YL. 3rd Annual Miniaturisation Event – Micro Scale Bioprocess Development. Honnao, 2013. Meeting Report from the Euroscicon event held on 14th November 2012.
• Ng YL, Chase HA. Novel bioreactors for the culture and expansion of aggregative neural stem cells. Bioprocess and Biosystems Engineering 2008, 31(5), 393-400.
• Ng YL, Chase HA. Separation and enrichment of neural stem cells using segregation in an expanded bed. Biotechnology Letters 2007, 29(11), 1745-1751.
• Yan R, Ng YL, Chen XG, Geng AL, Gould WD, Duan HQ, Liang DT, Koe LCC. Batch experiment on H₂S degradation by bacteria immobilized on activated carbons. Water Science & Technology 2004, 50(4), 299-308.
• Yan R, Chin T, Ng YL, Duan HQ, Liang DT, Tay JH. Influence of surface properties on the mechanism of H₂S removal by alkaline activated carbons. Environmental Science and Technology 2004, 38, 316-323.
• Chen XG, Geng AL, Yan R, Gould WD, Ng YL, Liang DT. Isolation and characterization of sulphur-oxidizing Thiomonas sp. and its potential application in biological deodorization. Letters in Applied Microbiology 2004, 39, 495-503.
• Geng AL, Chen XG, Gould WD, Ng YL, Yan R, Lee CC, Liang DT. Removal of odorous sulphur-containing gases by a new isolate from activated sludge. Water Science & Technology 2004, 50(4), 291-297.
• Ng YL, Yan R, Chen XG, Geng AL, Gould WD, Liang DT, Koe LCC. Use of activated carbon as a support media for H₂S biofiltration and effect of bacteria immobilization on available pore surface. Applied Microbiology and Biotechnology 2004, 66, 259-265.
• Ng YL, Yan R, Tsen L, Yong LC, Liu M, Liang DT. Volatile organic compound adsorption in gas-solid fluidized bed. Water Science & Technology 2004, 50(4), 233-240.
• Yan R, Ng YL, Liang DT, Lim CS, Tay JH. Bench-scale experimental study on the effect of flue gas composition on mercury removal by activated carbon adsorption. Energy & Fuels 2003, 17(6), 1528-1535.
• Ng TP, Ng YL, Lee HS, Chia KS, Ong HY. A study of silica nephrotoxicity in exposed silicotic and non-silicotic workers. British Journal of Industrial Medicine 1992, 49(1), 35-37.
• Ng TP, Phoon WH, Lee HS, Ng YL, Tan KT. An epidemiological survey of respiratory morbidity among granite quarry workers in Singapore: chronic bronchitis and lung function impairment. Annals of the Academy of Medicine, Singapore 1992, 21(3), 312-317.
• Ng TP, Phoon WH, Lee HS, Ng YL, Tan KT. An epidemiological survey of respiratory morbidity among granite quarry workers in Singapore: radiological abnormalities. Annals of the Academy of Medicine, Singapore 1992, 21(3), 305-311.
• Lee HS, Ng TP, Ng YL, Phoon WH. Diurnal variation in peak expiratory flow rate among polyvinylchloride compounding workers. British Journal of Industrial Medicine 1991, 48(4), 275-278.
• Ng TP, Goh HH, Ng YL, Ong HY, Ong CN, Chia KS, Chia SE, Jeyaratnam J. Male endocrine functions in workers with moderate exposure to lead. British Journal of Industrial Medicine 1991, 48(7), 485-491.
• Ng TP, Lee HS, Low YM, Phoon WH, Ng YL. Pulmonary effects of polyvinylchloride dust exposure on compounding workers. Scandinavian Journal of Work, Environment & Health 1991, 17(1), 53-59.