Our current research program covers two important areas in bioprocessing and bioengineering. The first one is animal cell culture and tissue engineering; the second one is bioprocessing for value-added products. 
Animal Cell Culture and Tissue Engineering
 We have developed a perfusion bioreactor with a fibrous matrix to support high-density, viable cell population for long-term production of recombinant proteins and tissue engineering of human cells. We have found that the 3-D fibrous matrix has profound effects on cell spatial organization, morphology, and cell-cell contacts and interactions, which in turn affect cell proliferation, differentiation, and functions. Cells grown in the fibrous matrix maintained better long-term stability, as compared to those grown in T-flasks. Ovary luteal cells cultured in the 3-D matrix maintained their cellular function to secrete progesterone, while cells cultured in the 2-D static flask lost most of their response in the same culturing period. 

We are working on tissue engineering of human cells for various biomedical applications. For example, an in vitro human placenta model system based on tissue engineering of human trophoblast cells is being developed for drug screening and toxicology studies. 

Bioprocessing for Value-Added Products

It is important for agricultural and food industries to increase their product values through the uses of modern biotechnology and bioprocesses. Our work has been concentrated on the development of several novel bioprocesses for economical production of high-value products from food processing wastes and agricultural commodities. Our recent and ongoing research projects include fermentation of whey permeate and plant biomass to produce various organic acids and microbial polysaccharides, steroid biotransformation, and immobilized enzyme for galactooligosaccharides (GOS) production. These bioprocesses are important to the agricultural industry and address important environmental issues. One example is the process we developed to convert whey permeate, a dairy waste, to environmentally friendly, non-corrosive road deicers. 

We take an integrated approach to solve an important bioprocess engineering problem: a patented fibrous-bed bioreactor is developed to increase productivity and cell tolerance to a high-concentration of inhibitory metabolites; membrane separation and solvent extraction are used to separate and concentrate fermentation products; and genetic and metabolic engineering of production cells are used to further improve product yields and process efficiency. We are also interested in applying our technology in the environmental area, such as biofiltration of VOC and biodegradation of hazardous chemicals in industrial waste streams and contaminated groundwater.