Research

1. Developing an Environmental-Friendly Bio-conversionn Process to Cellulosic Ethanol Biorefining

By focusing on two major global concerns -- energy and environment, our research will provide an innovative ethanol production system, which improves cellulosic-ethanol system and reduces the environmental impacts that traditional cellulosic-ethanol systems have, and further contribute to providing new economic opportunities to develop sustainable agriculture and industry with less reliance on fossil fuels. Some specific research topics include: (1) enhancing ligninase production on lignocellulosic materials using a pelletized fungal fermentation; (2) developing an enzyme mixture with enhanced performance for environmentally benign biological pretreatment and hydrolysis of the feedstock; (3) improving ethanol fermentation on C-5 and C-6 sugars; (4) developing a integrated ethanol production system on lignocellulosic materials.

2. High Rate Fermentative Organic Acid Production by Innovatively Pelleting Filamentous Fungus -- Rhizopus oryzae

Fungal fermentation plays a key role in biorefinery as almost all of the top value added chemicals identified by the Department of Energy can be produced form biomass via fungal or yeast fermentation. Rhizopus oryzae, in particular, is an important fungal organism capable of producing various products via different pathways. As a filamentous fungus however, R. oryzae usually develops a cotton-like morphology that results in low yield and productivity in organic acid production, and thus is undesirable for the fermentation processes. The aim of this study is to develop an innovative process, using R. oryzae as a model microorganism that changes the morphology of the filamentous fungus to a pellet form that is more efficient than cotton-like morphology in fermentation. The ultimate goal of the effort is to optimize this novel process to make the fungal fermentation not only competitive with bacteria fermentation in terms of yield and productivity, but also more suitable than bacteria for applications to lignocellulosic hydrolysates that often contain inhibitory substances which are more detrimental to bacteria than to fungi. Specific objectives include: (1) refining the pellet formation process to produce the desired size and number of pellet nuclei for various fermentation needs, (2) developing a set of mathematical models that describe the growth kinetics of the microorganisms, the development of the fungal pellets, and the pellet-broth mass transfer process, (3) maximizing organic acid production by controlling operational parameters for optimal pellet growth and utilization, and (4) testing the technology in fermentation using lignocellulosic-derived sugar streams.

3. Anaerobic Digestion of Animal Manure

Vast amounts of farm animal manure produced in the United States have the potential to be converted into economic gain if the proper processing technology is employed. Anaerobic digestion (AD) is such a technology. It not only can provide pollution prevention, but also converts manure into profitable bioenergy and chemcial products, namely, methane biogas, fiber, and digestate, each which can be used, respectively, as fuel, soil amendment, and liquid fertilizer. AD is an established technology but low growth rates of anaerobic bacteria and difficulties with biodegradation of lignocellulosic materials are stifling wide adoption of AD in manure management. The project is to develop an innovative AD system with enhanced cellulosic degradation related microbial community for lignocellulosics rich animal manure such as dairy manure and cattle manure. The specific objectives are: (1) identifying the current available hemicellulose/lignin related microorganisms in the anaerobic digestion system, (2) investigating the effects of hemicellulose and lignin degradation on biogas production, (3) developing and optimizing the design of an novel plug flow anaerobic digestor with enhanced microbial community for cellulose degradation.