EMERGING RESEARCH FRONTS - 2008

Why do you think your paper is highly cited?

Our paper provides a comprehensive review of ethanol production from lignocellulosic materials, including the work that has been done in the past, the current research status, and future perspectives in this area.

How did you become involved in this research and were any particular problems encountered along the way?

I had worked in ethanol fermentation in the late 1980s and early 1990s. In the last 10+ years, I have been working on the conversion of organic waste, specifically swine waste, into bioenergy through anaerobid digestion and clean-up of the wastewater.

In many swine farms in the South and Southeast, the farmers grow coastal Bermuda grass as a part of their nutrient management plan for the treatment of their swine waste. However, some farmers have difficulty selling their Bermuda grass as a product, which led us to a research project on conversion of coastal Bermuda grass to fuel ethanol in 1999. We have been investigating coastal Bermuda grass, switchgrass, and rye straw since then.

Where do you see your research leading in the future?

One of the big challenges in converting lignocellulosic materials into ethanol is the high lignin content that blocks the access of cellulase enzymes or chemicals to cellulose during hydrolysis. Therefore, a pretreatment is necessary to remove lignin from the materials, prior to further processing, which is one of the main reasons a lignocellulosic biomass-to-ethanol technology is too expensive for commercialization.

I am currently working with my colleagues in using genetic transformation techniques to generate transgenic switchgrass that has much lower lignin. Hopefully the expensive pretreatment process can be avoided in converting low-lignin transgenic switchgrass into ethanol.

Do you foresee any social or political implications for your research?

Our research has been focused on converting grasses such as switchgrass and coastal Bermuda grass into fuel ethanol. Unlike corn, these grasses can grow on marginal land and do not compete against food and feed production. Furthermore, these grasses have high yields of dry biomass production, e.g. switchgrass can produce around 10 metric tons per acre per year.

Their growth does not require extensive fertilization. Commercialization of grasses-to-ethanol technology would provide a sustainable biofuel production and reduce our nation's dependency on foreign oil, create jobs in feedstock farming, ethanol production, and related work, and significantly reduce carbon dioxide emission which is critical in preventing the global climate change from worsening.

Jay J. Cheng, Ph.D.
Professor
North Carolina State University
Biological & Agricultural Engineering Dept
Raleigh, NC, USA

Keywords: hydrolysis, lignocelluousic materials, lignin, ethanol, ethanol fermentation, swine waste, Bermuda grass, transgenic switchgrass, rye straw, cellulase enzymes.