June 28, 2000

UMBI "GREEN" CHEMISTRY RECYCLES CRAB SHELL WASTE

WASHINGTON, D.C. -- New research in the chemistry of chitosan - a polymer that is a byproduct of crab shell recycling in Maryland - is enabling the creation of a wide range of environmentally friendly products for uses ranging from better cosmetics to oil drilling fluids.

In a presentation today at the fourth annual Green Chemistry and Engineering Conference, held at the National Academy of Sciences, Gregory F. Payne, professor at the University of Maryland Biotechnology Institute (UMBI), explains how research has led to large volumes of new chitosan being produced at a shell recycling plant in Maryland. The conversion of crab shell waste into useful chitosan began as a marketing and engineering project four years ago at UMBI's Center for Agricultural Biotechnology (CAB), says Payne.

"Our research team is changing the basic chemistry of the chitosan in order to create new products such as water-resistant adhesives, lubricants for oil drilling, and thickeners for cosmetics and other consumer products," Payne explains. Chitosan is made from chitin, the structural substance in shells of crabs, other crustaceans, and insects. It is also found in some fungi.

"We are using naturally occurring enzymes to change chitosan - essentially, we are using green chemistry to make it do a lot of new things," says Payne. The parent substance, chitin, he adds, is the second most common biological material on earth, after cellulose. But, contrasted to industrial-scale cellulose products such as paper goods, cotton clothing, and additives to shampoos, chemists have invested far less research into converting chitin's derivative chitosan into industrial products, he says.

"In this country, I think most people who want to market chitosan are looking to useit in a medical drug with considerable profit potential," comments Payne. "But, this state has so much material (crab shells), that such an approach won't use up the abundant chitosan we get from crab waste. After all, we started this project to address a waste problem, since Maryland generates about 10 million pounds of crab shells annually."

Payne says his research evolved from state efforts to reduce nutrient loading of such wastein the Chesapeake Bay watershed. New regulations limit direct dumping of crab shell waste, or chum, into waterways. Farmers need permits to spread chum as a fertilizer. The Beulah Land Fill in Dorchester County, (location of a majority of the state's crab picking/packing companies), charges $38.25 per ton to dispose of chum.

To find alternatives, the state encouraged a private company, New Earth Services, to begin composting the crab wastes in 1992. NES composts the waste into garden mulch that partially offsets, but does not eliminate, the costs for disposal of the packer's wastes. In 1996, Dan Healey, director of investment financing with the Maryland Department of Business and Economic Development, introduced officials of the Louisiana-based specialty chemical producer, Venture Innovations, Inc. to Pat Condon, NES general manager, and to UMBI's Payne. The collaboration led to the chitosan from crab chum production process.

The crab recycling plant is a partnership of NES and Venture. Called Chitin Works, Inc., it is located in Cambridge, Dorchester County and accepts waste from crab packers for free. Payne notes, "Imposing more stringent environmental regulations might have driven crab-packers out of business. But I think this project shows that government agencies and university researchers can work with private companies to provide more enlightened options." He said the crab shell-to-chitosan partnership has transformed an environmental problem into a business opportunity.

Payne says that a major advantage of producing industrial products from chitosan, over other polymers, is its unique chemical structure. "It is very reactive, allowing us to graft on many other compounds to confer new functions, such as making it dissolve in liquids. Cellulose, by contrast, is more difficult to make water soluble," he adds. Payne's team is now using the natural enzyme tyrosinase as a biochemical approach to improve other useful qualities of crab shell chitosan.

Last year, Payne and co-workers at CAB received half of a $400,000 National Science Foundation (NSF) grant to change crab shells into new forms of chitosan. The new funding is a phase II small business grant that awarded to Venture. UMBI is a research subcontractor under the grant.

Condon says that Chitin Works can process up to 3,000 tons of crab chum this summer. For every 24 tons, the company can produce one ton of chitosan, with the excess solids going to the NES composting site nearby. He adds that crab waste, disposed in other ways, "can be a nasty, smelly by-product of the crab industry. But, we create a clean resource from it. Because of quick and efficient processing, we have no odor problem and no pollution from the plant."