Bio-products

OTHER BIO-PRODUCTS

BIODEGRADABLE POLYMERS—MICROBIAL SYNTHESIS OF POLYMERS

Biodegradable polymers are an alternative to traditional petrolium based polymers and would help to reduce solid waste disposal problems associated with most plastics.

Researcher: Jim Kastner
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A NATURAL SWEETENER FROM RENEWABLE CARBON SOURCES

Researcher: Jim Kastner, jkastner@engr.uga.edu

Lignocellulosics are a large, but untapped renewable carbon resource within Georgia. The predominant polymer in many renewable lignocellulosic feedstocks is cellulose, which generates glucose upon hydrolysis. However, depending on the feedstock, large fractions of other six and five carbon sources are released when hemicellulose is hydrolyzed, particularly xylose. Xylitol is a natural alternative sweetener that can be produced by fermentation of xylose.

Lignocellulosics, such as soybean hulls, cottonseed hulls, and hardwood waste, are examples of large, but untapped renewable carbon sources within Georgia. The predominant polymer in many renewable feedstocks is cellulose, which generates glucose upon hydrolysis. However, depending on the feedstock, large fractions of other six and five carbon sources are released when hemicellulose is hydrolyzed, particularly xylose. Any process (e.g., ethanol production) designed to utilize these residues must produce a high-value product from xylose. We are developing a fermentation process to produce xylitol from xylose. Xylitol is a natural alternative sweetener that provides a cool oral sensation, can be utilized as a diabetic sweetener, and does not cause cavities. Xylitol is currently being used in a wide range of products: bakery products, spices, relishes, jams, jellies, chewing gum, confectionery products, pharmaceuticals, and oral hygiene products and sells for 2-7 dollars per lb. The microbial fermentation process is highly advantageous since it is selective and produces xylitol yields much higher than the chemical process.

Xylitol, as well other compounds that can only be derived from xylose, hold great potential in creating new high-value markets for agricultural and pulp and paper industries in Georgia. For example, if xylitol is sold at $7/lb and produced from cottonseed hulls (assuming 15% xylose in hulls and 80% xylitol yield) the potential exists to achieve a value $1680/ton of hulls compared to the current value of $44/ton @ $2.50 corn as roughage for cattle feed.

Xyliton Production Presentation:
www.engr.uga.edu/people/jkastner/IBE%20Xylitol.pdf