Research Project Summary Information
Biodegradable Plastics from Levulinic Acid(ST6737-1)
SUNY Research Foundation
Polyhydroxyalkanoates (PHAs) are naturally produced compounds that can be used as high-value biodegradable thermoplastics. Researchers hope to grow PHAs using two inexpensive examples of feedstocks: xylan from fast-growing willows and levulinic acid also derived from renewable resources. While early PHAs were brittle, a co-polymer can be made that maintains strength and flexibility, acting like polypropylene, and potentially having uses as a biodegradable paper coating. (The ratio of each monomer in the copolymer affects characteristics such as strength and melting temperature). Bacterial strains that use carbohydrates and levulinic acid already have been identified; researchers here will try to use lower-cost xylan rather than other carbohydrates. Current estimates using carbohydrates predict a production cost of $3.50/kg. A cost as low as $1.50/kg is possible through better bacterial strains, improved fermentation, better product recovery, and cheaper feedstocks.
Researchers developed a process for biosynthesis of PHA from two inexpensive examples of feedstocks, xylan and levulinic acid.
Researchers successfully demonstrated PHA production from xylan, rather than glucose, while demonstrating that levulinic acid will provide sufficient valeric acid content (25 28%) in the product. Commercialization of these successes could lead to a value added use for willows, diversify the options for NYS farm crops, and help develop a new NYS biomass based chemical industry. A viable biomass based industry will develop as product prices approach those of their petrochemical counterparts. The biodegradable nature of the product has environmental advantages.
Cultures were screened for the ability to produce high yields of polyhydroxyalkanoates (PHAs) from xylose and levulinic acid. Burkholderia cepacia was chosen. Cell growth was optimized by varying carbon source concentrations, pH, salts mixtures, and trace elements. Highest yields were obtained using selective ratios of xylose and levulinic acid. Optimal production of xylose from xylan was established in collaboration with the Dept. of Paper and Bioprocess Engineering using a variety of “cook” times for hardwood chips. Based on the ratios of xylose and levulinic acid, a strong relationship was established between the concentration of levulinic acid in the medium and the molar ratio of the two subunits, ß-hydroxubutyric acid (HB) and ß-hydroxyvaleric acid (HV) present in the polymer. The HV controls the degree of flexibility of the polymer. The higher the HB content, the more stiff and brittle the polymer will be. Control of these properties will allow production of specific polymers to fit specific applications. The ration of HB and HV was established by NMR through the Chemistry Dept, at ESF. Physical characterization of copolymers included molecular mass, thermal decomposition temperature, glass transition temperature, and melting temperature, established as a function of the mole percent of HV. Numerous journal articles based on the work were published, including in the Journal of Industrial Biotechnology and Microbiology.
SUNY Research Foundation
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SUNY College of Environmental Science an
Indigenous/Renewable Energy Resources
NYSERDA Contact Information
R&D - Environment & Energy Res