Metabolix, Inc. (NASDAQ: MBLX), a bioscience company focused on developing sustainable solutions for plastics, chemicals and energy, announced today that it has completed a field trial of tobacco, genetically engineered to express polyhydroxyalkanoate (PHA) biobased polymers. Metabolix obtained the necessary permits from the U.S. Department of Agriculture Animal Plant Health Inspection Service (APHIS) to perform an open air field trial in March of 2009 and field trial experiments were completed in early October. The trial was performed on 0.8 acres of land and provided valuable data and information relating to polymer production, with the best plants producing 3-5% PHA. This furthers development of Metabolix crop technologies for the co-production of biobased plastics in non-food bioenergy crops.

Dr. Oliver Peoples, Chief Scientific Officer of Metabolix, commented, “The experience and knowledge we have gained during our tobacco field trial is laying the groundwork for planning and permitting activities for field trials in bioengineered, non-food oilseed and biomass crops producing PHA. We believe that our crop programs offer a number of commercialization options and hold significant potential. We are excited to continue to push this technology forward and believe it will ultimately support a diverse array of bioengineered, environmentally conscious and economically viable alternatives to petroleum-based products.”

About Metabolix

Founded in 1992, Metabolix, Inc. is an innovation-driven bioscience company focused on providing sustainable solutions for the world’s needs for plastics, chemicals and energy. The Company is taking a systems approach, from gene to end product, integrating sophisticated biotechnology with advanced industrial practice. Metabolix is now developing and commercializing Mirel™, a family of high performance bioplastics which are biobased and biodegradable alternatives to many petroleum-based plastics. Metabolix is also developing a proprietary platform technology for co-producing plastics, chemicals and energy, from crops such as switchgrass, oilseeds and sugarcane.

For more information, please visit www.metabolix.com. (MBLX-G)

Safe Harbor for Forward-Looking Statements

This press release contains forward-looking statements which are made pursuant to the safe harbor provisions of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. The forward-looking statements in this release do not constitute guarantees of future performance. Investors are cautioned that statements in this press release which are not strictly historical statements, including, without limitation, statements regarding expectations for Metabolix research and development programs, constitute forward-looking statements. Such forward-looking statements are subject to a number of risks and uncertainties that could cause actual results to differ materially from those anticipated and are detailed in Metabolix's filings with the Securities and Exchange Commission, including its annual report on Form 10-K and quarterly reports on Form 10-Q. Metabolix assumes no obligation to update any forward-looking information contained in this press release or with respect to the announcements described herein.