Investor Relations

PRESS RELEASE June 2004
Marcia Miller, Director of Marketing
Metabolix, Inc., 21 Erie St.
Cambridge, MA 02139
617-492-0505 x227; fax: 617-492-1996
miller@metabolix.com

CAMBRIDGE, Mass. - Metabolix, Inc. has been honored as the 2003 recipient of Frost and Sullivan's Technical Insights Excellence in Biopolymers Research Award for its innovative biotechnology development of a renewable family of plastic materials. The award recognizes the company for its disruptive technology and overall research excellence, as well as its commitment to differentiating itself based on science-backed services or solutions.

The Metabolix innovation involves development of a robust, environmentally friendly, low-cost microbial fermentation process for converting renewable raw materials, such as sugars and plant oils, to a versatile range of plastic materials within the microbial cell. The process eliminates the need for the additional steps involved with chemical synthesis of polymers outside the cell. Metabolix's resulting polymer products, known as PHAs (or polyhydroxyalkanoates), exhibit the high performance and broad range of physical and mechanical properties of traditional plastics - but are made from renewable resources. And unlike most other such materials, they are both stable to water and biodegradable in fresh water, marine water, soil, and composting environments. They will even biodegrade in anaerobic environments.

"This award testifies to the high quality and cutting-edge innovation Metabolix employs in making renewable PHA plastics commercially competitive", said Dr. Oliver Peoples, Metabolix's vice president for research and chief scientific officer. "We can now convert sugars or plant oils to a family of PHAs that range from highly crystalline to highly elastomeric to soft and sticky - making them appropriate for a wide variety of applications, such as film, fiber, molded goods, and adhesives and coatings. Metabolix is also working on direct production of PHAs in plants, which will provide them at costs competitive even with polyethylene and polypropylene."

Frost and Sullivan, founded four decades ago to provide world-class market consulting on emerging high-technology and industrial markets, works in more than 50 countries around the world. To choose the award recipient, the firm's Technical Insights group tracks key hi-tech markets, considering the pace of research, technology innovation, and the significance or potential relevance of the research to overall industry. The analysts also consider the number and type of research projects, the caliber of the research staff, the potential of products to become an industry standard, and the breadth of intellectual property ownership.

Founded in 1992, Metabolix, Inc. uses sophisticated biotechnology to produce environmentally friendly performance plastics from renewable resources. Metabolix is the world leader in applying the advanced tools of metabolic engineering and molecular biology to efficiently produce PHA plastics in microbial systems and directly in non-food plant crops. The company is currently commercializing fermentation-based PHAs in applications where they provide unique performance benefits. For more information, please visit www.metabolix.com.