San Diego, California
February 21, 2003

Diversa Corporation (Nasdaq: DVSA) today announced that it has completed the transactions with Syngenta AG announced in December of last year. Under the transactions, the companies have formed an extensive research and product development alliance, and Diversa has acquired certain technology rights from Syngenta for pharmaceutical applications.

At a special meeting held yesterday, Diversa stockholders approved the issuance to Syngenta of shares of Diversa common stock and a warrant to purchase shares of Diversa's common stock, as described in Diversa's proxy statement filed with the U.S. Securities and Exchange Commission on January 14, 2003. At the closing, Diversa issued to Syngenta 6,034,983 shares of common stock and a warrant to purchase 1,293,211 shares of common stock at $22 per share that is exercisable for ten
years starting in 2008. Beginning next week, 77 employees from Syngenta's Torrey Mesa Research Institute (TMRI) will relocate to Diversa to begin work under the research and product development alliance, representing an initial commitment of $118 million over seven years from Syngenta. Diversa will also begin integrating the licensed technologies developed at TMRI into Diversa's pharmaceutical platforms and research programs. Additionally, 19 TMRI employees will relocate to Syngenta's research center in Raleigh, North Carolina.

"Our relationship with Syngenta has been successful to date, and we are eager to intensify our product development efforts under this new and expanded collaboration," said Jay M. Short, Ph.D., Diversa president and chief executive officer. "Together with Syngenta, we are ready to begin work under this agreement with the shared goal of rapidly developing products."

"Diversa has proven itself to be a valuable partner in the discovery and development of innovative products. Our Zymetrics joint venture has been successful in accelerating product commercialization, and we anticipate the launch of Zymetrics' first product within a year," said Dr. David Lawrence, Syngenta head of Research & Technology. "This new collaboration will provide us with a significant opportunity to extend our biotechnology capability and bring innovative products to market."

Diversa Corporation is a leader in applying proprietary genomic technologies for the rapid discovery and optimization of novel products from genes and gene pathways. Diversa is directing its integrated portfolio of technologies to the discovery, evolution, and production of commercially valuable molecules with pharmaceutical applications, such as optimized monoclonal antibodies and orally active drugs, as well as enzymes and small molecules with agricultural, chemical, and industrial applications. The Company has formed significant joint ventures with The Dow Chemical Company (named Innovase LLC) and with Syngenta Seeds AG (named Zymetrics, Inc.) focused on near-term commercialization of products for the industrial and agricultural markets, respectively. In addition, the Company has formed alliances with market leaders, such as Celera Genomics, The Dow Chemical Company, DuPont Bio-Based Materials, GlaxoSmithKline plc, Invitrogen Corporation, and Syngenta Biotechnology, Inc.