San Diego, California
December 19, 2002

Diversa Corporation (Nasdaq: DVSA) today announced that it has successfully achieved all development milestones for the year in its joint venture collaboration with Syngenta (NYSE: SYT).
Diversa will receive an undisclosed milestone payment for delivering several animal feed product candidates as well as promising leads for other applications.

"We are particularly pleased to report the achievement of this milestone after announcing plans to greatly expand our relationship with Syngenta earlier this month," stated Bill Baum, Executive Vice President of Diversa's Chemical, Agriculture and Industrial Enzymes business group. "The ongoing success of our alliances with Syngenta has led us to broaden our fields of collaboration under additional agreements, and most importantly to generate promising product candidates."

Zymetrics is focused on the development and marketing of enzyme-based products and processes designed to enhance the nutritional content of animal feeds, improve the health and performance of animals, minimize the environmental impact of intense animal production, and enable new opportunities for novel products from the processing of agricultural outputs. Diversa is receiving research support, and will participate in profit sharing on products commercialized by the venture.

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.

In addition, Diversa recently announced that it had entered into a series of agreements with Syngenta Participations AG pursuant to which it and Syngenta will, among other actions, form a broad collaboration to establish a shared biotechnology research platform and to discover products. Consummation of Diversa's proposed transactions with Syngenta is subject to the approval of federal regulators under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, as well as approval of Diversa stockholders, among other conditions. The press release announcing Diversa's agreements with Syngenta has been filed as an exhibit to a Current Report on Form 8-K that Diversa filed with the Securities and Exchange Commission, or SEC, on December 4, 2002.