Diversa and Valley Research Announce Additional FDA Regulatory Approval for Ultra-Thin™ Enzyme for More Efficient Ethanol Production

Marketing of Ultra-Thin™ enzyme to be expanded to all ethanol producers in U.S.

San Diego, CA, and South Bend, IN, February 27, 2006 - Diversa Corporation (Nasdaq: DVSA) and Valley Research, inc. announced today the receipt of regulatory approval from the U.S. Food and Drug Administration’s Center for Veterinary Medicine for Ultra-Thin™ enzyme, a new product designed to significantly improve the efficiency and economics of ethanol production from corn and other starch sources. Developed by Diversa and marketed under the Ultra-Thin label by Valley Research, this new product dramatically lowers the viscosity of the corn starch stream and operates at high temperature and at a lower pH than other commercially available enzymes, all of which offers ethanol producers the potential for substantial throughput advantages and cost savings.

Ultra-Thin enzyme is a novel, next-generation alpha amylase enzyme designed to offer ethanol producers superior liquefaction performance. It works in concert with other enzymes to efficiently convert the starch present in corn and other sources, into sugars that can then be processed into ethanol or other value-added products such as corn sweeteners. Ethanol producers have traditionally used other alpha amylase enzymes that do not significantly reduce the starch stream viscosity and do not operate at an optimal pH, limiting plant capacity and requiring costly process adjustments. Ultra-Thin enzyme is being distributed by Valley Research for fuel ethanol and sweetener applications. Diversa manufactures Ultra-Thin enzyme under its agreement with Fermic S.A. de C.V.

“We look forward to expanding the marketing of Ultra-Thin enzyme to ethanol producers throughout the U.S., particularly those whose mills stand to benefit most from the significantly higher throughput that can potentially be achieved by switching to this superior product,” stated Art Sears, President of Valley Research.

“Diversa has identified alternative fuels as a significant focus area, and Ultra-Thin is the first of what we hope will be several significant enzyme products for this rapidly growing industry,” said Edward T. Shonsey, Diversa’s Chief Executive Officer. “We believe Diversa’s ability to discover and optimize new enzymes with differentiated features, like Ultra-Thin enzyme, has the potential to transform the ethanol industry. Beyond Ultra-Thin enzyme, Diversa is working on longer-term programs to develop more cost-effective processes for producing ethanol, including so-called ‘cellulosic ethanol’ from biomass.”

According to the Renewable Fuels Association, the U.S. ethanol industry produced a record 4 billion gallons in 2005, representing an increase of 17% from 2004 and 126% since 2001. In addition to the 95 existing ethanol plants located in 19 states, at the end of 2005, 29 ethanol refineries and nine expansions were under construction with a combined annual capacity of more than 1.5 billion gallons.

About Valley Research, inc.

Valley Research, headquartered in South Bend, Indiana, is a leader in innovative enzymes for both food and industrial applications. With a diverse product line and unmatched technical support, Valley Research has been a preferred, specialty enzyme supplier for more than 20 years. www.ValleyEnzymes.com

About Diversa

Diversa Corporation is a leader in applying proprietary genomic technologies for the rapid discovery and optimization of novel protein-based products. Diversa is directing its integrated portfolio of technologies to the discovery, evolution, and production of commercially valuable molecules with agricultural, chemical, industrial, and pharmaceutical applications. Diversa has established alliances and joint ventures with market leaders, such as BASF, Cargill Health and Food Technologies, DuPont Bio-Based Materials, Medarex, Merck, and Xoma. In addition, Diversa has formed a broad strategic relationship with Syngenta AG, a world-leading agribusiness company. Diversa has commercialized products both independently and in collaboration with strategic partners and licensees. Additional information is available at Diversa’s website: www.diversa.com.

Forward-Looking Statements

Statements in this press release that are not strictly historical are “forward-looking” and involve a high degree of risk and uncertainty. These include statements related to the cost savings, efficiencies, and production and other benefits that may be realized from the use of Ultra-Thin enzyme, the ability and likelihood of Diversa’s and Valley Research’s successfully marketing and commercializing Ultra-Thin enzyme, Diversa’s ability to develop additional products for the alternative fuels arena, and Diversa’s and/or its products’ ability to transform the ethanol industry, all of which are prospective. Such statements are only predictions, and the actual events or results may differ materially from those projected in such forward-looking statements. Factors that could cause or contribute to differences include, but are not limited to, risks involved with Diversa’s new and uncertain technologies, Diversa’s dependence on patents and proprietary rights, Diversa’s protection and enforcement of its patents and proprietary rights, Diversa’s dependence on Valley Research in connection with Ultra-Thin enzyme, including for commercialization of Ultra-Thin enzyme, Diversa’s ability to maintain its collaboration with Valley Research, Valley Research’s ability to sell Ultra-Thin enzyme, whether customers will purchase Ultra-Thin enzyme and realize the anticipated cost-savings and efficiencies, the degree to which Diversa is able to realize economic benefits from cost-savings of ethanol producers, and the development or availability of competitive products or technologies. Certain of these factors and others are more fully described in Diversa’s filings with the Securities and Exchange Commission, including, but not limited to, Diversa’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2005. These forward-looking statements speak only as of the date hereof. Diversa expressly disclaims any intent or obligation to update these forward-looking statements.

Note: Ultra-Thin is a trademark of Valley Research, inc.

Contact Information

Martin Sabarsky

Diversa Corporation

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