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TSCA Environmental Release Application (TERA) for Alcaligenes xylosoxidans subspecies denitrificans strain AL6.1

On June 25, 2003, the Office of Pollution Prevention and Toxics approved the TSCA Environmental Release Application (TERA) under the biotechnology regulations promulgated under the Toxic Substances Control Act (TSCA). The TERA, submitted by University of California, Riverside, involves field trials of a modified strain of Alcaligenes xylosoxidans subspecies denitrificans, strain AL6.1. The TERA was given the tracking designation of R-03-0001. The microorganism has been modified to carry a coding sequence of DsRed for expressing a red fluorescent protein. The microorganism will be applied to four contained sites, including three vineyards, to study the bacterium’s biology and behavior in the vineyard ecosystem. The submitter will assay grape plants to determine whether they contain the fluorescent modified strain. Eventually, researchers hope to develop a pesticidal strain that will deliver a reagent to counteract Pierce’s disease in grapes. The field trials will run from July 1, 2003 until the end of the growing and harvest season.

Regulatory Background

The EPA requirements concerning microbial products subject to TSCA (15 U.S.C. Section 2601, et seq.) are set forth in “Microbial Products of Biotechnology; Final Regulation under the Toxic Substances Control Act” (62 FR 17910 (April 11, 1997)) and codified at 40 C.F.R. Part 725. Microorganisms resulting from the deliberate combination of genetic material originally isolated from organisms of different taxonomic genera (intergeneric microorganisms) constitute “new” microorganisms subject to TSCA Section 5 notification requirements. Persons who manufacture, import, or process intergeneric microorganisms for commercial purposes subject to EPA jurisdiction under TSCA, are required to submit a Microbial Commercial Activity Notice (MCAN). Persons conducting commercial research and development activities may submit a TERA, instead of an MCAN, before initiation of such testing. EPA conducts a review of these submissions to determine whether the intergeneric microorganisms present an unreasonable risk to health or the environment. The Agency can impose regulatory controls under section 5 of TSCA.

Summary of the Risk Assessment

Based on available data, there is low concern for potential toxicity of the recipient microorganism and the introduced genetic material. The recipient microorganism is not a frank pathogen. The recipient microorganism, Alcaligenes xylosoxidans subspecies denitrificans, is a gram-negative aerobic bacterium that occurs in soil and water. It has been found in the human normal flora of the ears, skin, and GI tract as well.

There are no available data regarding toxicity associated with exposure to the DsRed red fluorescent protein. Because this TERA is for a small field trial, the limited potential exposure to DsRed mitigates concern for possible toxicity. While there is a potential for transfer of the DsRed gene to other organisms, the probability is low. Therefore, the Agency identified no significant risk with the small-scale field trials.


The Agency determined that the proposed small scale field trials of the intergeneric microorganism will not present an unreasonable risk of injury to health or the environment. In the TERA approval letter, EPA advised the submitter that future intergeneric strains should have the DNA inserted into the chromosome. Additionally, the letter stated that each grape plant should be destroyed at the end of the experiment and surrounding soil treated according to methods approved by EPA.

For a copy of the original nonconfidential TERAs and the nonconfidential approval letter, please contact the TSCA Non-Confidential Information Center (NCIC) by phone at (202) 566-0280, or by fax at (202) 566-9744.