Development of a Chimeric Biopesticide for the Treatment of Zebra and Quagga Mussels

Project ID: 19186
Principal Investigator: Kevin Kelly
Research Topic: Invasive Species
Funded Fiscal Years: 2019 and 2020
Keywords: None

Research Question

Currently, no approved treatments of zebra and quagga mussels provide effective eradication strategies in open
water. There are currently no biopesticides utilizing immunotoxin technology for the remediation of aquatic nuisance
species. Engineered toxin body (ETB) and Immunotoxin technologies are well validated in human health applications
and can be utilized for environmental application. Production of such biopesticides in commercial micro-algae
production vectors offer a low cost, high yield solution. This approach lowers the risk of unintended harm to native
ecologies, lowers production cost, and requires a lower effective dose than previously approved biopesticides.

Need and Benefit

Currently, there are no approved biopesticides capable of effective open water mitigation or eradication. While
advances in activated copper-based treatments have been made, these treatments may not be available for use in
open waters where native mussels are present or sensitive invertebrates valuable to the local ecosystem. The project
outlined in this project aims to provide the Bureau of Reclamation with a cost-effective, scalable, and safe product for
the treatment of zebra and quagga mussel infested waters. The research proposed here builds on research already
completed by bureau of reclamation, furthering goals previously established by the agencies and providing additional
characterization of previously completed research (Johnson 2015). Bureau of Reclamation resources which could be
positively impacts by the proposed research include all water bodies infested with zebra and/or quagga mussels,
associated water infrastructure, recreational areas, native ecosystems, and species at risk due to limnological
changes caused by zebra and quagga mussel infestation.
With the predicted cell kill efficiency and intracellular concentration of biopesticide in production cells, the effective
dose will be low enough to drive the cost below $1 per acre foot treated, however, the ability to effectively scale to
achieve this goal will vary depending on the species used for production. Use of a Schizochytrium production vector
will likely allow for efficient scaling to the necessary amount to provide sufficient cost suppression, as this species can
be produced heterotrophically in a commercial bioreactor already on site at the company and readily available within
the industry (Qu 2013; Banuelos-Hernandez 2017). Use of the commercial production strain in a bioreactor can
provide cell densities exceeding 80g/L in a 10L bioreactor within 48 hours (Song 2015; Banuelos-Hernandez 2017).
The media used in this process utilizes maize starch as a carbon source, soybean meal as a nitrogen source, and salt
- all inexpensive and readily available (Song 2015). Provided cell kill efficiency meets expectations, this process could
easily be scaled effectively for low cost, large batch production. The final cost of this production would be relatively
speculative at this time, though it is likely that the cost could reasonably be driven below the stated goal of $1 per acre
foot treated. The use of a Chlamydomonas production vector offers lower cost at large batch scale, but higher cost
with initial development and small batch production, as this species is photosynthetic and small-scale photo-reactors
are more-costly to operate than commercial, bench-top bioreactors. At scale, however, Chlamydomonas culturing for
the purpose of recombinant protein production, is well studied and low cost compared to other microalgae systems
(Rasala 2010; Davis 2016). Commercial production of transformed Chlamydomonas carries an estimated cost of
$406-612 per ton (907kg) dry mass product depending on production pond size (2-10 acre) (Davis 2016). At a
conservative estimate of an effective dose of 200g product per acre foot treated, the production cost in this type of
system would range from $0.09 to $0.14 per acre foot effective dose.
Currently, there is no effective treatment for zebra and quagga mussel infestation. Pursuit of this project improves the
likelihood of a cost-effective product, capable of treating infested water bodies, becoming available. Mitigation of
Dreissena infestation requires substantial annual capital investment in the form of screens, manual removal costs,
chemical treatment of water in transit, etc. The sooner eradication becomes a reality, the lower the long-term cost.

Contributing Partners

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Research Products

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Last Updated: 6/22/20