Initial risk assessment of genetically modified (GM) microalgae for commodity-scale biofuel cultivation

Genetic modification (GM) of microalgae to improve commercial production of biofuels is underway. Inevitable governmental regulations will likely address environmental, economic and human health impacts. Proactive addressing of such regulatory protection goals should begin now, during early development of this new, potentially large and transformative industry. We present strategies for ecological risk assessment of GM algae for commercial mass cultivation assuming that escape of GM algae into the environment is unavoidable. We consider the potential ecological, economic and health impacts of GM algae that persist in and alter natural ecosystems. Horizontal gene transfer with native organisms is of particular concern for certain traits, especially when cultivating GM cyanobacteria. In general, we predict that most target GM algal traits are unlikely to confer a selective advantage in nature, and thus would rapidly diminish, resulting in low but nonzero ecological risk. Genetic and mechanical containment, plus conditional matching of GM algal traits to unnatural cultivation conditions, would further reduce risk. These hypothetical predictions must be verified through rigorous ongoing monitoring and mesocosm experiments to minimize risk and foster public and regulatory acceptance.

► Regulatory endpoints for genetically modified algae must be addressed proactively.
► Most target GM algal traits are likely to have low but nonzero ecological risk.
► Matching of GM algal traits to unnatural cultivation conditions would reduce risk.
► Horizontal gene transfer with wild organisms may be a potential risk in some cases.
► Genetic and mechanical containment, monitoring and mesocosm experiments are essential.