Methodological Review of Genetic Engineering Approaches for Non-Model Algae

Despite the tremendous potential of algae to contribute to a future bioeconomy, there are practical and theoretical limitations to how well naturally sourced species can perform in an outdoor setting. The application of biotechnology to modulate and engineer algae metabolism, with the aim of increasing biomass productivity, directing carbon towards a favorable composition, resilience to pests, or producing novel molecules, offers opportunities to overcome some of the major commercialization barriers. There are numerous rational genetic engineering approaches documented in the literature having variable rates of success yet often lacking a thorough discussion on the potential underlying causes of the unsuccessful attempts. We critically review the documented methodology and approaches of recently reported genetic engineering successes of non-model algae. In particular, we focus on the identification of complications reported in recent literature based on native algae defense and resistance mechanisms relating to genetic engineering. The goal of this work is to provide insights into common mechanisms and suggest approaches that may help to develop successful genetic engineering strategies in non-model algae.