Recent advances in genetic engineering of microalgae: bioengineering strategies, regulatory challenges and future perspectives

Microalgae are being studied for nutraceuticals, medicines, and other industrial applications due to their metabolic capabilities in generating a wide range of bioproducts. However, inadequate yield and productivity are recurring issues for the commercial use of microalgae and their bioproducts. Despite promising global market, the industrial biotechnology sector has been slow in adapting to genetically modified (GM) microalgae due to various regulatory and scalability challenges. In this review, genetic modification tools like CRISPR, ZFN, TALEN, RNAi, synthetic biology, metabolic engineering techniques and high throughput screening platforms in different microalgal strains are discussed. Recent progress in microalgal genetic engineering and strain improvement in industrial applications such as biomass production, biomolecules production and process improvement are also highlighted. Lastly, the regulatory issues and biosafety issues in the use of genetically engineered microalgae in industrial and commercial applications, as well as the risk assessments such as hazard and exposure assessments are described.