Bio-engineering of microalgae: Challenges and future prospects toward industrial and environmental applications

Microalgae are complex metabolic machineries whose potential has been continuously tapped for wide range of applications. Their suboptimal biomass yield and bioactives production remain the mainstay for their commercialization. To surpass the limitations, genetic engineering and its decisive role in strain improvement have led to the enhancement of quality and yield of products. Meanwhile, the sporadic use of genetic engineering tools specifically toward microalgal strains has limited their applicability. In this context, this article was mainly prepared to highlight the characteristics of microalgae and the introduction of omics approach for the improvement of strain for biorefinery processes. Furthermore, genome editing and gene-interfering tools to augment algal research using reference strains have been described. The progress made by genetic engineering in editing a gene using CRISPR-Cas9 and metabolic engineering of microalgae for biofuel production and CO₂ sequestration have been critically reviewed. As a futuristic alternative, the transgenic microalgae would compete with the existing resources reducing the dependency on fossil fuel in terms of cost, energy production, and efficacy.