Towards Environmental Sustainability: Employing Adaptive Laboratory Evolution to Develop Elite Algae Strains for Industrial and Environmental Applications

Purpose of Review

Algae hold immense potential for industrial and environmental applications for their efficient carbon fixation and producing a range of valuable metabolites. However, their commercial cultivation is still challenging because of compromised productivities under various environmental stress conditions. Therefore, elite strains capable of commercial production should be developed. Although, significant progress has been made in metabolic pathway engineering techniques, due to the complexity of metabolic and regulatory networks of algae, rational bioengineering remained inefficient for strain improvement. This review has assessed the role of Adaptive Laboratory Evolution (ALE) as a promising and cost-effective alternative approach in developing elite algae strains for improved carbon capture, enhanced biomass production, and improved metabolite productivities to meet the robust commercial needs.

Recent Findings

ALE involves selecting the mutant cells under controlled selection pressure, where cells are exposed to a sequentially rising set of stress conditions over multiple generations to finally adapt and evolve desired phenotypes. It leads to the activation of inactive pathways that are suitable for the survival of strain in stress conditions. A brief view of ALE-assisted cultivation techniques shows its specificity for specific goal to develop its product-oriented applications. Furthermore, involving biosensor and robotics in ALE technology has indicated the potential of ALE process as a robust technique to rapidly develop elite strains to meet rising environmental and industrial demands. 

Summary

Assessment of ALE-assisted strain improvement has shown its potential to improve algae strains for the overproduction of desired products without using rational engineering methods. Besides, automation of ALE technology could be even a better strategy to make the evolution process of desired phenotype and product development process selective and time efficient. However, unavailability of selection pressure for some valuable phenotypes limits the widespread application of ALE for some phenotypes. 

Graphical Abstract