Microalgae bioremediation: A perspective towards wastewater treatment along with industrial carotenoids production

Carotenoids are natural pigments known for their various health benefits for humans together with various other applications in diverse industries. Considering the high market value of carotenoids in the food and health sector, sustainable production of these metabolites for commercial applications is the need of time. Among various microbial alternatives, microalgae are considered as a rich source of carotenoids along with other metabolites and received special attention. However, commercial microalgae production is not fully developed and diversity of data is available regarding the cost-effectiveness of algal biomass production. Recent studies employing novel technologies and methods, coupled with the utilization of wastewater for algal cultivation are providing an innovative way forward. Implementation of wastewater for the cultivation of microalgae offers an economical, sustainable, and environmentally friendly method of resource utilization and urban wastewater management. This review intends to highlight the potential of microalgae species using wastewater for the production of different categories of carotenoids. The review will discuss the integrated approach that can be implemented for the biosynthesis of these value-added products along with wastewater treatment. Different techniques and factors which can be utilized for the upstreaming and downstreaming of the algal carotenoids will also be addressed in detail along with their challenges. Possible recommendations for the coupling of microalgae with wastewater as an effective method of waste remediation and as a source of potential products are also proposed.