Blended wastewater as a source of nutrients and biosynthetic elicitors for microalgal biorefinery

Growing environmental constraints on resources necessitates finding renewable and sustainable means of production. Microalgae provides a promising resource for feedstock in many bio-products and for waste utilisation. Microalgae contain a variety of high-value products and are known for their bio-synthesis from waste sources. Increased industrial operations become a sustainable source of wastewater containing nutrient loads; in parallel, energy expenditures imparted to wastewater reclamation deteriorate the environment. To balance this, a circular economy that creates benefits to the environment and increases industrial productivity through planning out pollution/waste and recycling waste and materials back into use is essential. For example, various chemicals in wastewater can be used as sources of nutrient and bio-synthetic inducers in algal biorefining. This review discusses the required technical developments and knowledge gaps across multiple reuse methods for wastewater resources that support public health, industry, and environmental regulatory policies. Furthermore, this review surveys how industrial wastewater can serve as a sustainable resource, with chemical contents as a source of nutrient and substrate for algal cultivation and strategies necessary for biorefinery methods. Wastewaters have noxious contents, but various algal traits are relatively tolerant towards mixed chemicals, in some cases influencing biosynthetic pathways. The chemistry of wastewater varies depending on the stages and processes involved in product manufacturing, this variation require careful planning to ensure that the contents of the wastewater align with the specific targeted uses as a source of micro and macronutrients.