Microalgae from wastewaters to wastelands: Leveraging microalgal research conducive to achieve the UN Sustainable Development Goals

The scientific evidence on applications of microalgae in bioremediation of wastewaters, increasing agricultural productivity, and biomass production strengthens their potential in supporting global socio-economic and environmental sustainability. Microalgae can consume organic compounds and pollutants present in domestic, agricultural, and industrial wastewater. This leads to biomass production in wastewater and water being relatively safe to be disposed of into water bodies and safeguard life in water. The extensive diversity of microalgae, encompassing a distinct array of physiological, reproductive, and functional traits, along with their remarkable efficiency in wastewater treatment, positions this group of organisms as exceptionally superior to other organisms. Molecular and biotechnological approaches have provided promising tools for improving the biomass production of microalgae from wastewater. Recent technological innovations have facilitated harvesting algal biomass from wastewater treatment plants for developing a range of bioproducts like bioenergy, biofertilizer and other various high value biochemicals. Microalgal communities and their biomass produced from wastewater are investigated for the restoration of degraded lands. The potential use of diverse microalgal species and their biomass from wastewater for restoration of degraded lands such as salt-affected lands, drought ridden arid areas, fly ash contaminated lands, and metal-polluted mine spoils is discussed. Moreover, this review elaborates on how use of microalgae from wastewater to wastelands can contribute to various sustainable development goals (SDGs). It is found that extending microalgae research and use from wastewater to wastelands can support achieving all SDGs by directly contributing to 10 goals.