VALORIZATION OF MICROALGAE IN WASTEWATER TREATMENT AND BIODIESEL PRODUCTION.

Micro and macroalgae are renewable and carbon-neutral sources of energy that can grow naturally or can be cultivated in nutrient-rich wastewater, without compromising the production of food crops. Microalgae use nutrients, accumulate heavy metals and reduce coliform bacteria from wastewater, thus contributing to their phytoremediation. Furthermore, the conversion of algae biomass into biofuels contributes to reducing the dependence on fossil fuels and greenhouse gas emissions in the atmosphere. Depending on the species and cultivation method, microalgae have a very fast growth rate (12 days) and their potential to produce biodiesel is 15 to 300 times higher than that of agricultural and energy crops conventionally used for biofuels. Lipid content in microalgae can reach 75-80% by weight of dry biomass. To produce 39 billion liters of biodiesel, 15 million tons of nitrogen and 2 million tons of phosphorus are required during the growth process of microalgae. From algae cultivated in 500 billion m3 of industrial wastewater, approximately 37 million tons of oil can be extracted that can be transformed into biodiesel. However, there are also challenges in large-scale utilization of microalgae, due to the high energy input, technical difficulties encountered in harvesting unicellular microalgae, and the need for subsequent pretreatment operations to improve lipid extraction. This paper reviews the potential of microalgae species to thrive in wastewater and the technological achievements in converting microalgae biomass for the sustainable biodiesel production. [ABSTRACT FROM AUTHOR]