Environmental and Economic Sustainability of Algal Lipid Extractions: An Essential Approach for the Commercialization of Algal Biofuels

The concept of algal fuels is almost half a century old. Although the idea of this seemingly ‘carbon neutral’ green fuel from a renewable resource was received with considerable interest, the technology posed severe economic challenges. Therefore, commercialization of algal fuels has not yet been achieved. However, rising petroleum prices make it worthwhile to focus on algal lipids to meet energy demands. Some of the major impediments to the commercialization of algal fuel—such as ecological, economic and social limitations, are observed. The extraction of lipids from the biomass, among other downstream processes, contributes significantly to the cost of production. It is also a key factor that determines the quality of oil produced and the efficacy of the process, which, in turn significantly affects its economy. Various methods of extraction, their scalability and process economy, toxicity and reusability of solvents, their ill-effects on any co-products and impact on the environment will be compared. The technology has now raised concerns regarding the carbon footprint, energy consumption and the overall sustainability of the method. The use of sustainability assessments to account for ecological and economic constraints is a relatively less developed area and is discussed. A comprehensive analysis of the environmental and economic sustainability of algal lipid extractions is expected to help identify measures to improve the scope for commercialization of algal biofuels.