Microalgae-derived biolubricants: Challenges and opportunities
Duong T Nguyen, Md Abu Hasan Johir, T.M.I. Mahlia, A.S. Silitonga, Xiaolei Zhang, Qiang Liu, Long D. Nghiem
Abstract
Lubricants are indispensable in the modern economy for controlling friction and wear across many industries. Traditional lubricants are derived from petroleum crude and can cause significant ecological impact if released into the environment. Microalgae have emerged as a potential alternative to petroleum crude for producing renewable and environmentally friendly biolubricants. This review systematically assesses recent developments in microalgal-based biolubricant production, including tribological performance, microalgae selection, cultivation, harvesting, lipid and polysaccharide extraction and conversion to biolubricants, and market development. Compared to petroleum-based lubricants in terms of tribological properties, biolubricants are compatible with most emerging applications, such as electric vehicles and wind turbines. Nevertheless, they are less thermally and chemically stable, thus, may not be suitable for some traditional applications such as internal combustion engines. Literature data corroborated in this study reveals an urgent need for further research to scale up microalgae production and lower the cost of biomass harvesting. While technologies for converting microalgae-derived lipids to biolubricants appear to be well established, additional work is necessary to also utilize polysaccharides as another key ingredient for producing biolubricants, especially for low-temperature applications. Extraction methods are well established but further research is also needed to reduce the ecological impact, especially to utilize green solvents and reduce solvent consumption. Additionally, future research should delve into the use of nanoparticles as effective additives to obtain microalgae-based biolubricants with superior properties. Finally, it is essential to standardize the labeling system of biolubricants to establish a global market. • Microalgae-derived biolubricants are attractive for new and emerging applications. • Production scale and harvesting cost must be overcome for commercial realisation. • Technologies are available to extract lipid and convert to biolubricants at scale. • Polysaccharide biolubricants have significant and unexplored potential. • International standard for biolubricant labeling is vital for market development.