Bio-coatings as immobilized microalgae cultivation enhancement: A review

• Published in: The Science of the total environment Vol. 887; p. 163857
• Main Authors: Tong, C.Y., Derek, C.J.C.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.08.2023
• Subjects: Attached culture; Biofilm; Biofuels; Biomass; Environmental biotechnologies; Harvesting; Latex; Microalgae; Microalgal growth improvement; Wastewater; Water; Biofilm; Attached culture; Environmental biotechnologies; Harvesting; Microalgal growth improvement
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.163857

Bio-coatings serve as artificial scaffolds for immobilizing microalgae to facilitate cell concentration and harvesting. It has been used as an additional step to enhance the natural microalgal biofilm cultivation and to promote new opportunities in artificially-immobilize cultivation technology of microalgae. This technique is able to enhance biomass productivities, enable energy and cost saving, water volume reduction and ease of biomass harvesting since the cells are physically isolated from the liquid medium. However, scientific discoveries of bio-coatings for process intensification are still lacking and their working principles remained unclear. Therefore, this critical review aims to shed light on the advancement of cell encapsulation systems (hydrogel coating, artificial leaf, bio-catalytic latex coating, and cellular polymeric coating) over the years and aid in the selection of appropriate bio-coating techniques for various applications. Discussion on the different preparation routes of bio-coatings, as well as the exploration towards the potential of bio-based coating materials such as natural/synthetic polymers, latex binders, and algal organic matters are also included, with a focus on sustainable pursuits. This review also presents in-depth investigations into the environmental applications of bio-coatings in wastewater remediation, air purification, carbon bio-fixation, and bio-electricity. The field of bio-coating in microalgae immobilization gives rise to a new ecofriendly strategy with scalable cultivation footprint and a balanced environmental risk aligning with the United Nation's Sustainable Development Goals with potential towards the contribution of Zero Hunger, Clean Water and Sanitation, Affordable and Clean Energy, and Responsible Consumption and Production. [Display omitted] •Bio-coatings enhance microalgal biofilm cultivation systems on any supports.•Adhesive bio-coatings could be fabricated in either particulate or layered forms.•Microalgae cultivated within natural or artificial bio-coatings exhibit longevity.•Bio-coatings deposition is flexible depending on the target of interest.•Emerging bio-coatings allow broad range of biotechnological applications.