Comparison of microfluidic and traditional methods for separation of Antarctic microalgae cells and life cycle assessment

Abstract

Antarctica hosts a diverse range of microorganisms, such as microalgae, bacteria, fungi, and amoebas, that have evolved remarkable biochemical adaptations to endure extreme environmental conditions. Efficiently isolating polar microalgae from natural samples is still technically demanding, resulting in a need for innovative and rapid isolation techniques. To address this need, in this study, microfluidic platforms with curvilinear, spiral and multistage (spiral-curvilinear) microchannel configurations were designed and developed to enable effective separation of Antarctic microalgae. This approach was compared with conventional antibiotic treatment approach both experimentally and with life cycle assessment (LCA). The tests on the separation performance for spiral microchannel configurations resulted in a maximum efficiency of 89 %, while curvilinear and multi-stage configurations achieved efficiencies of 76 % and 56 %, respectively. Separation purity exceeded 85 % in all microfluidic experimental sets. Antibiotic treatment had a 27 % separation efficiency in the first 5 days, while the efficiency reached 100 % at the end of 15 days. Growth kinetics results following the different separation approaches indicated that microfluidic treatment enhanced cell growth compared to the control, whereas antibiotic treatment initially suppressed growth but promoted it at later stages. LCA also revealed that microfluidic separation resulted in lower environmental impacts compared to antibiotic-based protocols. These findings highlight the potential of optimized microfluidic systems as rapid, environmentally friendly and non-destructive tools for microalgae purification.