A Novel System for Real-Time, In Situ Monitoring of CO ₂ Sequestration in Photoautotrophic Biofilms

Abstract

Climate change brought about by anthropogenic CO ₂ emissions has created a critical need for effective CO ₂ management solutions. Microalgae are well suited to contribute to efforts aimed at addressing this challenge, given their ability to rapidly sequester CO ₂ coupled with the commercial value of their biomass. Recently, microalgal biofilms have garnered significant attention over the more conventional suspended algal growth systems, since they allow for easier and cheaper biomass harvesting, among other key benefits. However, the path to cost-effectiveness and scaling up is hindered by a need for new tools and methodologies which can help evaluate, and in turn optimize, algal biofilm growth. Presented here is a novel system which facilitates the real-time in situ monitoring of algal biofilm CO ₂ sequestration. Utilizing a CO ₂-permeable membrane and a tube-within-a-tube design, the CO ₂ sequestration monitoring system (CSMS) was able to reliably detect slight changes in algal biofilm CO ₂ uptake brought about by light–dark cycling, light intensity shifts, and varying amounts of phototrophic biomass. This work presents an approach to advance our understanding of carbon flux in algal biofilms, and a base for potentially useful innovations to optimize, and eventually realize, algae biofilm-based CO ₂ sequestration.