Integrated System of Microalgae Photobioreactor and Wine Fermenter: Growth Kinetics for Sustainable CO2 Biocapture

Abstract

Microalgae possess the remarkable ability to autotrophically grow, utilizing atmospheric carbon dioxide (CO2) for photosynthesis, thereby converting solar energy into chemical energy and releasing oxygen. This capacity makes them an effective tool for mitigating industrial CO2 emissions. Mathematical models are crucial for predicting microalgal growth kinetics and thus assessing their potential as industrial CO2 sequestration agents under controlled conditions. This study innovatively evaluated the effect of continuously supplying CO2 from winemaking processes on microalgal cultivation and biomass production, demonstrating a novel approach to both carbon capture and the valorization of a valuable by-product. To analyze microalgal growth kinetics, three mathematical models were employed: Logistic, First Order Plus Dead Time, and Second Order Plus Dead Time. Optimal parameter values for each model were identified using a hybrid search algorithm developed by our research group. First, an integrated microvinification system was established, utilizing two microalgae species, Chlorella spp. (FAUBA-17) and Desmodesmus spinosus (FAUBA-4), in conjunction with yeast fermenters. This system facilitated a comparison of the biomass kinetics of these two microalgae species, selecting Chlorella spp. (FAUBA-17) as the most suitable candidate for subsequent cultivation. A pilot-scale vertical column photobioreactor was then constructed and installed at the Casimiro Wines boutique winery in Angaco, San Juan, Argentina. After 15 days of operation within the photobioreactor, a biomass growth of 1.04 ± 0.05 g/L and 1.07 ± 0.1 g/L was obtained in Photobioreactors 1 and 2, respectively. This novel integrated approach to CO2 capture in the winemaking process is unprecedented. These findings highlight the potential for producing high-value microalgal biomass, promoting the establishment of a local biorefinery and fostering a circular economy and sustainable social development.