A new circular alliance between wine and microalgae is created in Argentina

A study highlights how CO2 recovered from the fermentation process can be used to stimulate the growth of microalgae. Benefiting the climate and the development of bioproducts

by Matteo Cavallito

 

CO2 produced in the wine fermentation process can be successfully used to grow microalgae. A circular bioeconomy strategy that contributes to “to both carbon capture and the valorization of a valuable by-product.” This is supported by a study involving several researchers from the Universidad Nacional de San Juan and the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) in Buenos Aires.

The investigation, published in the journal Fermentation, thus brings additional knowledge on the topic of the potential of algae starting with their aptitude for carbon sequestration. Which, the authors recall, makes these plants “an effective tool for mitigating greenhouse gas emissions, particularly when cultivated on non-fertile lands using photobioreactors.”

The benefits of microalgae

Unlike typical large seaweeds, microalgae are a diverse collection of unicellular photosynthetic organisms that can grow rapidly in fresh or salt water under photoautotrophic conditions. “Notably,” the study explains, ”microalgae can capture substantial amounts of CO2, fixing 10 to 50 times more CO2 than terrestrial plants while producing an average of 1.83 g of biomass per gram of CO2 consumed.” Moreover, they “contribute to bioremediation by effectively retaining heavy metals and other pollutants.”

Finally, their biomass is rich in proteins and antioxidants and “offers a valuable resource for various applications, including biofertilizer, biofuels, food production, and pharmaceuticals.”

According to the researchers, these characteristics can be harnessed to produce benefits in a production sector still responsible for a significant carbon footprint: the wine industry. “In San Juan, Argentina, the winemaking industry plays an important role in the regional economy,” the study notes. “However, the industry faces significant challenges in reducing its carbon footprint, as it is both energy-intensive and heavily reliant on conventional practices that contribute to global CO2 emissions.” And that’s where algae come in.

CO2 from fermentation makes algae grow.

The study thus explores the potential of an integrated system that combines a microalgae photobioreactor with a wine fermenter to capture CO₂ produced and used by plants. The researchers first tested two species of microalgae (Chlorella spp. and Desmodesmus spinosus) in the laboratory, verifying their ability to grow. Then they installed a photobioreactor in the cellar of a winery (Casimiro Wines in San Juan, Argentina) by connecting it to a 150-liter fermenter of must.

During the fermentation of the must, 7,840 g of CO₂ was produced. Carbon dioxide was then piped into two photobioreactors. At the end of the 15-day experiment, the growth of microalgae in the photobioreactors reached 1.04 and 1.07 grams of biomass per liter, respectively. The data show that the system absorbed a significant portion of the emitted CO₂ by transforming it into microalgal mass.

A viable circular solution

In short, the study shows how integrating microalgae with winemaking can help reduce the environmental impact of the industry. It also creates new opportunities to exploit the potential of microalgae in different sectors. “The integration of microalgae cultivation and winemaking presents a compelling solution due to its ability to transform CO₂ emissions into valuable biomass, aligning with the principles of a circular economy,” the researchers say.

In addition, “the biomass produced can generate high-value products such as biofertilizers, pigments, and food supplements, diversifying revenue streams for wineries.” Which, by adopting this strategy, “can significantly reduce their carbon footprint, improve their competitiveness in sustainability-conscious markets, and contribute to global efforts against climate change.”