Increased biomass and biomolecule productivity of Spirulina sp. LEB 18 cultivated with CO₂ adsorbent nanofibers

CO₂ remediation is an urgent and challenging task to mitigate global climate change. Microalgae efficiently convert CO₂ into biomass, offering potential for the development of bioproducts such as biofuels. Polyacrylonitrile (PAN) nanofibers, due to their porous structure and high surface area, can be integrated into microalgae cultivations to enhance CO₂ capture. The adsorption performance of these nanofibers can be enhanced by incorporating compounds like monoethanolamine (MEA), and industrial CO₂ chemical absorbent, which modifies the nitrogenous structures of the polymer to favor CO₂ adsorption. This study aimed to produce PAN nanofibers with MEA for use in Spirulina sp. LEB 18 cultivation to asses microalgae growth and biomass composition. Uniform nanofibers with a mean diameter of 768 nm were developed with 1% of MEA and utilized in microalga grown. The highest CO₂ biofixation rate and biomass productivity were achieved in cultivations with nanofibers without MEA (327.6 mg L⁻¹ d⁻¹ and 178.7 mg L⁻¹ d⁻¹, respectively). Biomass obtained in cultivations with nanofibers showed increased lipid (76.6 mg L⁻¹ d⁻¹) and protein (404 mg L⁻¹ d⁻¹) productivity, 2.1 and 1.7 higher, respectively, than the assay without nanofibers. Thus, PAN nanofibers act as CO₂ adsorbents, enhancing gas biofixation by Spirulina sp. LEB 18, contributing to biomass production and increasing proteins and lipids yields.