Preliminary evaluation on interaction between Galdieria sulphuraria and chrysotile

Asbestos, a naturally occurring fibrous silicate, was extensively utilized in construction between 1965 and 1987 due to its fire-retardant, sound-absorbing, electrical insulating, and heat-resistant properties, as well as its mechanical flexibility. By the 1990s, the deleterious health effects of airborne asbestos fibers became evident, ranging from asbestosis to mesothelioma, prompting widespread bans on its mining and use internationally. Despite extensive efforts to identify and secure asbestos-containing materials in buildings, a significant challenge persists: the safe disposal of deteriorating materials, which must adhere to stringent regulatory safety standards. This paper presents preliminary findings on utilizing Galdieria sulphuraria, a multi-extremophilic red microalga, for the phycoremediation of chrysotile asbestos. This specific microorganism was selected for its remarkable ability to maintain intracellular homeostasis under extreme conditions (pH 0–4, temperatures up to 56 °C) and its established feasibility for industrial-scale cultivation, making it particularly suitable for integration into waste management protocols. Multiple experimental iterations consistently demonstrated chrysotile degradation under varying conditions. To quantify magnesium removal from asbestos fibers, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) was employed. Concurrently, inductively coupled plasma optical emission spectrometry (ICP-OES) detected solubilized magnesium in the liquid phase, with concentrations increasing progressively over a two-week period. Results demonstrate significant alterations in chrysotile's optical properties, morphological characteristics, and structural composition, particularly the removal of its outer brucitic layer, verified through phase contrast optical microscopy (PCOM) and X-ray powder diffraction (XRPD). This biological approach offers a promising alternative to conventional physicochemical treatments, operating efficiently at ambient temperatures while minimizing secondary waste generation.