Chitin Polymer Transformation Driven by Particulate Matter and Biofilm Interaction in a Disturbed Estuarine Environment

Abstract

Chitin is critical in carbon and nitrogen recycling, facilitates pollutant adsorption and serves as a substrate for potentially pathogenic microorganisms. This study evaluated its structural, chemical, and microbiological transformations in a polluted environment. An experiment was conducted in the Bahía Blanca Estuary, using chitin in devices attached to a buoy, where samples were collected after 21 and 36 days. X-Ray Diffraction revealed reduced crystallinity over time, with diminished intensity and sharpness of characteristic peaks. Fourier Transform Infrared Spectroscopy detected spectral changes after 36 days, including reduced amide I and II peaks sharpness, indicating partial degradation, via hydrolytic and oxidative processes. Hydroxyl and phosphate groups potentially linked to biofilm formation were also identified. Scanning electron microscopy revealed gradual surface deterioration with cracks and pores and the accumulation of organic and inorganic aggregates, including diatoms. Energy Dispersive X-ray confirmed the presence of heavy metals including molybdenum and iron, likely associated with suspended particulate matter adhering to chitin surface. Fungal and coliform counts increased significantly after 36 days, while heterotrophic bacteria levels remained constant. Vibrio spp. was also detected. Overall, this study underscores chitin´s dual role in biogeochemical processes and environmental applications. As a key component in biodegradation, biofilms facilitate its transformation, highlighting its function as a heavy metal chelating agent and a carbon and nitrogen source. Additionally, the findings suggest the potential of chitin for water treatment applications, where its interactions with biological and environmental factors could be leveraged, providing valuable scientific insights at local and global scales.