Mariana R. Corona-Ramírez

The Santiago River near the Guadalajara Metropolitan Area is one of the most contaminated water bodies in Mexico, where heavy metals pose a major threat to aquatic ecosystems. Chronic metal pollution has promoted the adaptation of native microbial communities, including the production of metal-chelating metabolites such as siderophores, which represent a valuable resource for remediation-oriented biomaterials. In this study, bacterial strains were isolated from water and sediment samples, then screened for siderophore production using the Chrome Azurol S assay (CAS), complemented by a MATLAB-based image processing approach for semi-quantitative ranking prior to taxonomic identification by MALDI-TOF MS. Based on biosafety considerations and cultivation robustness, Bacillus thuringiensis was selected as a benchmark case, being immobilized onto activated carbon to produce a carbon–bacteria biocomposite (CBM). To evaluate the performance of CBM, Cu(II) was used as a model contaminant due to its industrial relevance, persistence, toxicity, and strong complexation behavior. Batch adsorption experiments showed that the CBM exhibited a 23.9% higher maximum Cu(II) sorption capacity than pristine activated carbon. Acute toxicity assays using Vibrio fischeri further indicated reduced toxicity in CBM-treated effluents, supporting the feasibility of this contained biocomposite for heavy metal remediation.

A sustainable strategy is proposed for the valorization of solid waste from the Tequila industry through the development of bio-packaging for Tequila bottles using mycelium from Ganoderma lucidum. The fungus was isolated from Bosque de la Primavera (Jalisco, Mexico) and cultivated on lignocellulosic substrates: agave bagasse and corn stover. These agricultural residues were dried, ground, and pasteurized to optimize their performance as growth media. Their structural integration before and after fermentation was evaluated using optical microscopy. The high cellulose and hemicellulose content of both substrates supported robust mycelial development, enabling the formation of moldable materials through solid-state fermentation. After growth, the mycelium colonized the substrate, forming a functional mold adapted to the geometry of a Tequila bottle prototype. The molded parts were dried to halt fungal activity, prevent fruiting, and stabilize the structure. Physical and mechanical characterization showed competitive performance with regard to bulk density (0.11 ± 0.1 g cm⁻³), water absorption (78.1 ± 4.2%), and high impact resistance (evaluated via Solidworks simulation). A life cycle assessment revealed that mycelium packaging has a significantly lower environmental impact than expanded polystyrene. The material supports circular economy principles within the Tequila production chain.