activities. Growth and metabolic activity were observed exclusively at 30 and 45 °C, while no microbial activity was detected at 55 °C. Out of 11 samples analyzed, six exhibited metabolic activity compatible with biomining processes. Based on these results, two consortia were selected for further biohydrometallurgical experimentation: Kobold A (30 °C) and Kobold B (S) DSM 35389 (45 °C), (henceforth referred to as Kobold B). Additionally, cell viability assays were performed for these consortia under optimal growth conditions and in the presence of "Cola Scavenger" mineral residues. 2.2.Taxonomic characterization Taxonomic characterization of both consortia was performed by 16S rRNA gene sequencing, using the 16S Barcoding Kit 1-24 (SQK-16S024) protocol and the Oxford Nanopore Technologies (ONT) platform. 2.3.Sampling and characterization of mineral residue Two independent sampling campaigns were conducted to obtain the "Cola Scavenger" fraction from the cleaning circuit (CS-CL) at the San José de Pucobre flotation plant. In the first campaign, 60 kg of material were collected and processed via quartering, primary and secondary crushing, and subsequent dry homogenization. For the second campaign, 150 kg of fresh sample were obtained and subjected to the same preparation protocol. Cobalt concentrations were determined using atomic absorption spectroscopy (AAS). 2.4.Mineralogical and granulometric characterization Mineralogical characterization of both CS-CL sample batches was conducted using TESCAN Integrated Mineral Analyzer (TIMA) software, supplemented by X-ray Diffraction (XRD) analysis for the initial batch. These analyses were performed to quantify the abundance of sulfide phases and gangue minerals, as well as to determine the degree of target mineral liberation. The granulometric profile of both batches was established by quantifying the distribution of valuable species within individual mineral particles. Particles were binned according to their valuable species content into 10% class intervals, spanning from <10% to ≥90%, and these classes were subsequently used to evaluate the particle size distribution. 2.5.Biohydrometallurgical tests in flasks As a preliminary stage, bioleaching tests were performed in flasks, using 0,5X KMD medium supplemented with Fe(II) and a pulp concentration of 20% (w/w) of Cola Scavenger. A total of six flasks were evaluated under conditions with and without microbial inoculation: M1 (uninoculated, 30 °C), M2–M3 (inoculated with Kobold A, 30 °C), M4 (uninoculated, 45 °C), and M5–M6 (inoculated with Kobold B, 45 °C). The experiments were conducted under agitation and temperature control, pH, Eh (redox potential with Ag/AgCl electrode) and Cobalt recovery was systematically monitored throughout the duration of the test. 2.6.Bioleaching tests in minicolumns
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