LAUSR

Abstract Microorganisms actively participate in biogeochemical cycles of various elements in the environment, including gold. To explore the core microbiota associated with gold ore, this study examined the bacterial composition of mined rock from the Rozália gold mine (two subsurface samples from the gold mine and one from the heap of mined ore) using a cultivation approach. Cultivation analyses showed the occurrence of bacteria with colony forming units (CFU) ranging from 2.18 × 105 to 3.16 × 105 per 1 gram of dry ore material, and the data analysis indicates that the type of cultivation medium used significantly influences the observed biodiversity of cultivable bacteria. Cultivated members of the microbial community were identified using a combination of MALDI-TOF MS and 16S rRNA gene sequencing. The cultivable microbiota of gold-bearing ore samples was predominantly composed of the phylum Proteobacteria. Identification of 473 isolates revealed the presence of 4 dominant genera: Rhizobium, Microbacterium, Pseudomonas, and Acinetobacter, which together accounted for 89% of the gold ore-associated cultivated bacteria. These results are consistent with previous studies on the microbiota of gold mines and suggest that these genera constitute the core microbiota of gold ore.