The biogeochemical cycling of gold has been proposed from studies focusing on gold particle morphology, surface textures and associated bacteria living on the surface of gold particles. Additionally, it has been suggested that metabolically active bacteria on particles catalyse gold dissolution and gold re-precipitation processes, i.e. fluid–bacterial–mineral interaction within microenvironments surrounding particles. Therefore, the isolation and characterisation of viable bacteria from gold particles can be used as a model to improve the understanding of bacterial–gold interactions. In this study, classical microbiology methods were used to isolate a gold-tolerant bacterium (Acinetobacter sp. SK-43) directly from gold particles. The genome of this isolate contained diverse (laterally acquired) heavy-metal resistance genes and stress tolerance genes, suggesting that gene expression would confer resistance to a wide range of potentially toxic metals that could occur in the surrounding microenvironment. The presence of these genes, along with genes for nutrient cycling under nutrient-limited conditions highlights the genomic capacity of how Acinetobacter sp. SK-43 could survive on gold particles and remain viable. Laboratory experiments demonstrated that this isolate could grow in the presence of soluble gold up to 20 μM (AuCl3) and that >50% of soluble gold was reduced upon exposure. Collectively, these results suggest that Acinetobacter sp. SK-43 (and presumably similar bacteria) could survive the cytotoxic effects of soluble Au from particles undergoing dissolution. This study provides comprehensive insight on the possible bacterial contributions to gold biogeochemical cycling in natural environments.

黄金的生物地球化学循环已经从研究集中在金颗粒的形态，表面纹理和生活在金颗粒表面上的相关细菌的研究中提出。此外，有人提出，颗粒上具有代谢活性的细菌会催化金的溶解和金的再沉淀过程，即颗粒周围微环境中的流体-细菌-矿物质相互作用。因此，从金颗粒中分离和鉴定活细菌可以用作提高对细菌-金相互作用的理解的模型。在这项研究中，经典的微生物学方法被用于分离耐金细菌（不动杆菌sp。SK-43）直接从金颗粒中提取。该分离物的基因组包含不同的（侧向获得的）重金属抗性基因和胁迫耐受性基因，这表明基因表达将赋予周围微环境中可能发生的多种潜在有毒金属抗性。这些基因的存在，以及在营养有限的条件下进行营养循环的基因，突出了不动杆菌属的基因组能力。SK-43可以在金颗粒上存活并保持活力。实验室实验表明，这种分离物可以在存在高达20μM（AuCl 3）的可溶性金的情况下生长，并且暴露后> 50％的可溶性金会减少。总的来说，这些结果表明不动杆菌sp。SK-43（和大概相似的细菌）可以抵抗可溶性金从溶解颗粒中产生的细胞毒性作用。这项研究提供了对自然环境中细菌对金生物地球化学循环的可能贡献的全面见解。