Recent challenges in biological cyanidation and oxidation of sulfide-based refractory gold ore

In mining industries, biomining (comprising biooxidation and bioleaching) is implemented to extract metals from specific ores and waste streams with less environmental effect and expense. Usually, micron-sized gold particles are held in a crystal lattice of iron sulfide minerals and expensively extracted using common approaches. Researchers and industries are interested in developing recent technology and biologically sustainable methods in both pretreatment and further extraction steps for extracting this valuable metal from ores. Diverse studies in biooxidation, as a conventional pretreatment, and biocyanidation, as a new proposed biotechnological method in the downstream gold extraction step, have addressed scientific and technological issues in the extraction of this metal. These two methods have become economically practical by merging high-throughput microbiological data, extraction and recovery process knowledge, and theory validation. However, there is still a gap in the implementation of both the pretreatment method and extraction method due to the consistency and their compatibility with operational recovery conditions. This review brings out the recent biooxidation and biocyanidation improvements, innovation, industry and academic research, and obstacles to gold extraction with a brief explanation to address the recent developments.