Sulfur reduction biotechnology has been in use in in mining streams to assist in the recovery of metals as sulfides. Present in many naturally occurring streams, sulfate is biologically reduced to sulfide using ethanol or hydrogen as electron donor. Sulfate precursed processes for sulfide production have been object of extensive research in the last years, shading other conceivable routes such as the elemental sulfur reduction which could improve the feasibility of a sulfide metal recovery economy. Stoichiometrically, the elemental sulfur reduction yields a 4-fold decrease of the electron donor consumption of the process compared to the sulfate processes. This is equivalent a reduction of approximately 40-50% of the operational costs. Furthermore, sulfate reduction is not fully compatible with mining streams as its reduction is primarly possible at circumneutral pH and mesophilic temperature. Thus, this research proposes to investigate the bioreduction of elemental sulfur under mining stream conditions of low pH (2-4) and thermophilic (70-80 C) and mesophilic (20-30 C) temperature combined. The target of this research is to achieve an specialized process for the precipitation of insoluble metal sulfides on hot acidic streams.