sentences:  This process is used by some bacteria to synthesise carbon compounds, sometimes using hydrogen, sulfide, or thiosulfate as electron donors.In this process, it can be seen as an alternative to the fixation of inorganic carbon in the reductive pentose phosphate cycle which occurs in a wide variety of microbes and higher organisms.The reaction is a possible candidate for prebiotic early-earth conditions and, so, is of interest in the research of the origin of life.