Abstract: Gold ions are removed from aqueous solution or suspension by treatment of aqueous material with biomass derived from the genus Sargassum (e.g.: Sargassum natans), a brown sea-water alga. The process can be utilized to remove gold from industrial or natural waters.

Abstract: Uranium or thorium cations are removed from aqueous suspension or solution by treatment of the aqueous material with the biomass derived from fermentation of a fungal microorganism of the genus Rhizopus, e.g. Rhizopus arrhizus. The process can be utilized to treat aqueous tailings from uranium ore extraction processes, to reduce the radioactive content of the tailings prior to disposal.

Abstract: A new process for cultivating selected cultures involves initially removing broth at a first rate from a fermentation and replacing it with supporting medium, the replacement rate thereafter being increased to remove cultures of lower growth rate than the selected culture. A new process for the microbiological synthesis of protein-containing material by an aerobic fermentation in a supporting medium uses a normally gaseous hydrocarbon substrate selected from nethane, ethane, propane and butane and a protein-producing fungus of graphium species. It has not been known hitherto for such syntheses to be possible with a fungus. The said substrate may be natural gas.