Investigation of gold content in the bio-oxidation process Tulkin Nurmurodov, Nodira Saidova, Oybek Ashurov, Gulrukh Rakhimova, Omon Fuzaylov and Jakhongir Narzullaev E3S Web Conf., 417 (2023) 02011 Published online: 21 August 2023 DOI: 10.1051/e3sconf/202341702011