eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2017-03-25 14 1 63 68 10.13005/bbra/2417 17842 article Mohammad Javad Kazemi 1 Mohammad Kargar 2 Jamileh Nowroozi 1 Abbas Akhavan Sepahi 1 Abbas Doosti 3 Zahra Manafi 4 Department of Microbiology, Tehran North Branch, Islamic Azad University, Tehran, IR Iran. Department of Microbiology, Jahrom Branch, Islamic Azad University, Jahrom, IR Iran. Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA. National Iranian Copper Industries Co. Sarcheshmeh Mine, IR Iran. One of the problems with thermoacidophilic microorganisms is purifying them through solid media and that’s why purifying them in most cases has been done using serial dilution. Basal salts and solidification agents used in media have an important role in growing microorganisms. The purpose of this study was preparing the solidified medium with GELRITE and Starch for isolating and purifying indigenous thermoacidophilic microorganisms from Sarcheshmeh Copper Complex in Iran. We used various methods in this study to prepare and optimize GELRITE medium for thermoacidophilic microorganisms. The best method is as follows: GELRITE was separately dissolved in 40 ml of distilled water. The bottle of GELRITE was placed on magnetic stirrer at 90ºC and a magnet was placed in it to stir. The magnet was agitated at 520 rpm for 40 minutes to cause the solution appear dispersed, homogeneous and clear. Various methods were also applied to prepare starch as a solidification factor to culture this group of microorganisms which none succeeded. GELRITE was clear after preparing, and after one month a lot of tiny colonies were observed on GELRITE plates. The first colonies appeared during the first week. When the colonies were removed using a loop -since the colonies were so tiny- the solidified medium was removed, too. Industrializing the thermophilic microorganisms has always encountered difficulties due to culturing insufficiencies and hardness. A confident method for culturing thermoacidophilic microorganisms on a solidified medium with GELRITE and how to keep the plates at the temperature of 70ºC is introduced in this study. This method allows both preparing the solid medium for culturing thermoacidophilic microorganisms and keeping it for a long time (1 month or more) at 70ºC or even higher. https://www.biotech-asia.org/vol14no1/optimization-and-comparison-of-different-procedures-of-preparation-gelrite-and-starch-as-solidifying-agents-for-culturing-indigenous-thermoacidophilc-microorganisms-and-how-to-keep-them-at-the-tempera/ GELRITE; Starch; Iran microorganisms; thermoacidophilic