Dyatlova Yulia A. RussiaInstitute of Biochemistry and Physiology of Plants and Microorganisms of the Russian Academy of Sciences, 410049, Russia, Saratov, Entuziastov Avenue, 13tugarova_anna@mail.ru Author's articles Fourier Transform Infrared Spectroscopic Analysis of Poly-3-Hydroxybutyrate Accumulation by Azospirillum brasilense Cells at Various Cultivation Periods and Ammonium Concentrations in the Culture Medium