Parshina Victoria V. RussiaSaratov State University , 83, Astrakhanskaya str., Saratov, 410012, Russia parshina-v-v@yandex.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