Azospirillum Medium w/o Agar (Twin Pack) is recommended for cultivation of Azospirillum species. This medium contains malic acid which serves as the prime carbon source. Azospirillum species grow well in presence of malic acid and are not overgrown by other nitrogen fixers. Necessary trace elements like ferrous sulphate, manganese sulphate, sodium molybdate supports growth of Azospirillum species.