EFFECT OF COMPLEX NITROGEN-SOURCES ON PULLULAN PRODUCTION RELATIVE TOCARBON SOURCE

The effect of complex nitrogen sources, including tryptone, peptone, s oytone, casamino acids and corn steep liquor, on pullulan production b y Aureobasidium pullulans ATCC 42023 was studied in a medium where suc rose or corn syrup served as the carbon source. Growth on soytone resu lted in the highest level of pullulan production by ATCC 42023 indepen dent of the carbon source utilized. In general, all the complex nitrog en sources examined increased pullulan production relative to ammonium sulphate for either sucrose- or corn syrup-grown cells. Cell weights of ATCC 42023 grown on either carbon source were lower when the cultur e medium contained a complex nitrogen source instead of ammonium sulph ate. The pullulan content of the polysaccharide elaborated by sucrose- grown cells on day 5 was found to be highest on soytone, peptone or co rn steep liquor. The pullulan content of the polysaccharide produced b y corn syrup-grown cells on day 5 was shown to be highest on peptone. The lowest pullulan content of the polysaccharide synthesized by the f ungus, using either carbon source, was found to occur after growth on casamino acids.