Abstract: A non-pigmented mutant having enhanced ability to produce pullulan was successfully obtained using Aureobasidium pullulan NG as the original strain by UV-induced mutagenesis and was named as UVMU3-1. Compared with the original strain, the mutant strain UVMU3-1 displayed similar capability of growth and differentiation. The polysaccharide produced by the mutant strain was identified as pullulan by infrared spectroscopy. Tank fermentation experiments showed that the pullulan-producing capability of the mutant strain was higher than that of the original strain and that the 72 h cultivation of 200 mL of seed culture of the mutant in 5 L of YDA culture medium provided a glucose conversion of 52.78%. In conclusion, UVMU3-1 is a potential strain for pullulan production in industrial fermentation.

Key words: UV mutagenesis, Aureobasidium pullulans, pullulan