Screening and identification of a strain of Aureobasidium pullulans and its application in potato starch industrial waste

Pullulan and melanin have become important secondary metabolites that are now widely studied. In this study, a strain of Aureobasidium pullulans HIT-LCY3(T) was used to ferment potato starch industrial waste to produce pullulan and melanin. After optimization, the culture conditions for the fermentation medium were obtained: inoculum age of 48 h, initial pH of 6.0, inoculation quantity of 1.5%, temperature of 26 ?, fermentation time of 5 d and speed of 160 rpm. Under these conditions, the yield of pullulan was 23.47 g/L with a molecular weight (MW) of 1.21 x 10(6) Da and the yield of melanin was 18.98 g/L. In addition, the adaptive evolution could significantly increase the yield of pullulan and melanin and the air-floating fermenters was more conductive to product accumulation. Through the 5 L small-scale test and 1000 L pilot test, the yield of pullulan reached 16.52 g/L with molecular weight of 0.92 x 10(6) Da and the yield of melanin was 12.08 g/L at the trial production of 30,000 L. This work could provide strong support for industrial production and new guidance for waste utilization and environmental protection.

Automated summary

In this study, the strain Aureobasidium pullulans HIT-LCY3(T) was used to ferment potato starch waste to produce pullulan and melanin. The optimization of culture conditions led to high yields, and the use of adaptive evolution and air-floating fermenters further increased production. Small-scale and pilot tests confirmed the industrial potential of the process.