Influencing Factors of Fermentation and Bioactivity of Aureobasidium pullulan LHS-m022 Melanin-Glucan
To explore the influencing factors of fermentation and bioactivity of Aureobasidium pullulan LHS-m022 melanin-polysaccharide,using strain fermentation,isolation and extraction,and biological detection methods,the properties of the fermentation broth,product yield,bioconversion rate and bioactivity were determined and analyzed. The results showed that the best carbon and nitrogen sources of LHS-m022 melanin-polysaccharide fermentation were sucrose and casein peptone,and the optimal concentration of sucrose was 60 g/L. The optimal amount of indu-cer L-dopa in the fermentation medium was 2.0 g/L,and the blackening activity and bioconversion rate of the fermentation broth were 2.481 and 71.93%,respectively. The optimal amount of cell permeating agent rhamnolipid was 0.021 μL/L,and the blackening activity and bioconversion rate of fermentation broth were as high as 2.794 and 73.9%,respectively. Full wavelength scan,FTIR and HPLC analysis showed that WAI was melanin,and PsB was melanin-glucan structure. The research revealed that the crude melanin-glucan samples treated above 121℃ still gave 95.37% FR. Testing with the respective sample concentrations of 1.50 g/L and 2.00 g/L yielded the corres-ponding 99.55% hydroxyl radical scavenging activity and 99.00% antioxidant activity.