Extraction of superoxide dismutase from maize before ethanol fermentation processing

In order to improve the value of the multiple use, the processes of extracting superoxide dismutase(SOD) from maize without affecting ethanol fermentation were studied. The results showed the optimum conditions for steeping maize were as follows: 0.05 mol/L phosphate buffer(pH 7.8) added with 2∶1 solvent-to-solid ratio(v/m), temperature 40℃, time 36 h. The best technological parameters of SOD extraction were adding 2∶1 solvent-to-solid ratio 0.05 mol/L phosphate buffer(pH 7.8), extracting for 1 h. Then 40% and 90% of saturated ammonium sulfate were added to remove impurities and cause SOD to precipitate, respectively. Eventually, the crude SOD was obtained, whose specific activity reached 168.3 U/mg.