Abstract: Protopectinase catalyzes the soluble pectin substance from protopectin and has been extensively utilized in pectin production, single cell food exploration and enzymatic cotton scouring. The factors relate to protopectinase activity and biomasses in flask culture were investigated by one factor experiments. Based on former experiments, the orthogonality test was undertaken to determine the significant factors and optimal levels within pH, inoculation content, rotate speed, the concentration of magnesium and the phosphate buffer factors with four levels respectively .the result showed that culture original pH value, the concentration of phosphate buffer are significant factors and culture original pH value 7.5, inoculation content 10%, MgSO•4 7H2O 0.04%, the concentration of phosphate buffer 0.20mol/L and rotate speed 120r/min can gain the highest protopectinase activity about 16.71U/ml.

Key words: Bacillus subtilis XZ2, Protopectinase, fermentative optimization ..