Extraction of sludge protein enhanced by electron beam irradiation and calcium oxide

In order to enhance the extraction yield of sludge protein, electron beam irradiation (EBI) pretreatment in the presence of calcium oxide was investigated. The influences of the moisture content of sludge, dose and calcium oxide additive amount on the extraction yield have been studied. The experimental conditions were optimized by response surface methodology. The optimized conditions for the extraction process of sludge protein are as follows: dose of 30.83 kGy, moisture content of 90.56%, and calcium oxide additive amount of 0.31 mg/mL. Under the optimal conditions, the protein extraction yield can reach 88.67%. Regression analysis with R2 value of 0.9964 showed a satisfactory correlation between the predicted values and experimental data. Based on the mechanism and feasibility analysis, the EBI/calcium oxide method was effective and feasible to improve the extraction yield of sludge protein.