Optimization of Flocculation Process of Yellow Serofluid by Response Surface Methodology and Its Metabolomics Analysis

In order to improve the added value and utilization rate of yellow serofluid and alleviate the environmental pollution caused by the discharge of yellow serofluid, the soluble solids in yellow serofluid were flocculated. On the basis of single factor experiment, the flocculation process of soluble solids in yellow serofluid was optimized with response surface methodology. The contents of protein and total sugar, BOD (biochemical oxygen demand), COD (chemical oxygen demand) and metabolomics of yellow serofluid before and after flocculation were determined. The experimental results showed that the optimal technological parameters of flocculation sedimentation of soluble solids in yellow serofluid were as follows: Chitosan content was 0.54 mg/mL, sodium alginate content was 0.24 mg/mL, pH was 4.4, temperature was 47 ℃, and the sedimentation rate of soluble solids in yellow serofluid was (46.26%±0.38%). Protein content decreased by 40.68% and total sugar content decreased by 8.41%. The removal rates of BOD and COD were 43% and 40.95%, respectively. Metabolomics experiment results showed that 66 compounds in yellow serofluid were significantly changed before and after flocculation. The results showed that flocculation could effectively reduce the content of soluble solids in yellow serofluid, which provides a certain reference for further development and utilization of yellow serofluid.