Recovery of functionally active trypsin inhibitor (SBTI) and lipoxygenase (LOX) from soymilk via multimodal technique

Commercially available epoxy activated polymers Immobeads and Dilbeads were functionalized to 1,2-amino alcohol derivatives and screened for binding and release of soybean trypsin inhibitor (SBTI) and lipoxygenase (LOX) in soymilk. Moderately hydrophobic polymer DILBEAD-VWR functionalized with diethylamine (DIL-DEA) was found to bind SBTI and LOX (3.5 ± 0.3 mg·g− 1) without causing protein denaturation. Bound proteins were selectively released by changing the pH of eluting buffer. LOX was obtained in 70 ± 5% overall yield with a purification factor of 5 ± 0.5. The eluent containing SBTI was treated with bovine serum albumin coated polymer (Immobead 350) to obtain SBTI in 61% overall yield and a purification factor of 13.5. The recovered DIL-DEA polymer as well as BSA coated polymer were recycled at least 10 times without any appreciable change in performance.