Study On Extraction Of Bromelain From Pineapple Bean By Liquid Extraction Of Gemini Cationic Surfactant

Reverse micelle extraction technology can purify and concentrate target protein from a real system simultaneously. It is low cost and can maintain the biological activity of protein, and so far has shown advantages over conventional extraction methods and promised potential. Therefore, the technology is more and more concerned in the extraction and separation of proteins.The surfactants used in reverse micelle extraction are mostly conventional surfactant. This thesis used two novel surfactants-gemini surfactant octamethylene-1,8-bis（dimethyl dodecyl ammonium bromide） (C₁₂C₈C₁₂) and dodecane-1,12-bis（dimethyl dodecyl ammonium bromide） (C₁₂C₁₂C₁₂) reverse micelles to extract bromelain from pineapple peel. It was found that the gemini surfactants showed higher extraction efficiency than conventional surfactant. Moreover, the parameters such as the structure and content of surfactant, pH, ionic strength and dilution multiple of crude enzyme extract all affected the overall extraction efficiency, activity recovery and purification fold of bromelain. Under the optimal conditions, the recovered bromelain from pineapple peel with C₁₂C₈C₁₂ reverse micelles showed activity recovery of 163% and purification fold of 3.3, and that with C₁₂C₁₂C₁₂ reverse micelles showed activity recovery of 140%-160% and purification fold of 1.8-3.2.Therefore, C₁₂C₈C₁₂ and C₁₂C₁₂C₁₂ both can be used to extract bromelain from pineapple peel efficiently. However, C₁₂C₁₂C₁₂ reverse micelles can extract bromelain under much wider conditions than C₁₂C₈C₁₂ reverse micelles, suggesting a better application potential for the gemini surfactant with a longer spacer in protein extraction.