Study On Mechanism And Technology Of Surface-active Biomaterials-assisted Foam Fractionation For Separating Non-surface-active Biomaterials

In recent years,the application of foam fractionation in the field of biotechnology has received an increasing attention based on its significant advantage for the effective separation of a material from its diluted aqueous solution.Nevertheless,foam fractionation is performed by using bubbles as the separation media,thus the limited separation systems have been the most obvious defect of this technique.For overcoming this defect,this work proposed to study the mechanism of foam fractionation for the separation of various non-surface-active biomaterials by the assistance of different surface-active biomaterials,and develop a series of technologies for separating non-surface-active biomaterials by using foam fractionation.Firstly,using soybean isoflavones in the soy whey wastewater as the desired material,the mechanism of surface-active biomaterials-assisted foam fractionation for the separation of non-surface-active biomaterials from the system with strong foam stability has been investigated based on the interation between surface-active biomaterials and non-surface-active biomaterials.The complexation mechanism between whey soy proteins and soybean isoflavones was determined by using reverse microemulsion as the medium.A two-stage foam fractionation technology was developed for separating soybean isoflavones,and under the suitable conditions,the enrichment ratio and the recovery percentage of soybean isoflavones were 4.05 and 87.72%,respectively.Secondly,using lycopene in the tomato-based processing wastewater as the desired material,the mechanism of surface-active biomaterials-assisted foam fractionation for the separation of non-surface-active biomaterials from the system with weak foam stability has been investigated based on the interaction between surface-active biomaterials and non-surface-active biomaterials.Based on the synergistic effect of surface-active materials combination,the continuous foam fractionation technology for the separation of lycopene in the co-adsorption state has been determined by using rhamnolipid as the foam stabilizer.Under the suitable conditions,the enrichment ratio and the recovery percentage of lycopene were 3.81 and 78.16%,respectively.Thirdly,using puerarin in the Radix puerariae as the the desired material,the mechanism of surface-active biomaterials-assisted foam fractionation for the separation of non-surface-active biomaterials has been investigated,under the condition of that there are not any interactions between surface-active biomaterials and non-surface-active biomaterials.By using the modified ?-cyclodextrin-Cu ion complex as the medium,the technology of yam mucilage-assisted foam fractionation for the separation of puerarin was determined.The extraction percentage of puerarin increased by 80.12% through forming the inclusion with the modified ?-cyclodextrin-Cu ion complex.Under the suitable conditions,the enrichment ratio and the recovery percentage of puerarin were 4.32 and 82.34%,respectively.Subsequently,an integration technology of foam fractionation,acid hydrolysis and solid-liquid adsorption was developed and used for the isolation of isoflavone aglycones from the foamate.The results indicated that foam fractionation could be used to effectively remove whey soy proteins from the foamate through adjusting temperature and pH.Acid hydrolysis was performed for transforming isoflavone glycosides in the residual solution into isoflavone aglycones,and the percentage hydrolysis percentage of isoflavone glycosides reached 96.00%.By using the chitosan microspheres as the adsorbents,the recovery percentage of isoflavone aglycones was 89.65%.Finally,according to the laws of mass conservation and adsorption mass transfer,the adsorption kinetics of foam fractionation for the separation of non-surface-active biomaterials has been studied,thereby established dynamic adsorption model and determined breakthrough curve equation of non-surface-active biomaterials in the foam phase.Within the scope of experiment,the model could be well fitted to the experimental data.The effective height of mass transfer zone was evaluated to obtain the suitable feed position of continuous operation.These results provided the basis for the selective separation of a desired material from the mixture solution of non-surface-active biomaterials by using foam fractionation.In conclusion,foam fractionation could be used to effectively separate non-surface-active biomaterials based on the assistance of surface-active biomaterials.This objective of this work was to supply some new ideas for the separation and purification of non-surface-active biomaterials by using foam fractionation,and expect to facilitate the industrialization of foam fractionation.