| Reverse micellar extraction is a fast mass transfer liquid-liquid bioseparation technology which can be used for large-scale process. The interaction of surfactant, organic phase and water phase in the mesoscopic scale were studied by the dissipative particle dynamics (DPD) molecular simulation methods. This paper also discussed the aggregation of surfactant and protein in the organic phase. The self-assembly behavior of reverse micelles were simulated, and the mesoscopic structures of reverse micelles were observed intuitively, these structures were consistent with the actual structures of reverse micelles. The processing of protein structure was similar to polymer, built the 'monomer' for protein. In this way, transformed the molecular structure of protein to mesoscopic structure which could be applied in DPD simulations. The subject chose lysozyme and papain as the target substance for the CTAB/isooctane/n-hexanol system. The simulation results indicate that the target proteins have good interaction with CTAB reverse micelles and the proteins can stably exist in polar cores. These forecast that the proteins can be extracted by CTAB/isooctane/n-hexanol system.According to the simulation results, this paper studied the extraction yield in reverse micellar extraction of papain. The effects of aqueous phase pH, ionic strength, chaotropes, etc were discussed. The experiment results show that under the conditions of [CTAB]=0.02 mol/L, n-hexanol/isooctane (V/V)=1:5, phase volume ratio=1:1, low papain concentration, pH=10.5 and 15% ethanol(V/V) in forward extraction, pH=5.2, [GuHCl]=0.2 mol/L and 20% ethanol(V/V) in backward extraction, the highest extraction recovery of forward extraction and back extraction are 76.9% and 98.7%, respectively. The recovery of papain can reach to 75.9% by reverse micellar extraction of CTAB/isooctane/n-hexanol system.This indicates that the papain can be extracted by the reverse micelles. The research verified the results of the simulation. |
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