Recovery Of S-adenosy Lmethionine By Supported Liquid Membranes With Strip Dispersion

S-Adenosyl-methionine （SAM） participates in biochemical reactions and has goodcurative effect in arthritis, depression, liver function disorder, etc. It is also health caremedicine to prevent cancer, cardiovascular disease and easy-aging. SAM has a goodprospect of clinical application, and the SAM demands at home and abroad continuouslyimprove.At present, SAM is mainly producted through biological fermentation. However,separating SAM from biological fermentation needs to be resolved. SAM and the residualmaterial L-methionine （Met） have similar physical and chemical properties and SAMproduct concentration in biological fermentation is very low. So it is hard to separate SAMin traditional method. Meanwhile, because of the existence of high energy sulfhydryl, it isvulnerable to resist nucleophilic attack, which lead to degrade reaction and chiralheterogeneous reaction. SAM is easily inactivated and looses its stability in thepurification process. The experiment adopted SLM-SD technology to extract andconcentrate SAM, carried out the following works.1. Research of the1mmol/L SAM enrichment by using SLM, the experimentalconditions: feed phase pH, composition of organic phase solvent, concentration ofextraction agents, organic phase volume, acid composition of stripping phase, strippingphase pH, NaCl concentration of stripping phase were optimized, it is concluded that thebest conditions for feed phase:500ml, pH=3.0,1mM SAM phosphate solution; Organicphase:400ml,2.24wt%AOT, octyl alcohol solution; Stripping phase:200ml, pH=2.2,1mol/L NaCl, sodium phosphate/sulfuric acid solution. Highest SAM recovery efficiency99.8%and extraction efficiency over99%was received in1h.2. Research of the10mmol/L SAM enrichment by using SLM, the experimentalconditions: extraction agents concentration, stripping phase pH, stripping phase buffersystem, NaCl concentration of stripping phase were analysed. Optimum prescription wasobtained:500ml, pH=3.0,10mmol/L SAM phosphate solution; Organic phase:400ml,2.80wt%AOT, octyl alcohol solution; Stripping phase:200ml, pH=3.0,0.5mol/L NaCl,sodium phosphate/sulfuric acid solution. Highest SAM recovery efficiency91.8%and extraction efficiency over99%was received in3h.3. Research of SAM separation of the10mmol/L SAM and2mmol/L Metfermentation simulation by using two step SLM-SD, the experimental parameters: firststripping phase pH, second stripping phase pH, the concentrations of extraction agentsAOT, DEHPA, TOPO, NaCl concentration of stripping phase; Process parameters such asPressure difference Δp, Strip dispersion mixing speed, volumetric flow rates of the feedphase, stripping solution were optimized. Optimum prescription was obtained: Theoptimal mixed extractants concentration in the organic solution （n-octanol as the solvent）was found to be AOT2.78wt%, DEHPA27.0wt%and TOPO1.61wt%. Meanwhile, forthe best extraction and recovery performance, pH in feed phase, in first and second stripsolution should be3.0,2.5and1.0, respectively. Under the optimal operation conditions,SAM extraction rate from the feed phase was98.7%and SAM recovery rate91.8%.Separation factor for SAM vs Met in the first step liquid membrane was2.01. Metremoval rate was85.4%.4. Transport kinetics analysis was conducted to two step SLM-SD. Under theoptimum conditions, the membrane resistance, the aqueous feed phase resistance, theorganic phase shell-side resistance, the extraction reaction resistance, the overall transferresistance were1/K_m=0.685×10⁶s/m,1/K_a=1.266×10⁶s/m,1/K₀=3.037×10⁶s/m,1/K_e=7.670×10⁶s/m and1/K=12.658×10⁶s/m. The resistance from the extraction reactionand the membrane phase in the shell-side accounts for the dominate status.