Study On Extraction Of L-arginine In Aqueous Two-phase System

Aqueous two-phase extraction is a new solvent extraction technology, isdeveloped for the extraction of bioactive substances in recent years. Aqueoustwo-phase extraction is similar to general solvent extraction, but has moreadvantages. It can continuous operation under the room temperature and theatmospheric pressure to protect bioactive substances. Its processing is easy and highefficiency. Aqueous two-phase extraction has been widely applied in the chemicalengineering, food, medicine, cell biology and other fields.In this thesis, the distribution behavior of L-lysine and L-arginine in threecommon aqueous two-phase systems was detailedly studied, and their distributionrules were obtained. These rules provide the references for the extraction ofL-arginine from the mixture of L-lysine and L-arginine by aqueous two-phaseextraction technology. The main contents are as follows:1）The polyethylene glycol-dextran aqueous two-phase system was used to extractL-lysine and L-arginine. Effects of the molecular weight of polyethylene glycol,concentration of polyethylene glycol6000and dextran40000, pH value, temperatureand time on extraction were investigated. The results indicated that the partitioncoefficient K of L-lysine and L-arginine decreased with the increasing of themolecular weight of polyethylene glycol and concentration of polyethylene glycol6000and dextran40000, increased with the increasing of pH value, the rise oftemperature and the extension of time; The rate of extraction of L-lysine andL-arginine decreased with the increasing of the molecular weight of polyethyleneglycol and concentration of dextran40000, increased with the increasing ofconcentration of polyethylene glycol6000and pH value, the rise of temperature andthe extension of time.2） L-lysine and L-arginine extraction by the-aqueous two-phase system(polyethylene glycol-dispotassium hydrogen phosphate) were studied. The resultsindicated that the partition coefficient K of L-lysine and L-arginine decreased withthe increasing of the molecular weight of polyethylene glycol and concentration ofpolyethylene glycol4000, the rise of temperature and the extension of time, increased with the increasing of concentration of dispotassium hydrogen phosphateand pH value; The rate of extraction of L-lysine and L-arginine increased with theincreasing of the molecular weight of polyethylene glycol and concentration ofdispotassium hydrogen phosphate, the rise of temperature and the extension of time,decreased with the increasing of concentration of polyethylene glycol4000and pHvalue.3）The ethanol-dispotassium hydrogen phosphate aqueous two-phase system wasused to extract L-lysine and L-arginine. The results indicated that the partitioncoefficient K of L-Lysine decreased with the increasing of concentration of ethanol,the rise of temperature and the extension of time, increased with the increasing ofconcentration of dispotassium hydrogen phosphate and pH value, the partitioncoefficient K of L-arginine increased with the increasing of concentration of ethanoland dispotassium hydrogen phosphate, the rise of temperature and the extension oftime, increased with the increasing of pH value; The rate of extraction of L-lysineand L-arginine decreased with the increasing of concentration of ethanol and pHvalue, increased with the increasing of concentration of dispotassium hydrogenphosphate, the rise of temperature and the extension of time.