Study On Separation And Purification Of Laminine

Laminine is first extracted from the marine biological kelp,which has the functions of lowering blood pressure,antibacterial and lowering blood lipids,and is regarded as a candidate drug for the treatment of hypertension.The efficiency of the existing separation and purification process is low,and the purity is not up to the medicinal standard.This topic is mainly aimed at the chemical synthesis of the product of laminine,the use of ion exchange resin and crystallization of the two separation methods combined to carry out the separation and purification of laminine experiment,and the use of response surface method optimization verification.In this paper,SA-2-Ⅱ and WA-2 resins for amino acids were selected for the first time for the preliminary separation and purification of laminine.The adsorption model fitting and single factor adsorption and desorption experiments were carried out to explore the separation conditions of ion exchange resin.The fitting results showed that Langmuir isothermal adsorption and pseudo-second-order adsorption kinetic model could better simulate the adsorption process.The results of single factor experiment show that SA-2-Ⅱ resin is the best.The optimal adsorption conditions are as follows:adsorption temperature 20℃,volume of laminine solution 120 m L,adsorption p H 4.5,adsorption time 4 h,and dynamic equilibrium can be achieved.At this time,the adsorption capacity is 102 mg/g.The eluent is 0.5 mol/L ammonia,the volume is 110 m L,the elution time is 5 h,and the optimal desorption rate is 92%.Under these conditions,the recovery of laminine is 83.7%.On the basis of ion exchange resin purification,laminine was further purified by crystallization.In this paper,the ultrasound-assisted crystallization process is used for the purification of laminine for the first time,which can effectively shorten the crystallization process,improve crystal purity and yield.The crystallization conditions established by single factor experiment are as follows: crystallization temperature 15℃,initial concentration of laminine solution 20%（W/W）,adding speed of dissolving agent acetone 0.6 m L/min,ultrasonic time 12 min,ultrasonic power 150 W,adding amount of crystal seed 1%,crystallization time 8 h.Response surface methodology was used to optimize crystallization process,and the effects of key parameters（crystallization temperature,crystallization time,ultrasonic power）and interaction on crystallization were explored.The optimum crystallization conditions were determined as follows: crystallization temperature 15.4℃,crystallization time 8.97 h,ultrasonic power 148.65 W.The yield predicted by the model is 94.50% and the purity is 90.02%.The validity of the model was verified under the optimal conditions: the crystallization yield of laminine was 94.00% and the purity was90.50%,and the predicted values were in good agreement with the experimental values,which proved the accuracy of the response surface model.In conclusion,this paper establishes a highly efficient separation and purification process of laminine,which can effectively solve the problems of long time consuming and low recovery of existing separation and purification methods.It is of great significance for subsequent pilot scale amplification and industrial production of laminine.