| Radial flow chromatography (RFC) is a new technique of chromatography purification. RFC has several prominent advantages like higher flow rate, larger throughput, lower column pressure and easier linear amplication compared with axial flow. With the growing concern on polysaccharide, scale production of the polysaccharide resolving by new chromatographic separation technology is pending further study. In this study, a commercial method for polysaccharide from fruiting bodies of Ganoderma lucidum was studied, mainly using radial flow chromatography and some other supplementary means. The main purpose of this paper was to provide basic data and guidance for the production of Ganoderma lucidum polysaccharide. The main work and results were as follows:1. Kinetic of radial flow chromatography:A mathematical model for the radial flow chromatography (RFC) was established based on the theory of longitudinal diffusion, and the effects of volume flow rate (F), height of the column (h), capacity factor and diffusion coefficient on the elution profile and column efficiency were discussed by the MATLAB simulation software; The results show that the column efficiency can be stable and efficient when the F/h ratio reaches10mL/min/cm, and when the F/h ratio is constant, the column efficiency can keep invariant. Thus, the volume flow rate can be linearly enlarged with the increase of the height of RFC.The maximum error between the model calculation and experiment is below8.8%. According to the guide of the model and based on the experimental equipment used, the volume flow rate used during the deproteinization experiment is50mL/min.2. Extracting polysaccharide of Ganoderma lucidum using complex enzymatic hydrolysis as a pretreatment:papain and cellulose was used to extract polysaccharide, and the effects of pH value, extraction temperature, extraction time, liquid-material proportion, mass fration of compound enzyme and mass fration of the papain and cellulose on the yield of polysaccharide were studied, and the optimum condition of extraction by response surface mathodolgy was as follows:pH value was7, extraction temperature was56℃, extraction time was1.5h, liquid-material proportion was1:20, mass fration of compound enzyme was3%, mass fration of the papain and cellulose was2:1, the extracion yield was3.15%, which was far more than those of hot water extraction (2.07%), microwave extraction(2.54%) and sonic extraction(2.61%).3. Tangential flow filtration coupling radial flow chromatography for separating and purificating polysaccharide:the hydrolysate was purificating and concentrating by tangential flow filtration system, the kind of polysul-fone membrane with moleculer cut off100KD was studied and chosen, and the effects of filitrting time, flowing rate of hydrolysate and concerntation multiplies on the filtraiton performance were studied. The optimum conditions were as follows:room temperature, under30psi pressure, the flowing rate of hydrolysate was500mL/min, the concerntation multiplies was15-17, the rejection ratio of polysaccharide was66.32%and deproteinization rate was82.21%.4. Contrasting with different operational paths, a commercial method for polysaccharide of Ganoderma lucidum was established:first, extracting polysaccharide of Ganoderma lucidum using complex enzymatic hydrolysis as a pretreatment, then concentrating, separating and purifing hydrolysate by tangential flow filtration coupling radial flow chromatography, and dying the purified polysaccharide liquid using sponging drying method or freeze dehydration method at last. This commercial method’s deproteinization rate was99.24%, which was18.89%and17.03%respectively, higher than those of only using radial flow chromatography and only using tangential flow filtration. And this commercial method was not only simplified the production of polysaccharide and also environmental protection and efficiency. |
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