Study On The Production Of Carboxymethyl Agarose

Agarose is a neutral or nearly neutral polysaccharide extracted from red algae.Now,agarose is widely used in gel electrophoresis,immunoassay and chromatography research.After chemical modification,agarose has a lower melting temperature and solidification temperature,with important applications in biological and medical fields.In the present thesis,the production of agarose from Gracilaria agar was extracted with EDTA-Na₂,which was further investigated to prepare carboxymethyl agarose using both water and organic solvent as the reaction matrix.The main results are shown as follows:?1?by monitoring the gel strength and sulphate content,the pH value was shown could affect the quality of the agarose produced by the method of EDTA-Na₂.After extraction in 6.5 g/mL EDTA-Na₂ at pH 9.0 and 60? for 4 h,which was the optimized process,the agarose gel strength and sulfate content were detected at1987.2 g.cm^-2 and 0.61%with ash of 0.23%.?2?by using single-factor experiments and orthogonal experiment,the concentrations of NaOH and chloroacetic acid and reaction temperature and reaction time was optimized,which resulted in the extracted process for the production of in the water matrix,as the NaOH concentration of 0.64 g/g,the amount of chloroacetic acid 0.5 g/g,the reaction time of 80 min and the reaction temperature of 65?.by using the process,a scaled-up production showed the carboxymethyl agarose having a melting point of 81?,gel melting temperature of 65?,gel strength of 323.6 g.cm^-2 and gel transparency of 94.5%??3?the concentration of NaOH,amount of chloroacetic acid,reaction time and temperature were optimized to prepare carboxymethyl-agarose in organic solvent matrix using single-factor experiments and orthogonal design.As the result,the improved process consisting of the NaOH concentration of 0.2 g/g,the amount of chloroacetic acid.0.189 g/g,the reaction temperature of 60? and the reaction time of 40 min.the optimized process was shown to produce a carboxymethyl agarose with a melting point of 75?,gel melting temperature of 60?,gel strength of 275.5 g.cm^-2 and transparency of 95.4%.By doing the comprehensive study,the agarose production process was improved,the effects of process parameter were revealed,and most importantly the production of carboxymethyl agarose was investigated.These results set up a technical base for the in-depth processing of agar.