PH Recycling Aqueous Two-Phase Systems Applied In Extraction Of Maitake ?-glucan And Mechanism Analysis

?-glucan is a kind of bioactive substance in the cell walls of fungi and can be used as an efficient biological response modifier(BRM)which exerts a variety of biological activities,such as enhancing immune system,the prevention and treatment of tumor,etc.Maitake ?-Glucan among Fungal polysaccharides has a stronger biological activity,i.e,significant antitumor activity,lowering blood pressure,anti-HBV activity,anti-HIV virus and improving immune system,etc.Presently,the extraction methods of Maitake ?-Glucan are ultrasonic-enzymatic;hot water extraction and cold alkali extraction;water and ethanol extraction followed by ion exchange chromatography or gel column chromatography,etc.The above methods are endowed with more steps;time consuming;costly;easily polluting the environment,etc.This topic attempts to apply pH recycling aqueous two-phase systems in separation and purification of Maitake ?-Glucan.Aqueous two-phase system(ATPS)is composed of two hydrophilic substances mixed under certain concentration which can form two phases spontaneously.It has several features:mild extraction conditions;large handling capacity;easy to enlarge;simple and continuous operation,etc.pH sensitive polymers were used to synthesize PADB/PMDM ATPS which can separate Maitake ?-Glucan.Different concentrations of polymers,various kinds of salt ions,pH and temperature for partition of ?-Glucan in ATPS were investigated.In the experiments,10 groups of polymer concentration(1.5%/1.5%;1.5%/2.5%;1.5%/3.5%;2.5%/2.5%;2.35%/2.65%,etc)were prepared.To control temperature in the range 25-45? and to adjust the pH in the range of 8.00-8.40 were a necessary.Experimental results show that in PADB/PMDM aqueous two-phase systems,Maitake ?-Glucan was mainly enriched in PADB phase.Phase forming polymers could be recycled by adjusting the pH value and the recovery was above 95%for the first time.Furthermore,with this 2.5%PADB/2.5%PMDM ATPS,7.489 partition coefficient and 96.92%extraction recovery for ?-Glucan were obtained in the presence of 30mmol/L KBr,at pH 8.20,30?.Furthermore,Fourier transform infrared spectra,ForteBio Octet system and Low-Field Nuclear Magnetic Resonance(LF-NMR)were introduced for elucidating the partition mechanism of ?-Glucan.Especially.LF-NMR was firstly used in the mechanism analysis in partition of aqueous two-phase systems.The change of transverse relaxation time(T2)in ATPS could reflect the interaction between polymers and ?-Glucan.With the above experimental results.Maitake crude polysaccharide was studied and it obtained the consistent partition effect with the pure ?-Glucan which lays the theoretical foundation for directly purification fiom Maitake fiuiting body powder.