Study On Enzymology Characteristics And Immobilization From Endophytic Chaetomium Globosum S108

An endophytic fungi Separated from the DongXiang wild rice which was found it could switch gglycyrrhizin?GL?to Glycyrrhetinic acid monoglucuronide,?GAMG?.The paper has studied?-D-Glucuronidase?BDGE?from the fungi,and showed its purification,characterization and immobilization.The fermentation was through ammonium sulfate,glucan G25 desalination and G100 separation,DEAE-52 ion exchange to get pure BDGE.Mass spectrometric analysis showed the monomer molecular weight was 91.1 kDa,pI was 5.95.The optimum temperature was 45°C and the reaction conditions of pH 6.0.The enzyme had a great thermal stability and pH stability.After the detection,the results showed the Km=0.312mmol/L.Maximum response speed Vmax=2.92 mmol/L·min.every characters were better than current reports.With sodium alginate as embedding material,glutaraldehyde as crosslinking agent,the crosslinking embedding method of combination of?-D-glucuronidase immobilization conditions and immobilized enzyme biocatalyse process were studied.Results display that the best immobilized conditions was obtained when sodium alginate was 1.5%,glutaraldehyde was 1.5%,crosslinking time was 30 min,adding enzyme quantity was 3500U and calcium chloride concentration was 2%.Optimum temperature immobilized enzyme is 45 ^oC-55 ^oC,and the optimum pH is5.0-7.0.4 mg/ml glycyrrhizin?GL?can stimulate enzyme activity,but glycyrrhetic acid mono-?-D-glucuronide?GAMG?had no obvious effect on enzyme activity.however,glucose had reversible inhibition on enzyme activity.Mg²⁺,Ba²⁺,Na⁺,K⁺and other metal ions had different degrees of promoting effect on enzyme activity,and Cu²⁺had irreversible inhibition on enzyme activity.Immobilized?-D-glucuronicdase enzyme activity after 15 times catalytic reaction still remained more than71%.