Studies On Fermentation For Pectinase Production Of Apocynum Venetum L. Degumming Strains And Enzymatic Degumming

As a kind of natural health care fiber, the study of enzymatic degumming on Apocynum venetum L. has far-reaching significance in the textile field. The objective of this paper was to optimize the fermentation conditions for pectinase production of Apocynum Venetum L. degumming strains--Acinetobacter junii S-3and Bacillus subtilis S-1, enzymatic degumming, purification and some properties of pectinase from Acinetobacter junii S-3. The main results of research were as follows:1. Based on the single-factor and orthogonal experiments, liquid-state fermentation conditions for pectinase production of two strains were optimized.The optimal fermentation medium components of A. junii S-3were:banana peel powder2%, beef extract0.25%, NaCl0.2%, CaCl203%; its cultural conditions were: initial pH7.0,32℃, seed volume2%for12hours; the highest yield was up to160.7U/mL on the optimal conditions.The optimal fermentation medium components of B. subtilis S-l were:banana peel powder2%, wheat bran1%, NaCl0.2%, MgSO40.4%, CaCl20.4%; its cultural conditions were:initial pH8.0,37℃, seed volume1%for18hours; the highest yield was up to182.1U/mL on the optimal conditions.2. Initial pH value, enzyme amount (the volume of crude enzyme), bath ratio(the material-to-liquor ratio), temperature, degumming time were the main factors to enzymatic degumming for Apocynum Venetum L.. With the single-factor and response surface experiments, processing conditions of enzymatic degumming from A. junii S-3and B. subtilis S-1were optimized.The results showed that the preferred processing parameters of enzymatic degumming from A. junii S-3were as follows:Na2CO3was0.2g/100mL H2O to make initial pH9.5, enzyme amount was8.38mL, temperature was45℃, degumming time was about10h and bath ratio was1:16, then the residual gum rate was up to7.937%on the optimal conditions;The optimal proeessing parameters of enzymatic degumming from B. subtilis S-l were: enzyme amount was5.335mL, temperature was40℃, degumming time was about8h and bath ratio was1:29, then the residual gum rate was up to7.388%on the optimal conditions.3. Through ammonium sulfate precipitation, DEAE-cellulose chromatography and SDS-PAGE, the pectinase from A. junii S-3got electrophoretic purity. The relative molecular weight of the pectinase was41.5kD or so; it was stable at30～40℃, and its optimal reactive temperature was40℃; its optimal pH was9.5and the stable pH range was8.0-10.