| γ-Poly-glutamic acid (y-PGA) is a kind of biopolymers produced by some bacteria which is composed of D-and/or L-glutamic acid linked by amide linkages between a-amino and y-carboxylic acid groups. Owing to its good water-soluble capacity, γ-PGA, as an ideal biomaterilal, has a broad application in many areas such as medicinal, food and cosmetics fields.An optimum liquid fermentation technology of y-PGA produced by Bacillus subtilis natto was obtained through the single factor experiment and the orthogonal experiment. The results are as follows:the yield of y-PGA amounts to11.97g/L under the conditions of glucose2.5%,1.5%peptone,2%monosodium glutamate as culture medium at pH7.5for48hours, the shaking rate is150rpm and the sample volume50mL in250mL shaking flask. The production technology of y-PGA produced by solid-fermentation mode was also investigated, and compared with liquid-fermentation mode. y-PGA was purified by ethanol precipitation, dialysis and isoelectric point precipitation. The hydrolysate of the product was investigated with HPLC, and then the molecular weight was determined by SDS-PAGE. The results indicated that the product was a y-PGA mixture with different molecular weight other than single compound.A high molecular resin material with3D reticular structure was synthesized with y-PGA and polyethylene glycol diglycidyl ether as reactants. The structural characteristics of the resin was investigated with IR, NMR and ATM methods.The results showed that y-PGA was crosslinked completely in the presence of polyethylene glycol diglycidyl ether. The synthesized resin has a good absorbing water capability. |
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