细菌纤维素发酵条件的优化及结构的初步研究

通过单因素及正交实验探索出AcetobacterxylinumNUST4·2合成细菌纤维素的发酵条件为:葡萄糖1·5%、蔗糖1·0%、蛋白胨1·5%、醋酸0·08%、Na2HPO40·27%、MgSO40·025%,接种量8%,pH5·5,28℃静置培养7d,纤维素产量为3·348g/L培养基(干重)。接着利用活性炭柱分离和气-质联用色谱(GC-MS)鉴定了发酵产物的单体成分为葡萄糖;采用固体CP/MAS13CNMR、透射电镜(TEM)、X-射线衍射表征了发酵产物的结构,得知该产物具有典型的网状结构,纤维束尺寸为纳米级且结晶度很高。

Optimization of Culture Conditions for Bacterial Cellulose Production and Preliminary Study on Its Structure

The optimum culture conditions for bacterial cellulose production were obtained by single-factor and orthogonal experiments.The conditions are as follows: 1.5% glucose, 1.5% peptone, 1.0% sucrose, 0.08% HAc, 0.27% Na_2HPO_4·12H_2O, 0.025% MgSO_4·7H_2O, 8% inoculation amount, pH 5.5. The maximum yield of cellulose was 3.348 g/L (dry weight) at 28℃ in stationary culture for 7 days. The structural units of fermentation products were delermined as glucose using active carbon column and gas chromatograph-mass spectrometer coupling(GC-MS). The fermentation products were identified as cellulose on the basis of transmission electron microscopic (TEM) observation, solid CP/MAS~~13C nuclear magnetic resonance (CP/MAS~~13C NMR) and X-ray diffraction spectra. It is seen that the products had network structure with in-twisting ribbons, nanometer ribbons and high crystallinity. All of the results indicated that fermentation products were bacterial cellulose.