利用玉米淀粉黄浆水发酵生产细菌纤维素的培养基优化

Optimization of culture media for bacterial cellulose production by fermentation of corn starch wastewater

玉米淀粉黄浆水是生产淀粉过程中排放的高浓度有机废水,以其作为Acetobacter xylinum DS398的基础培养基发酵细菌纤维素。采用Plackett-Burman设计和Box-Behnken响应面分析法对培养基成分进行优化,并对产物进行表征。以纤维素干重为响应值,从7个相关影响因素筛选出3个显著因子:蔗糖、磷酸二氢钾和乙醇。在此基础上,根据Box-Behnken响应面分析法确定以上三因素的最佳浓度。最优的玉米淀粉黄浆水培养基组分为:玉米黄浆水稀释比1∶4,蔗糖3.32 g/100 m L,CaCl_20.3 g/100 m L,KH_2PO_40.12 g/100 m L,Mg SO_40.05 g/100 m L,柠檬酸0.2 g/100 m L,乙醇1.50 m L/100 m L,细菌纤维素产量达到1.11 g/100 m L,为优化前的1.63倍。结果表明经优化后黄浆水培养基能够满足Acetobacter xylinum生长代谢的需要,细菌纤维素产量得到显著提高;同时傅立叶红外光谱图和场发射扫描电镜图显示产物是纯度较高的纤维素,微观结构与椰果相似。

Corn starch wastewater is a kind of high concentration organic wastewater discharged from starch processing.The study focused on producing bacterial cellulose utilized those wastewater, and optimizing medium component via adopting the Plackett- Burman design method and the Box -Behnken response surface analysis. Further,the structure of bacterial cellulose （BC）obtained from fermentation of corn starch wastewater was described by Fourier transform infrared spectrometer（FTIR） and scanning electron microscopy（SEM）.Cellulose dry weight was defined as response value, three significant factors, which were sucrose, monopotassium phosphate and ethanol, were selected through the Plackett- Burman experiment, then the respective optimum concentration of those factors was determined by response surface method （RSM）. The improved medium composition was as follows： dilution ratio of corn starch wastewater was 1：4, extra sucrose, CaCI2, KH2PO4, MgSO4,citric acid and ethanol were 3.32 g/100 mL,0.3 g/J00 mL,0.12 g/100 mL,0.05 g/100 mL,0.2 g/100 mL, 1.50 mL/L,respectively. Eventually, the yield of BC was 1.63 times than that before optimization, and reached 1.11 g/J00 mL. The results suggested that the postoptimality medium of wastewater could meet the growth and metabolism of Acetobacter xylinum DS398, hence the bacterial cellulose production were improved significantly.The micrographs of FTIR and SEM further illustrated that BC produced in medium of corn starch wastewater possesses high purity,and the product＇s microstructure may be similar to coconut.