细菌纤维素管的发酵条件优化及结构性能研究

Optimization of fermentation conditions for bacterial cellulose tube and study on its structure performance

木醋杆菌是一种革兰氏阴性专性需氧菌,采用透气管材硅胶管作为发酵容器生产细菌纤维素(Bacterial Cellulose,BC)管,实验中考察发酵培养基种类、发酵时间、接种量对BC管产量的影响。结果表明,最适发酵时间为6 d,发酵培养基为复合培养基,最适接种量为4%(v/v)。采用FTIR、XRD对BC管的结构性能进行表征,结果发现BC管的结晶度稍低于BC膜,BC管的拉伸性能达到50.25 MPa,与BC膜相当。采用原子力显微镜(AFM)观察BC管的微观形貌,发现BC管是由纤维束高度缠绕而形成,与BC膜相比,BC管的纤维束大小相差较大,这也可能是造成BC管在结晶度和拉伸性能上稍低于BC膜的原因。该研究可为BC管在高附加值的食品包装材料、组织工程支架材料等的应用提供基础数据。

Acetobacter xylinum are γ-negative, aerobic, rod-shaped bacteria. Bacterial cellulose （BC） tube was produced by fermenting Acetobacter xylinum on inner surface of oxygen-permeable silicone tube. The effects of culture medium, fermentation time, and inoculum on the yield of BC tube were studied. The culture medium was complex culture. The maximum BC tube concentration was achieved after culture with 4 % （v/v） inoculums for 6 days. The bacterial cellulose tube was characterized by FTIR and XRD. The crystallinity index of the BC tubes was 82.6 % , which was slightly lower than the value of BC membrane. Tensile strengths of BC tubes were 50.25 MPa, which was close to the value of BC membrane. The morphology of the tubes was characterized by Atomic Force Microscope （ AFM）. Results revealed that BC tube was synthesized in the form of microfibrils creating highly entangled network of micro-and nanofibers. Compared with BC membrane, microfibrils of BC tubes had significant differences in geometrical dimensions. This may be able to explain why the crystallinity and tensile properties of BC tube were slightly lower than BC membrane. The experiment results can provide basic data for the application of BC tube on high value-added food packaging materials and tissue engineering scaffolds.