低相对分子质量细菌纤维素的生物合成

通过木醋杆菌菌株HN001静态培养,生物合成了低相对分子质量细菌纤维素(LMBC),其培养基是以海南椰子水为原料,添加了糖和其他盐类化合物。研究了影响LMBC产率的几个因素,如培养温度、培养时间和培养基初始pH。获得高产率LMBC的适宜条件是:培养时间72 h,培养温度33℃,培养基初始pH=4,LMBC产率达1.2 g/L。用凝胶过滤色谱仪(GFC)测定了其相对分子质量及其分布。研究了培养基初始pH从3.5到5.5变化对LMBC相对分子质量及其分布的影响,结果表明,该pH范围内相对分子质量的变化不大,其分布指数均约为1.3,说明相对分子质量均匀。用透射电镜测试了其形貌,证明LMBC的形貌近似球形,大小约20 nm;LMBC冷冻干燥后经红外光谱确证了其结构。

Biosynthesis of Low Relative Molecular Mass Bacterial Cellulose

The biosynthesis of low relative molecular mass bacterial cellulose(LMBC) by static culture of Acetobacter xylinum strain HN001 in special flasks was investigated.The medium was prepared with coconut-water by adding sugar and other salts.Under the optimal conditions that the culture time was about 72 h and culture temperature about 33 ℃,LMBC was produced with high yield of 1.2 g/L.Relative molecular mass(MM) and molecular mass distribution(MMD) of LMBC were tested by gel filtration chromatograghy(GFC).Results showed that with initial pH of the culture medium in the range 3.5 to 5.5,MM of the product does not vary notably and the MMD keeps almost fixed at 1.3.TEM image of LMBC showed that the molecule behaves as spheric coil in solution and its size was about 20 nm.Structure of freeze-dried LMBC powder was confirmed by FTIR.