Location and limitation of cellulose production by Acetobacter xylinum established from oxygen profiles
Location and limitation of cellulose production by Acetobacter xylinum established from oxygen profiles
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DOI：
10.1016/s1389-1723(00)89089-1
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发表时间：
2000-05-01
影响因子：
2.8
通讯作者：
Van den Heuvel, JC
中科院分区：
文献类型：
--
作者：
Verschuren, PG;Cardona, TD;Van den Heuvel, JC
在初始pH为3.0、4.0、5.0和6.0的条件下，对木醋杆菌（Acetobacter xylinum）静态发酵椰子水蔗糖进行了研究。纤维素在表面产生，并且其产生在pH为4.0和5.0时是最有利的。这些pH值也允许最佳的细菌生长。在不同的培养阶段，用微电极测量氧浓度分布，并获得陡峭的分布，穿透深度在50和100 μ m之间。底物渗透深度分析证实了发酵的第一阶段完全是氧气控制的假设。然而，扩散计算表明，在后期阶段，蔗糖也成为限制性底物，这通过纤维素生产速率随时间的下降得到证实。用微电极测量了氧在失活纤维素膜中的有效扩散系数，在所有研究条件下得到的值为1.4 × 10 ~（-9）m ~（2）/s。氧通量为5.9 x 10（-6）mol/m（2）.s，而在pH 4.0下获得的值明显更高，为9.1 x 10（-6）mol/m（2）.s。
The static fermentation of coconut water sucrose by Acetobacter xylinum was tarried out at initial pH's of 3.0, 4.0, 5.0 or 6.0. Cellulose was produced at the surface, and its production was most favourable at pH's 4.0 and 5.0. These pH values also allowed for optimal bacterial growth. Oxygen concentration profiles were measured with microelectrodes at different cultivation stages, and steep profiles were obtained with penetration depths between 50 and 100 mu m. A substrate penetration depth analysis confirmed the hypothesis that the first stage of the fermentation is entirely oxygen controlled. Diffusion calculations showed, however, that at a later stage sucrose becomes a limiting substrate also, which was confirmed by the decrease in cellulose production rate over time. The effective diffusion coefficient of oxygen in deactivated cellulose pellicles was measured with microelectrodes, and a value of 1.4 x 10(-9) m(2)/s was obtained under all investigated conditions. The oxygen flux was 5.9 x 10(-6) mol/m(2).s, while a significantly higher value of 9.1 x 10(-6) mol/m(2).s was obtained at pH 4.0.