Laboratoire de Génie Chimique Biologique, Université Blaise Pascal, 63170 Aubiere, France.
Biotechnol Bioeng. 1989 Jan 20;33(4):394-405. doi: 10.1002/bit.260330404.
Rate and yield expressions relating to biomass and xanthan formation and to nitrogen, glucose, and oxygen consumption were established for Xanthomonas campestris batch fermentations in a bubble column. Microbial growth was described by the logistic rate equation, characterized by a maximum specific growth rate mu(M) = 0.5 h(-1) and a maximum attainable cell concentration provided by nitrogenous compounds. With regard to carbon metabolism, the decrease with time in experimental yields and in the experimental specific rates of xanthan production and glucose assimilation demonstrated the inadequacy of the Luedeking-Piret model. These decreases were connected to the simultaneous drop in dissolved-oxygen tension observed during xanthan synthesis. The knowledge of metabolic pathways and energetic balance were used to establish the relationships between substrate utilization, ATP generation, and xanthan production. The model was structured by assuming the oxygen limitation of both the respiration rate and the efficiency of the oxidative phosphorylation mechanism (P/O ratio). Consequently, the specific rates and yield expressions became dependent on the dissolved-oxygen tension, i.e., of the volumetric oxygen transfer in the fermentor.
建立了黄单胞菌分批发酵在鼓泡塔中的与生物量和黄原胶形成以及氮、葡萄糖和氧消耗有关的比生长速率和产率表达式。微生物生长由逻辑斯谛速率方程描述，其特征是最大比生长速率 μ（M）=0.5 h（-1）和由含氮化合物提供的最大可达到的细胞浓度。关于碳代谢，实验产率和黄原胶生产以及葡萄糖同化的实验比速率随时间的下降表明了 Luedeking-Piret 模型的不适用性。这些下降与在黄原胶合成过程中观察到的溶解氧张力的同时下降有关。利用代谢途径和能量平衡的知识，建立了基质利用、ATP 生成和黄原胶生产之间的关系。该模型通过假设呼吸速率和氧化磷酸化机制（P/O 比）的效率受到氧气限制来构建。因此，比速率和产率表达式取决于溶解氧张力，即发酵罐中的体积氧传递。
