This work reports on production of ethanol with simultaneous fixing of nitrogen (N2) using the anaerobic bacterium Zymomonas mobilis DSM 473. A batch fermentation with an initial glucose concentration of 50 g L-1, an initial pH of ∼5.5, an inoculum size of 10% by volume and a N2 feeding rate of 50 mL min-1 without mechanical agitation was found to provide the highest ethanol productivity (0.401 g L-1 h-1). Ethanol yield on glucose exceeded 97% of the theoretical maximum. The nitrogen content of the microbial biomass was 10.4% w/w at 65 h and all of it was derived by fixation of dinitrogen. Repeated-batch fermentations were investigated for ethanol production using simultaneous nitrogen fixation. A 2-cycle repeated-batch fermentation lasting 71 h gave a maximum ethanol yield on glucose of 0.475 g g-1 and an ethanol productivity of 0.675 g L-1 h-1. The yield (0.415 g g-1) and productivity (0.638 g L-1 h-1) were reduced in a 3-cycle repeated batch operation lasting 94 h. The need to fix nitrogen did not reduce the final achievable ethanol concentration, or the ethanol yield on glucose, relative to fermentations provided with fixed nitrogen, but did reduce the ethanol productivity by ∼82% because less cell mass was produced.

中文翻译：

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运动发酵单胞菌同时固氮和生产乙醇。

这项工作报道了使用厌氧菌运动发酵单胞菌DSM 473生产乙醇并同时固定氮（N2）的过程。分批发酵的初始葡萄糖浓度为50 g L-1，初始pH值为〜5.5，接种量为发现在不进行机械搅拌的情况下，按体积计10％和N2进料速率为50 mL min-1可提供最高的乙醇生产率（0.401 g L-1 h-1）。葡萄糖上的乙醇产率超过理论最大值的97％。微生物生物量的氮含量在65 h时为10.4％w / w，所有氮都是通过固定二氮得到的。使用同时固氮技术，研究了分批重复发酵的乙醇生产。持续71小时的2周期重复批发酵产生了最大的乙醇乙醇产量（0.475 g g-1）和0.675 g L-1 h-1的乙醇生产率。在持续94小时的3循环重复批处理操作中，产量（0.415 g g-1）和生产率（0.638 g L-1 h-1）降低了。相对于固定氮的发酵，固定氮的需求不会降低最终可达到的乙醇浓度或葡萄糖在乙醇上的产率，但是由于产生的细胞较少，因此确实使乙醇的生产率降低了约82％。