Strategy of oxygen transfer coefficient control on the l-erythrulose fermentation by newly isolated Gluconobacter kondonii
2016
Pan, Long | Fang, Ya-kun | Zhou, Pei | Jin, Kui-qi | Wang, Gang | Liu, Yu-peng
The effect of diverse oxygen transfer coefficient on the l-erythrulose production from meso-erythritol by a newly isolated strain, Gluconobacter kondonii CGMCC8391 was investigated. In order to elucidate the effects of volumetric mass transfer coefficient (kLa) on the fermentations, baffled and unbaffled flask cultures, and fed-batch cultures were developed in present work.With the increase of the kLa value in the fed-batch culture, l-erythrulose concentration, productivity and yield were significantly improved, while cell growth was not the best in the high kLa. Thus, a two-stage oxygen supply control strategy was proposed, aimed at achieving high concentration and high productivity of l-erythrulose. During the first 12h, kLa was controlled at 40.28h⁻¹ to obtain high value for cell growth, subsequently kLa was controlled at 86.31h⁻¹ to allow for high l-erythrulose accumulation.Under optimal conditions, the l-erythrulose concentration, productivity, yield and DCW reached 207.9±7.78g/L, 6.50g/L/h, 0.94g/g, 2.68±0.17g/L, respectively. At the end of fermentation, the l-erythrulose concentration and productivity were higher than those in the previous similar reports.
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