The aim of this study was to improve the yield of citric acid (CA), an industrially valuable metabolite, obtained during Yarrowia lipolytica yeast culturing. To this end, Y. lipolytica cells were immobilized on a novel bacterial cellulose (BC) based carrier and subjected to four subsequent cycles of fed-batch culturing. During the fermentation process, yeasts metabolic stability, glucose consumption and CA production were analyzed. The results of our study have shown that BC-immobilized yeasts utilized more glucose than free cells and that the metabolic activity of BC-immobilized cells and the resultant CA production remained on a stable level throughout 4 fermentation batches, while the drop in free cells’ metabolic stability and the consequent drop in CA production was observed with each subsequent batch. Also, the overall concentration of CA product was higher in immobilized vs. free yeasts (121−129 g/L vs. 99−110 g/L, respectively). The presented results indicate that the application of a BC carrier for Y. lipolytica culturing correlates not only with a higher yield of CA product but also with more stable and repeatable conditions of the biotechnological fermentation process. The results obtained in this study may find multiple biotechnological applications in which immobilization of various types of cells is required.

这项研究的目的是提高解脂耶氏酵母酵母培养过程中获得的工业上有价值的代谢产物柠檬酸（CA）的产量。为此，解脂耶氏酵母将细胞固定在新型细菌纤维素（BC）基载体上，并进行四个连续的分批补料培养。在发酵过程中，分析了酵母的代谢稳定性，葡萄糖消耗和CA产生。我们的研究结果表明，固定有BC的酵母比游离细胞使用更多的葡萄糖，并且固定了BC的细胞的代谢活性和所得的CA产量在4个发酵批次中都保持稳定水平，而游离细胞的下降在随后的每批中都观察到了代谢的稳定性以及随之而来的CA产量的下降。同样，固定化酵母中CA产物的总浓度要高于游离酵母（分别为121-129 g / L和99-110 g / L）。给出的结果表明，BC载体在解脂耶氏酵母的培养不仅与CA产物的较高产率有关，而且与生物技术发酵过程的更稳定和可重复的条件有关。在这项研究中获得的结果可能会发现多种生物技术应用，其中需要固定各种类型的细胞。