Biotechnology, Department of Chemistry, Center for Chemistry & Chemical Engineering, Lund University, Box 124, 221 00, Lund, Sweden.
Área de Biotecnología, Instituto de Investigaciones Fármaco Bioquímicas, Facultad de Ciencias Farmacéuticas Y Bioquímicas, Universidad Mayor de San Andrés, P.O. Box 3239, La Paz, Bolivia.
World J Microbiol Biotechnol. 2019 Jun 24;35(7):101. doi: 10.1007/s11274-019-2679-9.
Propionibacterium acidipropionici produces propionic acid from different sugars and glycerol; the production can be improved by high cell density fermentations using immobilized cells that help to overcome the limitations of the non-productive lag phase and product inhibition. In this study, the use of stress factors to induce P. acidipropionici to form biofilm and its use as an immobilization procedure in fermentations in bioreactors for producing propionic acid was investigated. Citric acid and sodium chloride increased exopolysaccharide production, biofilm forming capacity index and trehalose production. Analysis of the expression of trehalose synthesis-related genes otsA and treY by RT-qPCR showed significantly increased expression of only treY during log phase with citric acid, while FISH analysis showed expression of treY and luxS under the influence of both stress factors. The stress factors were then used for development of microbial biofilms as immobilization procedure on Poraver® and AnoxKaldnes® carriers in recycle batch reactors for propionic acid production from 20 g/L glycerol. Highest productivities of 0.7 and 0.78 g/L/h were obtained in Poraver® reactors, and 0.39 and 0.43 g/L/h in AnoxKaldnes® reactors with citric acid and NaCl, respectively.
丙酸短杆菌可以将不同的糖和甘油转化为丙酸；通过使用固定化细胞进行高密度发酵可以提高生产效率，这有助于克服非生产性迟滞期和产物抑制的限制。在这项研究中，研究了使用应激因子诱导丙酸短杆菌形成生物膜，并将其用作生物反应器中发酵生产丙酸的固定化程序。柠檬酸和氯化钠可以增加胞外多糖的产生、生物膜形成能力指数和海藻糖的产生。通过 RT-qPCR 分析海藻糖合成相关基因 otsA 和 treY 的表达情况表明，仅在对数生长期添加柠檬酸时，treY 的表达显著增加，而 FISH 分析表明在两种应激因子的影响下，treY 和 luxS 的表达。然后，这些应激因子被用于开发微生物生物膜，作为在 Poraver®和 AnoxKaldnes®载体上进行循环分批式反应器中从 20 g/L 甘油生产丙酸的固定化程序。在添加柠檬酸的 Poraver®反应器中，分别获得了 0.7 和 0.78 g/L/h 的最高生产率，而在添加 NaCl 的 AnoxKaldnes®反应器中，分别获得了 0.39 和 0.43 g/L/h 的最高生产率。
