García-Mogollón Carlos Alberto, Mendoza Diego F, Quintero-Díaz Juan Carlos
Facultad de Ingeniería, Universidad de Sucre, Cra. 28 No. 5-267, Sincelejo, 050010, Sucre, Colombia.
Departamento de Ingeniería Química, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, 050010, Antioquia, Colombia.
Heliyon. 2024 Aug 22;10(17):e36587. doi: 10.1016/j.heliyon.2024.e36587. eCollection 2024 Sep 15.
Due to the electrical nature of the cell, it is possible to modulate its behavior through the application of non-lethal external electric fields to improve fermentation processes. In this work, a microbial cell system with a chamber and two electrodes inside and connected to a voltage source was used. One of the electrodes was kept isolated to create an electric field without the flow of current. Cultures with two ethanol-producing microbial strains ( and mobilis) were conducted in this device. The application of voltages between 0 and 18 V was evaluated to determine the impact of the generated electric field on ethanol production. To analyze the possible effect of the field on the central carbon metabolism in each strain, biochemical-based kinetic models were formulated to describe the experimental fermentation kinetics obtained. It was found that low applied voltages did not have significant effects on growth rate in either strain, but all voltages evaluated increased substrate consumption and ethanol production rate in . , while only 18 V affected these rates in . , indicating that . was the most sensitive to the electric field. At the end of the fermentation, significant increases in ethanol yields of 10.7% and 19.5% were detected for . and . , respectively. The proposed mathematical models showed that substrate transport through the membrane catalyzed by the phosphotransferase system (PTS) for . and hexose transport proteins mechanism and hexokinase (HK) activity for . and the transformation of pyruvate to ethanol, catalyzed by the decarboxylase (PDC) and alcohol dehydrogenase (ADH) enzymes, were the reactions most affected by the application of the external field.
由于细胞的电性质，通过施加非致死性外部电场来调节其行为以改善发酵过程是可行的。在这项工作中，使用了一个带有腔室且内部有两个电极并连接到电压源的微生物细胞系统。其中一个电极保持隔离状态以产生无电流流动的电场。在该装置中对含有两种产乙醇微生物菌株（运动发酵单胞菌和嗜糖假单胞菌）的培养物进行了实验。评估了0至18 V电压的施加情况，以确定所产生的电场对乙醇生产的影响。为了分析电场对各菌株中心碳代谢的可能影响，构建了基于生化的动力学模型来描述所获得的实验发酵动力学。结果发现，低施加电压对两种菌株的生长速率均无显著影响，但所评估的所有电压均提高了嗜糖假单胞菌的底物消耗和乙醇产率，而只有18 V影响了运动发酵单胞菌的这些速率，这表明运动发酵单胞菌对电场最为敏感。在发酵结束时，分别检测到嗜糖假单胞菌和运动发酵单胞菌的乙醇产量显著提高了10.7%和19.5%。所提出的数学模型表明，对于嗜糖假单胞菌，通过磷酸转移酶系统（PTS）催化的底物跨膜转运，以及对于运动发酵单胞菌，己糖转运蛋白机制和己糖激酶（HK）活性，还有由脱羧酶（PDC）和乙醇脱氢酶（ADH）催化的丙酮酸向乙醇的转化，是受外部电场施加影响最大的反应。
