Exploration and comparison of inborn capacity of aerobic and anaerobic metabolisms ofSaccharomyces cerevisiaefor microbial electrical current production

Abstract

Saccharomyces cerevisiae possesses numerous advantageous biological features, such as being robust, easily handled, mostly non-pathogenic and having high catabolic rates, etc., which can be considered as merits for being used as a promising biocatalyst in microbial fuel cells (MFCs) for electricity generation. Previous studies have developed efficient MFC configurations to convert metabolic electron shuttles, such as cytoplasmic NADH, into usable electric current. However, no studies have elucidated the maximum potential of S. cerevisiae for current output and the underlying metabolic pathways, resulting from the interaction of thousands of reactions inside the cell during MFC operation. To address these two key issues, this study used in silico metabolic engineering techniques, flux balance analysis (FBA), and flux variability analysis with target flux minimization (FATMIN), to model the metabolic perturbation of S. cerevisiae under the MFC-energy extraction. The FBA results showed that, in the cytoplasmic NADH-dependent mediated electron transfer (MET) mode, S. cerevisiae had a potential to produce currents at up to 5.781 A/gDW for the anaerobic and 6.193 A/gDW for the aerobic environments. The FATMIN results showed that the aerobic and anaerobic metabolisms are resilient, relying on six and five contributing reactions respectively for high current production. Two reactions, catalyzed by glutamate dehydrogenase (NAD) (EC 1.4.1.3) and methylene tetrahydrofolate dehydrogenase (NAD) (EC 1.5.1.5), were shared in both current-production modes and contributed to over 80% of the identified maximum current outputs. It is also shown that the NADH regeneration was much less energy costly than biomass production rate. Taken together, our finding suggests that S. cerevisiae should receive more research effort for MFC electricity production.

Anaerobic and Aerobic Respiration in Yeast: Small-Scale Variations on a Classic Laboratory Activity

“…In terms of the experimental setup, the results that were obtained in all sections match those expected by the literature and in larger-scale investigations. 7,11,12 The scale level of the investigation as well as the cost effectiveness, due to the common laboratory materials used, lend themselves as efficient means by which themes of kinetics can be introduced from advanced high school chemistry classes to college curricula.…”

Biological and technical challenges for implementation of yeast‐based biosensors

“…Amperometric biosensors are not without their own challenges. Different substrates oxidation processes, aerobic or anaerobic conditions and cellular growth phases have different impact on the electron transfer rate and consequently current output (Hubenova & Mitov, 2015 ; Mao & Verwoerd, 2013 ). Another important aspect affecting the electric signal is the cell adhesion to the working electrode which in turn is influenced by the electrode material.…”

Theoretical exploration of optimal metabolic flux distributions for extracellular electron transfer by

“…A fractional benefit analysis, as described previously [51,52], was conducted to quantify how each of the multiple objective terms will contribute (positively or negatively) to the overall benefit. In the analysis, a value of the quantity, designated as the fractional benefit B, is computed by adding up the fractions of the maximal values of the objectives that they can ever achieve in a particular metabolic state.…”