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Nesci S, Algieri C, Trombetti F, Fabbri M, Lenaz G. Two separate pathways underlie NADH and succinate oxidation in swine heart mitochondria: Kinetic evidence on the mobile electron carriers. Biochim Biophys Acta Bioenerg 2023; 1864:148977. [PMID: 37059413 DOI: 10.1016/j.bbabio.2023.148977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 03/25/2023] [Accepted: 04/06/2023] [Indexed: 04/16/2023]
Abstract
We have investigated NADH and succinate aerobic oxidation in frozen and thawed swine heart mitochondria. Simultaneous oxidation of NADH and succinate showed complete additivity under a variety of experimental conditions, suggesting that the electron fluxes originating from NADH and succinate are completely independent and do not mix at the level of the so-called mobile diffusible components. We ascribe the results to mixing of the fluxes at the level of cytochrome c in bovine mitochondria: the Complex IV flux control coefficient in NADH oxidation was high in swine mitochondria but very low in bovine mitochondria, suggesting a stronger interaction of cytochrome c with the supercomplex in the former. This was not the case in succinate oxidation, in which Complex IV exerted little control also in swine mitochondria. We interpret the data in swine mitochondria as restriction of the NADH flux by channelling within the I-III2-IV supercomplex, whereas the flux from succinate shows pool mixing for both Coenzyme Q and probably cytochrome c. The difference between the two types of mitochondria may be ascribed to different lipid composition affecting the cytochrome c binding properties, as suggested by breaks in Arrhenius plots of Complex IV activity occurring at higher temperatures in bovine mitochondria.
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Affiliation(s)
- Salvatore Nesci
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra 50, 40064 Ozzano Emilia, BO, Italy.
| | - Cristina Algieri
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra 50, 40064 Ozzano Emilia, BO, Italy
| | - Fabiana Trombetti
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra 50, 40064 Ozzano Emilia, BO, Italy
| | - Micaela Fabbri
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra 50, 40064 Ozzano Emilia, BO, Italy
| | - Giorgio Lenaz
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Massarenti 9, Pad 11, 40138 Bologna, BO, Italy
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Mesquita TJB, Sargo CR, Fuzer JR, Paredes SAH, Giordano RDC, Horta ACL, Zangirolami TC. Metabolic fluxes-oriented control of bioreactors: a novel approach to tune micro-aeration and substrate feeding in fermentations. Microb Cell Fact 2019; 18:150. [PMID: 31484570 PMCID: PMC6724378 DOI: 10.1186/s12934-019-1198-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 08/25/2019] [Indexed: 01/24/2023] Open
Abstract
Background Fine-tuning the aeration for cultivations when oxygen-limited conditions are demanded (such as the production of vaccines, isobutanol, 2–3 butanediol, acetone, and bioethanol) is still a challenge in the area of bioreactor automation and advanced control. In this work, an innovative control strategy based on metabolic fluxes was implemented and evaluated in a case study: micro-aerated ethanol fermentation. Results The experiments were carried out in fed-batch mode, using commercial Saccharomyces cerevisiae, defined medium, and glucose as carbon source. Simulations of a genome-scale metabolic model for Saccharomyces cerevisiae were used to identify the range of oxygen and substrate fluxes that would maximize ethanol fluxes. Oxygen supply and feed flow rate were manipulated to control oxygen and substrate fluxes, as well as the respiratory quotient (RQ). The performance of the controlled cultivation was compared to two other fermentation strategies: a conventional “Brazilian fuel-ethanol plant” fermentation and a strictly anaerobic fermentation (with ultra-pure nitrogen used as the inlet gas). The cultivation carried out under the proposed control strategy showed the best average volumetric ethanol productivity (7.0 g L−1 h−1), with a final ethanol concentration of 87 g L−1 and yield of 0.46 gethanol gsubstrate−1. The other fermentation strategies showed lower yields (close to 0.40 gethanol gsubstrate−1) and ethanol productivity around 4.0 g L−1 h−1. Conclusion The control system based on fluxes was successfully implemented. The proposed approach could also be adapted to control several bioprocesses that require restrict aeration.
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Affiliation(s)
- Thiago José Barbosa Mesquita
- Graduate Program of Chemical Engineering, Federal University of São Carlos (PPGEQ-UFSCar), Rodovia Washington Luís, Km 235, São Carlos, SP, 13565-905, Brazil
| | - Cíntia Regina Sargo
- Graduate Program of Chemical Engineering-Institute of Chemistry, Federal University of Goiás (PPGEQ/IQ-UFG), Avenida Esperança, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - José Roberto Fuzer
- Graduate Program of Chemical Engineering, Federal University of São Carlos (PPGEQ-UFSCar), Rodovia Washington Luís, Km 235, São Carlos, SP, 13565-905, Brazil
| | - Sheyla Alexandra Hidalgo Paredes
- Graduate Program of Chemical Engineering, Federal University of São Carlos (PPGEQ-UFSCar), Rodovia Washington Luís, Km 235, São Carlos, SP, 13565-905, Brazil
| | - Roberto de Campos Giordano
- Graduate Program of Chemical Engineering, Federal University of São Carlos (PPGEQ-UFSCar), Rodovia Washington Luís, Km 235, São Carlos, SP, 13565-905, Brazil
| | - Antonio Carlos Luperni Horta
- Graduate Program of Chemical Engineering, Federal University of São Carlos (PPGEQ-UFSCar), Rodovia Washington Luís, Km 235, São Carlos, SP, 13565-905, Brazil
| | - Teresa Cristina Zangirolami
- Graduate Program of Chemical Engineering, Federal University of São Carlos (PPGEQ-UFSCar), Rodovia Washington Luís, Km 235, São Carlos, SP, 13565-905, Brazil.
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