Bioelectrochemical systems (BES) are finding increasing applications that address modern-day needs for sustainable energy production, chemical synthesis, biosensors, water desalination, environmental bioremediation and resource extraction from waste streams. At the heart of BES are electrogenic bacteria and their electroactive biofilms (EABs). These lifeforms derive energy via oxidation of organic compounds, such as organic contaminants in wastewater, utilizing both aerobic and anaerobic pathways for respiration via the Krebs metabolic cycle. The electrons generated during the metabolic process are then transferred through an extracellular electron transfer (EET) network until reaching terminal electron acceptors. For anode-adhered EABs, the electrode serves as an electron sink. The electrode also facilitates electrical measurements, which are directly related to the EAB metabolic activity, including oxidation and subsequent EET. Characterizing metabolic activity in this way is known as electrorespirometry and provides the basis for measuring kinetic parameters associated with the EAB metabolism, which is a crucial need for ongoing BES development and optimization. Furthermore, electrorespirometry of electrode-adhered EABs can open the door to a mechanistic understanding of metabolic processes through the combination with classical equations such as Michaelis-Menten, Monod, and Nernst. One of the most well-studied EABs consists of electrogenic bacteria from G. sulfurreducens. Apart from being directly relevant to certain BES applications, monoculture G. sulfurreducens EABs nourished by an acetate nutrient solution are also considered as a model system due to straightforward single-species metabolic oxidation and simplified EET due to direct electrical connections between the anode and bioconductive groups in the EAB (notably cytochrome c enzymes). This EET contrasts with the more complex mechanisms used by other EABs, via soluble mediating redox electron shuttles. In numerous works, a four-step mechanism for G. sulfurreducens EABs has been proposed that describes the electron transport from the substrate to an electrode. This mechanism includes (i) acetate uptake and electron liberation after metabolic oxidation, followed by a series of electron transport steps, starting with (ii) electron transport to mediators at the cell exterior, followed by (iii) extracellular charge transport to the EAB/electrode interface, and (iv) final electron transfer to the electrode. Each step is guided by different factors, including rate constants, concentrations of the involved species (reactants and charge transport carriers), as well as other model-specific constants. While most studies focus on reaction bottlenecks (rate limitations) in the electron transfer mechanisms (steps ii-iv), some studies have focused on the metabolic oxidation of acetate and mass transport to and through the EAB that are related to step (i). In this work, we propose a simplified mechanism is shown in Figure , in which step (i) is conducted via the enzymedriven Krebs cycle, and steps (ii) through (iv) are considered a single electron transfer process. Despite the great advances that have been made in kinetic studies of EAB metabolism, gaps still exist in the literature. One such gap addressed in this work is related to the effect of EAB age and growth conditions on the kinetics of metabolic acetate oxidation. Most studies have focused on the EET. It is often noted that EET is influenced/enabled by the extracellular components that form a stable and conductive matrix, including exopolysaccharides, nanowires, and extracellular cytochromes. Of these, the heme-containing cytochrome c enzyme is a crucial EET component because it provides both transport across the electrogenic bacterial outer membrane and subsequent transport to the final electron sink. Direct conductions via conductive nanowires is also understood to play an integral role in EET. Due to the complex interplay between metabolic/EET kinetics and the EAB composition, which change during EAB growth and maturation, it is hypothesized that the metabolic bottlenecks may change accordingly.