## 5 Conclusions  
BESs have seen significant advancements in the past decade due to their emerging role as sustainable technologies for concurrent electricity production, wastewater treatment, and CO\({}_{2}\) fixation. BESs also offer excellent prospects for the clean and efficient production of high-value fuels and chemicals using microorganisms. A noteworthy type of BES is the mMFC, which generates energy by exploiting the capture of CO\({}_{2}\) for biomass and lipid production. Building upon the extensive comparison of mMFC configurations and parameters presented throughout this review, it becomes evident that achieving significantly enhanced efficiency in mMFC technology requires a multifaceted approach. Key areas of focus include increasing power densities, reducing internal resistance, enhancing current density, and producing high-value products. In this sense, the application of unconventional wastewater and the development of technologies that integrate anodic and cathodic systems could be a strategy in future research in the frame of the biorefinery approach. Other important research areas are development of carbon-based electrodes with metal catalyzers that maximize surface area and conductivity; optimization of dual camera configurations that minimize internal resistance; selection of microalgae strains with high oxygen production and improved electron transfer capacity; and meticulously control of operational parameters like light, CO\({}_{2}\) and nutrient specific for each strain. Additionally, understanding the mechanisms of electron transfer, developing novel reactor designs and architectures, and scaling up reactor volume and operation time are crucial. Despite the significance and efforts to advance mMFC technology, limitations still exist that hinder its widespread use, such as low Coulombic Efficiency and a limited understanding of the bioelectrochemical mechanisms behind electron transfer between algae and electrodes. It is vital to comprehend the conditions provided by mMFCs concerning electron capture, lipid synthesis, and accumulation. New studies should utilize modern techniques to explore the complex world of metabolism, aiming to enhance our understanding of the metabolic characteristics of microalgae, with the goal of promoting lipid formation in mMFCs.  
Conceptualization, C.M.-V., J.C.Q.D. and F.J.F.-M.; methodology, C.M.-V. and F.J.F.-M.; software, C.M.-V.; validation, C.M.-V. and F.J.F.-M.; formal analysis, C.M.-V., J.C.Q.D. and Y.A.Y.; investigation, [PERSON]-V.; resources, [PERSON]-V. and J.C.Q.D.; data curation, [PERSON]-V., J.C.Q.D. and Y.A.Y.; writing--original draft preparation, [PERSON]-V., J.C.Q.D., Y.A.Y. and [PERSON]-[PERSON]; writing--review and editing, [PERSON]-V., J.C.Q.D. and F.J.F.-M.; visualization, [PERSON]-V.; supervision, [PERSON]-M.; project administration, [PERSON]-V. and J.C.Q.D.; funding acquisition, [PERSON]-V. and J.C.Q.D. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by Ministerio de Ciencia, Tecnologia e Innovacion of Colombia, by research contract No. 80740-177.2019. [PERSON] wants to acknowledge the Ministerio de Ciencia, Tecnologia e Innovacion of Colombia for studentship (Grant No. 727 of 2015).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** No new data were created or analyzed in this study.  
**Conflicts of Interest:** The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.