Enhancement of CO2 biofixation and bioenergy generation using a novel airlift type photosynthetic microbial fuel cell

Harnessing CO2 for sustainable bioelectricity: An engineered two-stage microbial co-culture approach with enhanced acetate metabolism

Climate change driven by rising atmospheric CO2 levels underscores the urgent need for sustainable energy solutions. This study investigates the dual potential of CO2 as a primary carbon source and acetate as an intermediate to simultaneously mitigate atmospheric CO2 levels and generate bioelectricity using microbial fuel cells (MFCs). A synthetic microbial co-culture was developed, combining Clostridium ljungdahlii for CO2 sequestration and Shewanella oneidensis MR-1 for bioelectricity production. To optimize MFC performance, S. oneidensis was modularly engineered to enhance acetate metabolism and electron transfer efficiency. Key modifications included upregulating ATP synthesis, introducing an ATP-independent acetate metabolic pathway, increasing NADH availability, and optimizing pili-based artificial conductive nanowires. These advancements achieved a maximum cell density (OD600 = 0.611), a record output voltage of 351.3 mV, and a record power density of 94.9 mW/m2 using acetate as the substrate. Furthermore, a two-stage biocatalytic system utilizing CO2 as the primary carbon source yielded an output voltage of 209.3 mV and a power density of 65.0 mW/m2. These results highlight the potential of engineered microbial co-culture for efficient CO2-based bioelectricity generation, offering a scalable and sustainable pathway toward carbon-neutral energy production.

Recent advances in swine wastewater treatment technologies for resource recovery: A comprehensive review

Swine wastewater (SW), characterized by highly complex organic and nutrient substances, poses serious impacts on aquatic environment and public health. Furthermore, SW harbors valuable resources that possess substantial economic potential. As such, SW treatment technologies place increased emphasis on resource recycling, while progressively advancing towards energy saving, sustainability, and circular economy principles. This review comprehensively encapsulates the state-of-the-art knowledge for treating SW, including conventional (i.e., constructed wetlands, air stripping and aerobic system) and resource-utilization-based (i.e., anaerobic digestion, membrane separation, anaerobic ammonium oxidation, microbial fuel cells, and microalgal-based system) technologies. Furthermore, this research also elaborates the key factors influencing the SW treatment performance, such as pH, temperature, dissolved oxygen, hydraulic retention time and organic loading rate. The potentials for reutilizing energy, biomass and digestate produced during the SW treatment processes are also summarized. Moreover, the obstacles associated with full-scale implementation, long-term treatment, energy-efficient design, and nutrient recovery of various resource-utilization-based SW treatment technologies are emphasized. In addition, future research prospective, such as prioritization of process optimization, in-depth exploration of microbial mechanisms, enhancement of energy conversion efficiency, and integration of diverse technologies, are highlighted to expand engineering applications and establish a sustainable SW treatment system.

Evaluating application of photosynthetic microbial fuel cell to exhibit efficient carbon sequestration with concomitant value-added product recovery from wastewater: A review

The emission of CO2 from industrial (24%) and different anthropogenic activities, like transportation (27%), electricity production (25%), and agriculture (11%), can lead to global warming, which in the long term can trigger substantial climate changes. In this regard, CO2 sequestration and wastewater treatment in tandem with bioenergy production through photosynthetic microbial fuel cell (PMFC) is an economical and sustainable intervention to address the problem of global warming and elevating energy demands. Therefore, this review focuses on the application of different PMFC as a bio-refinery approach to produce biofuels and power generation accompanied with the holistic treatment of wastewater. Moreover, CO2 bio-fixation and electron transfer mechanism of different photosynthetic microbiota, and factors affecting the performance of PMFC with technical feasibility and drawbacks are also elucidated in this review. Also, low-cost approaches such as utilization of bio-membrane like coconut shell, microbial growth enhancement by extracellular cell signalling mechanisms, and exploitation of genetically engineered strain towards the commercialization of PMFC are highlighted. Thus, the present review intends to guide the budding researchers in developing more cost-effective and sustainable PMFCs, which could lead towards the commercialization of this inventive technology.

The State-of-the-Art Functionalized Nanomaterials for Carbon Dioxide Separation Membrane

Nanocomposite membrane (NCM) is deemed as a practical and green separation solution which has found application in various fields, due to its potential to delivery excellent separation performance economically. NCM is enabled by nanofiller, which comes in a wide range of geometries and chemical features. Despite numerous advantages offered by nanofiller incorporation, fabrication of NCM often met processing issues arising from incompatibility between inorganic nanofiller and polymeric membrane. Contemporary, functionalization of nanofiller which modify the surface properties of inorganic material using chemical agents is a viable approach and vigorously pursued to refine NCM processing and improve the odds of obtaining a defect-free high-performance membrane. This review highlights the recent progress on nanofiller functionalization employed in the fabrication of gas-separative NCMs. Apart from the different approaches used to obtain functionalized nanofiller (FN) with good dispersion in solvent and polymer matrix, this review discusses the implication of functionalization in altering the structure and chemical properties of nanofiller which favor interaction with specific gas species. These changes eventually led to the enhancement in the gas separation efficiency of NCMs. The most frequently used chemical agents are identified for each type of gas. Finally, the future perspective of gas-separative NCMs are highlighted.