As of 2024, approximately 81.5% of global energy consumption is still derived from non-renewable fossil fuels, such as coal, oil, and natural gas. This highlights the urgent need to transition to alternative energy sources amid the escalating climate crisis. Cyanobacteria and microalgae have emerged as promising biocatalysts in microbial fuel cells (MFCs) for eco-friendly energy production, owing to their photosynthetic abilities and resilience in regard to various environmental conditions. This review explores the potential of cyanobacteria and microalgae to drive bioelectricity generation via metabolic and extracellular electron transfer processes, leveraging their ability to fix carbon and nitrogen, while thriving in challenging environments. Bioengineering and electrode design advances are integrated to enhance the electron transfer efficacy and constancy of cyanobacteria-based MFCs. This approach addresses the growing demand for carbon-neutral energy and can be applied to wastewater treatment and bioremediation scenarios. By synergizing biological innovation with sustainable engineering techniques, this review establishes cyanobacteria and microalgal-driven MFCs as a scalable and eco-friendly platform for next-generation energy systems. The findings lay the groundwork for further exploration of the role of cyanobacteria and microalgae in bridging the gap between renewable energy production and environmental stewardship.

Achieving high energy density while maintaining high power density and long cycle life in supercapacitors, particularly in supercapatteries (SCs), through a thermally stable, greener ionic liquid approach remains a significant challenge for an advanced energy storage application. In this work, we prepared high conductive and high charge storage capability bimetallic transition metal molybdate [Ag₂Mo₂O₇ (AgM)], synergistic with reduced graphene oxide (rGO) coated on nickel foam (AgM/rGO/NF). The physio-chemical characterization revealed a ball-like cluster morphology wrapped in rGO nanosheets and a spinel-type cubic structure using scanning electron microscopy (FE-SEM) displays and X-ray diffraction (XRD) analyses. Further, the electrochemical performance of AgM/rGO/NF electrode achieved a remarkable specific C_sp value of 573.63 F/g at a current density of 1.0 A/g in 3 M KOH electrolyte. An asymmetric SCs (ASCs) device was fabricated using AgM/rGO/NF as the positive and rGO as the negative electrodes, achieving a wide potential window of 1.3 V. The ASC demonstrated an energy density of 16.71 Wh/kg at a power density of 642.98 W/kg, highlighting AgM/rGO/NF’s potential as an advanced electrode material for energy storage applications.

A novel composite material consisting of cerium dioxide (CeO₂), silica (SiO₂), and mesoporous carbon (CMK-3) was developed for supercapacitor electrodes. The composite’s synthesis involved a high-surface-area porous carbon combined with CeO₂ and SiO₂. The resulting material was characterized by a high specific capacitance due to its mesoporous structure and enhanced dispersion CeO₂ and SiO₂. The effects of different types of CeO₂ and SiO₂ are also discussed. Both CeO₂ and SiO₂ components offer advantages such as abundance, low costs, and excellent catalytic properties. The composite’s structure improves CeO₂ nanofiber (CeO₂ NF) dispersion and reduces impedance through rapid redox reactions. The influence of the CeO₂/SiO₂/CMK-3 ratio on specific capacitance was investigated. The optimized composite electrode demonstrated a significantly improved specific capacitance, 2.6 times higher than that of the pristine mesoporous carbon electrode. This work highlights the potential of CeO₂/SiO₂/CMK-3 composites for energy storage applications and underscores the importance of optimizing component ratios and morphology for improved supercapacitor performance.

The inclusion of adsorption thermodynamic analysis and performance benchmarking with existing adsorbents reinforces both the theoretical significance and practical applicability of this study. The modified rubber-derived carbon demonstrated a remarkably high DBT adsorption capacity of 254.45 mg/g. These results establish it as a promising alternative to conventional materials such as commercial activated carbon, zeolites, and even metal–organic framework materials. In addition to confirming the superior performance of the adsorbent, the findings provide a deeper understanding of the DBT adsorption mechanism and offer a solid scientific basis for large-scale fuel desulfurization applications. This research highlights the potential of transforming end-of-life tire waste into value-added functional materials and contributes to the advancement of sustainable and efficient desulfurization technologies. Future work should focus on optimizing surface functionalization and regeneration strategies to further improve long-term adsorption stability and practical deployment.

This study assesses the aptitude of heterocystous cyanobacterial strain Dolichospermum spiroides MBDU 903 in integrated wastewater treatment and biofuel production at a laboratory scale. The efficiency of the strain was assessed based on pigment accumulation, growth kinetics, nutrient remediation efficiency, and biodiesel fuel quality. The results demonstrated that the biomass productivity of D. spiroides MBDU 903 ranged from 69.27 to 167.08 mg L⁻¹ day⁻¹ across various nutrient regimes, achieving a maximum lipid content of 31% (w/w). Cultivation in municipal wastewater with BG11+ (50% v/v) yielded the highest pigment production biomass. The physicochemical properties of the derived biodiesel were estimated from gas chromatography-derived fatty acid methyl ester (FAME) profiles. Furthermore, the biorefinery potential was explored as a proof-of-concept by fermenting the post-transesterification residual biomass with Saccharomyces cerevisiae, yielding 14.5 mg/g of bioethanol from the pretreated residue. While a 10 L pilot-scale trial was conducted, significant productivity drops suggest that further optimization is required to bridge the gap between laboratory results and practical application. This study provides a baseline evaluation of the dual-fuel potential of a heterocystous cyanobacterium under wastewater-integrated conditions.

Cyanobacteria are prokaryotic group of ancient, morphologically varied organisms that utilize oxygen for photosynthesis, contributing significantly to global carbon and nitrogen fixation while improving crop quality. With the rising population and increasing demand for food, advancing agricultural productivity is essential. Therefore, ongoing research is crucial for boosting crop development and increasing food output. According to previous studies, cyanobacteria are among the best sources for crop development and enhancement. In addition, the Azolla-Anabaena are environmentally significant organisms, as they can be used in bioremediation, the reclamation of infertile land, mosquito control, and the sustainable intensification of animal husbandry by serving as high-quality fodder. Furthermore, they play a role in bioenergy development, emphasizing bio-oil and biodiesel production. The applications of these cyanobacterial systems extend far beyond traditional agriculture, presenting opportunities for innovation in the bioenergy sector. This review provides in-depth information on the critical role of cyanobacteria in ecological restoration and socioeconomic improvement, offering valuable insights for advancing sustainable agricultural practices and renewable energy solutions. In addition, the review highlights broader applications of the Anabaena-azollae symbiosis in nitrogen fixation, plant growth, and animal feed, underscoring their multifaceted nature and vast potential for practical use.