This review evaluates the feasibility of using microalgal culture for sustainable energy production, emphasizing microbial fuel cells (MFCs) and biophotovoltaics (BPVs). This study’s uniqueness is rooted in its thorough examination of recent developments (2014–present) in microalgal strain selection, bioreactor design, and electrode materials. Furthermore, this review combines microalga cultivation with wastewater treatment, highlighting its importance. Notably, it examines advanced methodologies, such as the use of genetic engineering to enhance microalgal traits, nanotechnology to optimize electrode efficacy, and artificial intelligence (AI) to optimize bioelectrochemical systems. In addition, this study identifies possible future research avenues by examining microalga–bacterium consortia and cascaded biobattery systems. Consequently, the incorporation of case studies illustrating microalga biobatteries’ practical applications in low-power devices and wastewater treatment underscores the technology’s promise. Similarly, this study examines significant problems with enhancing farming methods, reconciling cost and yield, and integrating renewable energy sources with the grid, offering vital insights for academics and policymakers. Ultimately, this review emphasizes the need for economical cultivation methods, waste stream utilization, and scalable bioreactor designs, thereby considerably advancing sustainable energy options.

Nowadays there is a growing trend towards carotenoids obtained from natural sources such as microalgae. Dunaliella salina is among the most significant natural sources of beta-carotene for commercial scale, which is used in many food industries. Enzymatic extraction of beta-carotene is one of the safe methods that ensure that the food product is not contaminated compared to ex-traction using solvents. In this study, beta-carotene was extracted using two methods: the organic solvent method by tetrahydrofuran and the enzymatic extraction using a bacterial lipase enzyme. The alga was exposed to different stress conditions (salinity/nitrogen) for increasing the beta-carotene production. The highest value of beta-carotene content was recorded in the extraction method using tetrahydrofuran (109.008 µg/mL at 2.5M NaCl/0.5 g/L KNO₃), compared to the extraction method using lipase enzyme (19.13 µg/mL at 1 mg/mL at 24 h exposure time). However, the beta-carotene yield slightly increased (21.4 µg/mL) in lipase enzyme extraction method for the algal samples exposed to more than 24 h under different conditions (3M NaCl/1g/L KNO₃). The results show that the enzymatic extraction method is less efficient in extracting beta-carotene compared to the tetrahydrofuran solvent extraction method, with the latter showing a higher content of extracted beta-carotene.