The current fossil fuel reserves are not sufficient to meet the increasing demand and very soon will become exhausted. Pollution, global warming, and inflated oil prices have led the quest for renewable energy sources. Macroalgae (green, brown, and red marine seaweed) is gaining popularity as a viable and promising renewable source for biofuels production. Numerous researches have been conducted to access the potential of macroalgae for generating diverse bioproducts such as biofuels. The existence of components such as carbohydrates and lipids, and the lack or deficiency of lignin, create macroalgae an enviable feedstock for biofuels generation. This review briefly covers the potential macroalgal species promoting the production of biofuels and their cultivation methods. It also illustrates the biofuel generation pathway and its efficiency along with the recent techniques to accelerate the product yield. In addition, the current analysis focuses on a cost-effective sustainable generation of biofuel along with commercialization and scaleup.

The objective of this study was to evaluate the effect of surfactant on disperser homogenization pretreatment for macroalgae (Ulva intestinalis) to enhance biogas production. The macroalgae are subjected to surfactant coupled disperser pretreatment, which enhanced the liquefaction and improved the biomethane production. The outcome of this study revealed that 10,000 rpm at 20 min with a specific energy input of 1748.352 kJ/ kg total solids (TS) are the optimum conditions for surfactant disperser pretreatment (SDP), which resulted in the liquefaction rate of 20.08% with soluble organics release of 1215 mg/L and showed a better result than disperser pretreatment (DP) with a liquefaction rate of 14%. Biomethane production through the SDP method was found to be 0.2 g chemical oxygen demand (COD)/g COD, which was higher than DP (0.11 g COD/g COD). SDP was identified to be a synergetic pretreatment method with an energy ratio and net profit of about 0.91 and 104.04 United States dollars (USD)/ton, respectively.

High organic pollutant load and salinity pose major challenges for the biological treatment of industrial wastewater. This study evaluated an air-cathode microbial fuel cell (AC-MFC) inoculated with halophilic microorganisms for the simultaneous treatment of phenol-contaminated saline industrial wastewater and bioelectricity generation. The AC-MFC was operated at organic loads (OLs) of 1.2, 2.5, 3.2, 4.8, 6.2 and 8.6 g chemical oxygen demand (COD)/L, with optimum performance at 6.2 g COD/L. In optimal conditions, the system achieved a maximum voltage of 803 mV, power density of 460.6 mW/m², current density of 573.6 mA/m², and total and soluble COD removal efficiencies of 90% and 89%, respectively. Complete phenol degradation was achieved within 8 days. High-throughput sequencing revealed dominant halophilic taxa, including Ochrobactrum, Marinobacter, Bacillus and Stenotrophomonas, which may contribute to pollutant degradation and extracellular electron transfer. A Random Forest regression model implemented using Python/scikit-learn was further developed using OL and operational time as input variables to predict treatment and electrochemical performance. The model identified 6.2 gCOD/L as the optimum OL, consistent with the experimental results. Overall, inoculation of halophilic consortium coupled with AC-MFC technology demonstrates potential for simultaneous treatment of saline phenolic wastewater and bioelectricity generation, while artificial intelligence provides a useful tool for process optimization.