• Energy Research

The increasing population density and industrialization are adversely affecting the environment globally. The contamination of the soil, agricultural lands, and water bodies with petroleum wastes and other hydrocarbon pollutants has become a serious environmental concern as perceived by the impacts on the aquatic and marine ecosystem. Various investigations have provided novel insights into the significant roles of microbial activities in the cleanup of hydrocarbon contaminants. However, the burden of these pollutants is expected to increase many folds in the next decade. Therefore, it is necessary to investigate and develop low-cost technologies rapidly, focusing on eco-sustainable development. An understanding of the details of biodegradation mechanisms paves the way for enhancing the efficiency of bioremediation technology. The current article reviews the applicability of various bioremediation processes, biodegradation pathways, and treatments, and the role of microbial activities in achieving efficient eco-sustainable bioremediation of hydrocarbon pollutants. It is envisaged that an integrated bioremediation approach, including biostimulation and bioaugmentation is preferably advocated for the cost-effective removal of toxic petroleum hydrocarbons and their derivatives.

This study aims to enhance lipid and biofuel productivity from Chlorella minutissima with hematite (α-Fe2O3) nanoparticles (IONPs) as a growth stimulant. The IONPs were synthesized using chemical method and characterized using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) analysis to confirm their structure and composition. The experimental setup involved inoculating various concentrations of IONPs (10, 20, and 30 mg·L−1) into the microalgal BG-11 growth medium to evaluate their impact on microalgal growth and biodiesel production. Results of this study showed that a concentration of 10 mg·L−1 of IONPs significantly increased the biomass concentration to 508.1 mg·L−1 over a 20-day cultivation period, achieving the highest biomass production rate of 31.7 mg·L−1·d−1 at this concentration. The lipid extracted from the microalgal biomass was subsequently transesterified into biodiesel. Key biodiesel properties, such as cetane number, calorific value, density, and viscosity, were measured to assess fuel quality. The findings demonstrate that incorporating hematite nanoparticles into the microalgal growth medium can significantly boost both lipid content and overall growth, thereby improving biodiesel production. This study suggests that the use of α-Fe2O3 nanoparticles presents a promising approach for scalable and sustainable biofuel production from microalgae.