Microalgae–Bacteria Consortia: A Review on the Degradation of Polycyclic Aromatic Hydrocarbons (PAHs)

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are considered as import contaminants portraying diverse ecological and public health apprehension due to their properties such as water solubility, toxicity, bioaccumulation potential and recalcitrant nature. Due to their contrary impact on the human wellbeing and other organisms in the biosphere, research is in progress to remove PAHs from the environment. Several physicochemical methods can be used for the removal of PAHs; however, its bioremediation using microorganisms is a benign and ecofriendly approach. Various strains of bacteria and microalgae are capable to potentially degrade or transform PAHs through their indigenous metabolic pathways. However, their biodegradability potential hindered by the cytotoxic effect of petroleum hydrocarbons, unfavorable environmental conditions, metabolic constrains, hydrocarbon composition, concentration, type and number of microorganisms. During the last decade, different microalgae species have been reported capable of biodegrading PAHs. Moreover, the interaction between microalgae and bacteria PAH metabolic pathways overcomes some rate limiting step(s) observed in single species. Thus, an alternative paradigm "Microalgae-Bacteria Consortia" is emerging as a new strategy to be adopted for the efficient detoxification and removal of the PAH pollutants. This review article aimed to provide an update of the current knowledge on the toxic effects of PAHs in various organisms as well as the symbiotic interactions between different bacteria and microalgae species in the degradation/transformation of PAHs. In addition, environmental factors are highlighted to elucidate how PAHs influence the growth of microalgae within a symbiotic framework with bacteria counterpart. The ultimate outcome of this paper can be beneficial to expedite the progress of new research into the bioremediation of PAHs from the contaminated environments.

Enhanced biodegradation of phenanthrene and anthracene using a microalgal-bacterial consortium

“…For the biodegradation of resistant PAHs, researchers are currently concentrating on microalgae bacterium consortia. This co-culturing method, which combines bacteria and microalgae, is more advantageous than employing just one species and is thus more promising ( Ahmad, 2021 ; García et al, 2021 ). The organisms coexist in a symbiotic relationship in a microalgae bacteria consortium, where microalgae provide oxygen during photosynthesis that may promote bacterial development.…”

Prospects for Combined Applications of Nanostructured Catalysts and Biocatalysts for Elimination of Hydrocarbon Pollutants

“…In the absence of O 2 , the aromatic ring is destroyed by the action of reductases and other electron acceptors. The biodegradation process is usually slowed down due to the cytotoxicity of hydrocarbons and their high concentrations due to unfavorable environmental conditions or the presence of metabolic restrictions [78][79][80].…”

Bioremediation of common high-molecular-weight polycyclic aromatic hydrocarbons: a bibliometric analysis based on Web of Science via VOSviewer

“…In recent years, bibliometric analysis has been widely applied across various disciplines, such as environmental science, medicine, and engineering. It has assisted researchers in elucidating knowledge foundations, identifying research hotspots, and exploring emerging directions within speci c elds (Ahmad et al, 2022;Araujo et al, 2020;Goncalves et al, 2019). VOSviewer is a software tool designed for bibliometric analysis and scienti c visualization.…”

“…For example, fungal-bacterial cocultures(Bankole et al, 2022) and physically adsorbed synergistic biodegradation techniques (immobilization)(Du et al, 2023) were explored to enhance degradation e ciency.Research on in uencing factors. Some studies examined the effects of different environmental and nutritional parameters on degradation, including studies on river sediments, contaminated soils, oceans, mangroves, and other environmental media(Acer et al, 2021;Ahmad, 2022;Andersson et al, 2003;Bankole et al, 2022). These studies explored factors such as oxygen content(Acer et al, 2021), culture conditions, nutrients(Agrawal et al, 2018;Ahmad, 2022), and soil physicochemical properties(Andersson et al, 2003) that in uence the degradation process.…”