The ecological effects of algae-based fuel production have gained considerable attention in recent years due to the growing need for sustainable and renewable energy sources. Algae-based biofuels are considered a promising alternative to traditional fossil fuels, as they have the potential to reduce greenhouse gas emissions and mitigate some of the environmental challenges associated with conventional fuel production. This review aims to provide a comprehensive assessment of the ecological impacts associated with algae-based fuel production. Algae are known for their rapid growth and high oil content, which makes them an attractive feedstock for biofuel production. This advantage is often touted to reduce carbon emissions, as algae absorb carbon dioxide during photosynthesis and can potentially offset emissions from burning their oil-based biofuels. Additionally, algae cultivation can use non-arable land and wastewater, reducing pressure on valuable agricultural resources.

However, the ecological effects of algae-based fuel production are not without their challenges. It is crucial to evaluate and manage potential negative consequences, such as nutrient runoff and the introduction of non-native algae species in natural ecosystems. Algae cultivation requires water, nutrients, and suitable environmental conditions, which can lead to competition for freshwater resources, eutrophication, and potential harm to aquatic ecosystems. The use of synthetic chemicals in algae cultivation, such as pesticides and fertilizers, can also have adverse ecological impacts. Furthermore, the land use and infrastructure required for large-scale algae cultivation should be carefully planned to prevent habitat destruction and loss of biodiversity. The energy and resources consumed during the cultivation, harvesting, and processing of algae into biofuels should be analysed to assess their environmental footprint.

This review will examine existing research and literature to provide a comprehensive evaluation of the ecological effects of algae-based fuel production. By synthesizing the current knowledge, it aims to shed light on the trade-offs and potential solutions for mitigating the environmental impacts associated with this promising biofuel source. The conclusions drawn from this review will help guide future research and development in the field of algae-based biofuels, with the goal of minimizing their negative ecological effects while harnessing their environmental benefits. Concerns about the rapid depletion of fossil fuels, energy security, climate change due to global warming, environmental pollution, and faster increase of fossil fuel prices have drawn attention to researchers, the scientific community, and government policymakers to develop alternative energy sources for reducing dependence on fossil fuel. In recent years, microalgae culture has received significant attention due to its potential application for bioenergy production, wastewater treatment, industrial CO₂ removal, and production of biochemical compounds that can be used for human and animal health and other benefits. However, large-scale microalgae production and their processing for producing various products and by-products could have environmental impacts beyond energy consumption in the microalgal production process. This article has reviewed the environmental effects of microalgae-based biofuel production on water resources and quality, eutrophication, biodiversity, waterborne toxicants, algal toxicity, wastewater remediation or treatment, waste generation, and greenhouse gas land-use changes, and genetically engineered microalgae.