biodiesel production from algae via transesterification reaction: challenges and opportunities (review)

This study tries to review the methods and stages of biodiesel production from the extracted oil of algae through a transesterification reaction. biodiesel is a clean, renewable, biodegradable, and eco-friendly fuel. algae are considered the third-generation and the most promising biodiesel feedstock because of their advantages including that microalgae have the potential to produce 25–220 times higher triglycerides than terrestrial plants and the growth rate of algae is approximately 20- 30 times faster than food-yielding crops. algae can grow almost in all kinds of water such as fresh or waste waters and on non-arable and marginal land and engine performance and exhaust emission of microalgae biodiesel investigated. due to the higher oil content in microalgae than macroalgae, it is a better feedstock for biodiesel production. this work studied the steps of biodiesel production from microalgae including cultivation of microalgae, harvesting, oil extraction, and especially how to create biodiesel from microalgae biomass through transesterification reaction by focusing on the kinds of catalysts that have been used for microalgal biodiesel production studied. transesterification reactions are commonly catalyzed by acids or bases as chemical catalysts or carried out in the presence of enzyme catalysts as biocatalysts. also, the advantages of using heterogeneous catalysts compared to homogeneous ones were investigated. many efforts have been made to commercialize algae biodiesel but the high cost of producing algae and extracting its oil is challenging and it will still take some time before algal biofuels become a commercial reality in iran and all the world.