Fatty Acid Composition of Promising Microalgae for Biofuel Production: A Literature Review

Microalgae are promising third-generation feedstocks for renewable liquid biofuels because of their rapid growth, high areal productivity, ability to grow on non-arable land and saline or wastewater, and capacity to accumulate storage lipids rich in fatty acids suitable for conversion into biodiesel. This review synthesizes peer-reviewed literature (2021–2026) on the fatty acid composition of Chlorella vulgaris, Nannochloropsis spp., Scenedesmus spp., Botryococcus braunii, Phaeodactylum tricornutum and Haematococcus pluvialis. It examines fatty acid and triacylglycerol biosynthesis, cultivation effects on saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), and the relationship between fatty acid profiles and estimated biodiesel properties. The review also evaluates CRISPR/Cas-based engineering and machine-learning-assisted optimization, while emphasizing that reported genetic effects remain strain- and pathway-dependent. Microalgal biofuels may offer lower life-cycle greenhouse-gas emissions than fossil fuels in suitable systems, but they should not be described as inherently carbon-neutral: net emissions depend on cultivation energy, nutrient inputs, harvesting, extraction, conversion, and the source and fate of carbon. Nitrogen stress can increase lipid percentage while reducing biomass growth and overall lipid productivity. No single wild-type strain combines maximum productivity with a profile that satisfies all fuel-quality requirements; therefore, strain selection, process optimization and carefully validated engineering must be assessed together.