Chlorophyll is an essential compound in many everyday products. It is used not only as an additive in pharmaceutical and cosmetic products but also as a natural food colouring agent. Additionally, it has antioxidant and antimutagenic properties. This review discusses the process engineering of chlorophyll extraction from microalgae. Different chlorophyll extraction methods and chlorophyll purification techniques are evaluated. Our preliminary analysis suggests supercritical fluid extraction to be superior to organic solvent extraction. When compared to spectroscopic technique, high performance liquid chromatography was shown to be more accurate and sensitive for chlorophyll analysis. Finally, through capture and wastewater treatment, microalgae cultivation process was shown to have strong potential for mitigation of environmental impacts. 1. Background Microalgae are microscopic unicellular organisms capable to convert solar energy to chemical energy via photosynthesis. They contain numerous bioactive compounds that can be harnessed for commercial use. Marine microalgae in particular have unique biochemical characteristics not found in higher plants [1]. Microalgae are usually cultivated in open ponds or photobioreactors. The cultivation process requires carbon dioxide, light, water and other nutrients which facilitate the photosynthetic process. Microalgal cultivation captures greenhouse gas CO2 while simultaneously produces biomass containing high-value consumer products. Chlorophyll is one of the valuable bioactive compounds that can be extracted from microalgal biomass. It is used as a natural food colouring agent and has antioxidant as well as antimutagenic properties. The process of extracting chlorophyll from marine microalgae begins with dewatering and desalting the highly dilute microalgal culture (biomass concentration =？？0.1–1%？w/v). Chlorophyll is then extracted from the dried biomass by organic solvent extraction or supercritical fluid extraction. This process is followed by a fractionation step to separate the chlorophyll pigments and derivatives. Many studies have been carried out to optimize chlorophyll extraction and fractionation from microalgae. This review focuses on the entire chlorophyll production process beginning from microalgae cultivation to chlorophyll fractionation and purification. 1.1. Chlorophyll Classification There are two main types of chlorophyll, chlorophyll and chlorophyll . However, exposure of chlorophyll molecules to weak acids, oxygen or light accelerated their oxidation and resulted in the formation of numerous
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