Lipid Extraction Maximization and Enzymatic Synthesis of Biodiesel from Microalgae

I.M Rizwanul Fattah,A S Silitonga,Irfan Anjum Badruddin,T.M Yunus Khan,M Mofijur,M.Y Noraini,T.M.I Mahlia,Hwai Chyuan Ong

doi:10.3390/app10176103

Abstract

Microalgae has received overwhelming attention worldwide as a sustainable source for energy generation. However, the production of biofuel from microalgae biomass consists of several steps, of which lipid extraction is the most important one. Because of the nature of feedstock, extraction needs special attention. Three different methods were studied to extract algal oil from two different algae variant, Chlorella sp. and Spirulina sp. The highest percentage oil yield was obtained by ultrasonication (9.4% for Chlorella sp., 6.6% for Spirulina sp.) followed by the Soxhlet and solvent extraction processes. Ultrasonication and Soxhlet extraction processes were further optimized to maximize oil extraction as solvent extraction was not effective in extracting lipid. For ultrasonication, an amplitude of 90% recorded the highest percentage yield of oil for Spirulina sp. and a 70% amplitude recorded the highest percentage yield of oil for Chlorella sp. On the other hand, for Soxhlet extraction, a combination of chloroform, hexane, and methanol at a 1:1:1 ratio resulted in the highest yield of algal oil. Afterward, the crude algae oil from the ultrasonication process was transesterified for 5 h using an immobilized lipase (Novozyme 435) at 40 °C to convert triglycerides into fatty acid methyl ester and glycerol. Thus, ultrasonic-assisted lipid extraction was successful in producing biodiesel from both the species.

Highlights

Depleting oil reserves, increased energy dependency, and the environmental impact of fossil fuel use has led to research on sustainable energy resources with a cleaner footprint [1,2,3]
This study investigated two different microalgae species, Chlorella sp. and Spirulina sp., which are widely available in Malaysia and the southeast Asian region and possess low lipid contents
The dried microalgae species used in this study were Chlorella sp. and Spirulina sp., which were obtained from a local supplier

Summary

Introduction

Depleting oil reserves, increased energy dependency, and the environmental impact of fossil fuel use has led to research on sustainable energy resources with a cleaner footprint [1,2,3]. In particular biodiesel, is a feasible diesel fuel replacement because it can be directly employed without modification of the engine structure [4,5,6]. A review of life cycle analysis on liquid biofuel systems has concluded that conventional biofuels (from grains and seeds) can provide moderate greenhouse gas (GHG) reduction benefits in measures, Appl. Sci. 2020, 10, 6103 such as ‘per GJ fossil fuel displaced’, ‘per ha land use’, etc., owing to high land requirements [10]

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Conclusion