Combined enzymatic and mechanical cell disruption and lipid extraction of green alga Neochloris oleoabundans.

Dongqin Wang,Weimin Su,Yanqun Li,Xueqiong Hu,Min Zhong

doi:10.3390/ijms16047707

Abstract

Microalgal biodiesel is one of the most promising renewable fuels. The wet technique for lipids extraction has advantages over the dry method, such as energy-saving and shorter procedure. The cell disruption is a key factor in wet oil extraction to facilitate the intracellular oil release. Ultrasonication, high-pressure homogenization, enzymatic hydrolysis and the combination of enzymatic hydrolysis with high-pressure homogenization and ultrasonication were employed in this study to disrupt the cells of the microalga Neochloris oleoabundans. The cell disruption degree was investigated. The cell morphology before and after disruption was assessed with scanning and transmission electron microscopy. The energy requirements and the operation cost for wet cell disruption were also estimated. The highest disruption degree, up to 95.41%, assessed by accounting method was achieved by the combination of enzymatic hydrolysis and high-pressure homogenization. A lipid recovery of 92.6% was also obtained by the combined process. The combined process was found to be more efficient and economical compared with the individual process.

Highlights

Rapid-growing global consumption of fossil fuel has caused crude oil shortage and global warming and environment contamination
In order to increase the competitiveness of microalgal biodiesel, various researches have focused on its key processing stages, such as algal strain improvement [3], cell cultivation optimization [4,5,6,7,8], biomass harvest [9,10], oil extraction [11,12,13,14] and oil transesterification [15]
The disruption degree increased with the treating time, as shown in Figure 1a, but the increase was little after 30 min

Summary

Introduction

Rapid-growing global consumption of fossil fuel has caused crude oil shortage and global warming and environment contamination. Microalgae can capture parts of the solar energy and mitigate atmosphere CO2. They have much higher capability to produce biomass than terrestrial plants based on their higher rate-of-growth, as a kind of photosynthesis microorganism, and they can yield more oil under certain conditions than soybean and oil palm [1]. Algal oil extraction techniques can be briefly classified as dry and wet processing. The direct extraction of oil from the wet fresh algal cells avoids the major cost from the drying of biomass

Results

Discussion

Conclusion