Current Pretreatment/Cell Disruption and Extraction Methods Used to Improve Intracellular Lipid Recovery from Oleaginous Yeasts

Abstract

The production of lipids from oleaginous yeasts involves several stages starting from cultivation and lipid accumulation, biomass harvesting and finally lipids extraction. However, the complex and relatively resistant cell wall of yeasts limits the full recovery of intracellular lipids and usually solvent extraction is not sufficient to effectively extract the lipid bodies. A pretreatment or cell disruption method is hence a prerequisite prior to solvent extraction. In general, there are no recovery methods that are equally efficient for different species of oleaginous yeasts. Each method adopts different mechanisms to disrupt cells and extract the lipids, thus a systematic evaluation is essential before choosing a particular method. In this review, mechanical (bead mill, ultrasonication, homogenization and microwave) and nonmechanical (enzyme, acid, base digestions and osmotic shock) methods that are currently used for the disruption or permeabilization of oleaginous yeasts are discussed based on their principle, application and feasibility, including their effects on the lipid yield. The attempts of using conventional and “green” solvents to selectively extract lipids are compared. Other emerging methods such as automated pressurized liquid extraction, supercritical fluid extraction and simultaneous in situ lipid recovery using capturing agents are also reviewed to facilitate the choice of more effective lipid recovery methods.

Cutaneotrichosporon oleaginosus: A Versatile Whole-Cell Biocatalyst for the Production of Single-Cell Oil from Agro-Industrial Wastes

“…Each method is based on different mechanisms in order to disrupt cells and extract lipids. There are mechanical (bead mill, ultrasonication, homogenisation and microwave), chemical (acid or base digestions, osmotic shock, supercritical fluid extraction) and biological (enzymes) approaches for the disruption or permeabilization of oleaginous yeast membranes [127]. To date, each of them presents different advantages and disadvantages from the economic, environmental and/or technical points of view.…”

“…However, the use of these carcinogenic and hazardous chemicals severely limits the sustainability of the SCOs production to the commercial scale. Several studies investigated the substitution of chloroform and methanol with green solvents such as terpenes (p-cymene and d-limonene), esters (isoamyl acetate, butyl acetate, ethyl acetate), ethers (cyclopentyl methyl ether, 2-methyltetrahydrofuran), alcohols (isopropanol, ethanol) and amines (N-ethylbutylamine, N-dipropylamine and N, N-dimethylcyclohexylamine) [127,[129][130][131]. Although some of them (p-cymene, d-limonene, α-pinene, ethyl lactate, isopropanol and ethanol) were not suitable for replacing petroleum-based solvents, mainly due to technical and economic reasons, the potential use of green solvents has been demonstrated for several oleaginous yeasts with comparable extraction performance and no significant impact on the composition of lipids.…”

Aviation and maritime biofuels production via a combined thermochemical/biochemical pathway: A conceptual design and process simulation study

“…The estimated energy demand for conventional lipids purification techniques (i.e. bead milling, ultrasound, microwave) for Y. lipolytica is in the range of 115-194 MJ/kg of extracted oil [10]. However, with the novel steam explosion-based technologies that are proposed for the described value chain, the corresponding energy demands are expected to be remarkably lower.…”

In situ solid-liquid extraction enhances recovery of taxadiene from engineered S. cerevisiae cell factories

“…It is The copyright holder for this preprint this version posted July 12, 2021. ; https://doi.org/10.1101/2021.07.12.452013 doi: bioRxiv preprint acetone also enhanced the recovery of intracellular taxadiene, likely due to its effect on cellular permeability. The proposed SPA method is therefore an integrated bioprocess, eliminating the requirement for an additional unit operation for cellular lysis [1,48] or further metabolic engineering to introduce efflux pumps (e.g. outer membrane protein TolC) [49] to enhance the product secretion.…”