Technologies for extracting lipids from oleaginous microorganisms for biodiesel production

Pulsed electric field‐assisted extraction of valuable compounds from microorganisms

“…SCF temperature and pressure are above the critical point, thereby presenting properties that explain its greater ability to diffuse into the matrix than conventional organic solvents. Many studies deal with SC‐CO 2 extraction of carotenoids (Bustamante, Roberts, Aravena, & Del Valle, ; Hosseini, Tavakoli, & Sarrafzadeh, ; Machmudah, Shotipruk, Goto, Sasaki, & Hirose, ; Macías‐Sanchez, Serrano, Rodríguez, & de la Ossa, ; Mussagy, Winterburn, Santos‐Ebinuma, & Pereira, ) and lipids (Mendes, Reis, & Palavra, ; Sajilata, Singhal, & Kamat, ) from microalgae and yeasts (Hasan, Azhar, Nangia, Bhatt, & Panda, ; Lim, Lee, Lee, Haam, & Kim, ; Wang, Chen, Rakesh, Qin, & Lv, ). Co‐solvents that enhance the solubilizing power of SC‐CO 2 such as ethanol or vegetable oils are occasionally needed to increase the extraction yield (Lim et al., ).…”

Lipids from yeasts and fungi: physiology, production and analytical considerations

“…As far as the pretreatment of the wet microbial mass is concerned, before or simultaneously with the recovery of the microbial lipids, several types of operations have been proposed including but not limited to high-pressure homogenization (this method is currently used in large-scale operations in order highvalue protein to be recovered), steam explosion, bead milling, pulse electric field, ultrasound, osmotic shock, microwave-induced heating, subcritical water hydrolysis, supercritical fluid extraction, enzymatic hydrolysis, autolysis, chemical hydrolysis, employment of hydroxyl radicals that are generated from semiconductors (TiO 2 ) under UV-light irradiation and that can function as strong nonselective cell surface attackers, autoclaving at T = 120°C for variable time applications, etc. (for critical reviews see Davies 1988;Hammond and Glatz 1988;Wang et al 2012;Dong et al 2016). At pilot-scale operations (production of SCO in 150-L batch bioreactors using Apiotrichum curvatum ATCC 20509 in trials in which sweet rennet whey had been employed as substrate) various mechanical methods had been considered as the most appropriate ones for SCO extraction; thus, steam explosion, liquid shear (homogenization) and solid shear (bead milling) methods with or without simultaneous solvent extraction have been successfully employed on wet yeast biomass (Davies 1988).…”

Investigations on cell disruption of oleaginous microorganisms: Hydrochloric acid digestion is an effective method for lipid extraction

“…Biodiesel production from renewable resources has attracted much attention due to its environmental and economic sustainability . Vegetable oils, such as soybean oil, rapeseed oil and palm oil, along with animal fats and waste cooking oils are commonly used as feedstocks for biodiesel production . However, limited quantities of these conventional feedstocks cannot meet the growing market demand for biodiesel fuel .…”

“…Industrially, several downstream processing steps are needed to produce biodiesel from microbial cell biomass. These steps include cultivation, cell disruption, lipid extraction and fractionation, and transesterification . These processes are all essential; however, cell disruption is significant due to its large impact on the recovery yield of microbial lipid extraction , which determines the final lipid‐to‐biodiesel yield.…”