Fractionation process for the protective isolation of ergosterol and trehalose from microbial biomass

Abstract

A new process is described for the two phase extraction of ergosterol and trehalose from microbial biomass. Baker's yeast was used as a model organism to develop the method, which was then applied for extracting 13 oleaginous microbes. Major findings of the study were that the ergosterol content was not dependent on intracellular oil content and that 1-butanol and alkaline pH were needed to protect ergosterol. Saponification for 3−4 hours at 85−100 ºC followed by extraction of the reaction mixture with toluene gave the maximal ergosterol yield.Trehalose was stable at this temperature and remained in water solution, but the maximal yield was obtained after a shorter reaction time at lower alkalinity. Although trehalose alone is stable at alkaline pH, extraction yields of trehalose from yeast decreased with increasing alkalinity.This finding led us to propose a two-step process in which trehalose is separated in the first step and ergosterol in the second. The possibility to apply this method to fractionate oleaginous microbes in process scale is discussed from technical viewpoints.

Analysis of the tendency for the electronic conductivity to change during alcoholic fermentation

“…Determination of the cell mortality, ergosterol and malondialdehyde concentration. The mortality, ergosterol concentration 25 and malondialdehyde (MDA) 26 concentration of the yeast cells in the fermentation broth were determined at 56, 58, 60, 62 and 64 h. The morphological changes of the cells were observed by microscope.…”

Development of a Methodology for Estimating the Ergosterol in Meat Product-Borne Toxigenic Moulds to Evaluate Antifungal Agents

“…A reversed-phase column (C 18 ) was selected for the HPLC-FLD/DAD detection method, due to its good peak resolution [ 23 , 27 ]. Firstly, the selection of the most appropriate mobile phase was performed ( Table S1, Supplementary Materials ).…”

“…A total of six methods for extracting mould ergosterol were evaluated. They consisted of two previously reported ones [ 23 , 24 ] and modifications of such methods ( Table 1 ).…”

“…Ergosterol is not water soluble, but appropriately dissolves in acetone and ethanol [ 22 ]. Accordingly, different kinds of organic solvents like butanol and hexane have been used for ergosterol extraction [ 23 , 24 ]. The analytical methods for its detection have been usually based on high-performance liquid chromatography (HPLC), with methanol as eluent [ 23 , 24 , 25 ], or gas chromatography (GC) with mass spectrometry detection [ 26 ].…”

“…Accordingly, different kinds of organic solvents like butanol and hexane have been used for ergosterol extraction [ 23 , 24 ]. The analytical methods for its detection have been usually based on high-performance liquid chromatography (HPLC), with methanol as eluent [ 23 , 24 , 25 ], or gas chromatography (GC) with mass spectrometry detection [ 26 ]. Concretely, HPLC coupled with a UV detector is the most used method for analysing ergosterol [ 27 , 28 ], since it is easy to handle and has lower maintenance costs and technical requirements than other detectors or chromatographic techniques [ 29 , 30 ].…”