FTIR Spectroscopy for Evaluation and Monitoring of Lipid Extraction Efficiency for Oleaginous Fungi

Abstract

To assess whether Fourier Transform Infrared (FTIR) spectroscopy could be used to evaluate and monitor lipid extraction processes, the extraction methods of Folch, Bligh and Lewis were used. Biomass of the oleaginous fungi Mucor circinelloides and Mortierella alpina were employed as lipid-rich material for the lipid extraction. The presence of lipids was determined by recording infrared spectra of all components in the lipid extraction procedure, such as the biomass before and after extraction, the water and extract phases. Infrared spectra revealed the incomplete extraction after all three extraction methods applied to M.circinelloides and it was shown that mechanical disruption using bead beating and HCl treatment were necessary to complete the extraction in this species. FTIR spectroscopy was used to identify components, such as polyphosphates, that may have negatively affected the extraction process and resulted in differences in extraction efficiency between M.circinelloides and M.alpina. Residual lipids could not be detected in the infrared spectra of M.alpina biomass after extraction using the Folch and Lewis methods, indicating their complete lipid extraction in this species. Bligh extraction underestimated the fatty acid content of both M.circinelloides and M.alpina biomass and an increase in the initial solvent-to-sample ratio (from 3:1 to 20:1) was needed to achieve complete extraction and a lipid-free IR spectrum. In accordance with previous studies, the gravimetric lipid yield was shown to overestimate the potential of the SCO producers and FAME quantification in GC-FID was found to be the best-suited method for lipid quantification. We conclude that FTIR spectroscopy can serve as a tool for evaluating the lipid extraction efficiency, in addition to identifying components that may affect lipid extraction processes.

Coconut (Cocos nucifera L.) Lipids: Extraction and Characterization

“…1 . Some of these peaks are slightly shifted from the characteristic band of lipids reported by Wolkers (28), Dean et al, (29) and Forfang et al, (30) it is assumed due to the interfering interaction between neighboring lipids such as acyl chain conformation and formation of hydrogen bonding.…”

Development of Rhodotorula mucilaginosa strain via random mutagenesis for improved lipid production

“…However, efficient lipid extraction is often achieved with the combination of solvent extraction and pretreatment steps that disrupt the cell structure (Forfang et al, 2017). Acid hydrolysis prior to extraction weakens the yeast cell wall, causing monomeric sugars to be released into the aqueous phase, enabling the solvents to bind the lipids directly (Yu et al, 2014;Dong et al, 2016;Roux et al, 2017).…”

“…Thus, further research on optimizing lipid production and the use of industrial or agricultural waste as the substrate for strain improvement are recommended. A suitable lipid extraction method needs to be applied on different species as the lipid extraction efficiency is affected by the type of microbial biomass (Lee et al, 2010;Forfang et al, 2017).…”

Lipids detection and quantification in oleaginous microorganisms: an overview of the current state of the art

“…Flow-cytometry and Fourier transform infrared spectroscopy (FTIR) supported by multivariate analysis, have been proposed as fast and reliable means to monitor and quantify lipids over time in the oleaginous yeasts Cryptococcus curvatus, Rhodosporidium toruloides, and Lipomyces starkeyi [38,40]. Microtiter plate cultivation systems combined with FTIR have also been used as a high-throughput online platform for screening of oleaginous filamentous fungi [106] and to evaluate the efficiency of lipid extraction processes in oleaginous fungi [107]. FTIR analysis of various microorganisms and their sample preparation are presented in Table 5.…”