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Conversion of lignocellulose and crude glycerol to lipids by oleaginous yeasts - physiology and diversity

Chmielarz, Mikolaj (2021). Conversion of lignocellulose and crude glycerol to lipids by oleaginous yeasts - physiology and diversity. Diss. (sammanfattning/summary) Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880
ISBN 978-91-7760-784-7
eISBN 978-91-7760-785-4
[Doctoral thesis]

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Abstract

Oleaginous yeasts are organisms capable of accumulating lipids. Some of them can grow on various substrates considered to be too toxic for many other microorganisms. Crude glycerol (CG) and hemicellulose hydrolysate (HH) are two examples of such substrates.
Lipid quantification by extraction is a time-consuming process which requires usage of organic solvents and strong acids when applied on yeasts. To address this, we developed a new method using Fourier-transform near infra-red (FT-NIR) spectroscopy to quantify lipids within yeast cells. The resulting model for Rhodotorula toruloides had a R2 of 98% and a 5% error in prediction when compared with the traditional lipid extraction method. The method was used to follow lipid formation kinetics in subsequent experiments.
Out of 27 tested oleaginous yeast strains, less than half could grow on crude glycerol. Two strains, R. toruloides CBS14 and Rhodotorula glutinis CBS3044 grew well on this substrate, and were even activated when it was supplemented with hemicellulose hydrolysate (producing up to 12.5 g/L lipids). RNA sequencing in R. toruloides CBS14 revealed increased transcription of genes related to energy metabolism, mitochondrial enzymes and genes involved in protein synthesis. There were only little differences in genes related to glycerol metabolic pathways. Probably, cells grown in CGHH have a more efficient energy metabolism and thus, more ATP to build up biomass and lipids, and to take up substrate from the medium.
The new method for lipid quantification and the identified regulated genes can be the basis for further manipulations of yeast metabolism to reach sustainable microbial oil production from residual substrates.

Authors/Creators:Chmielarz, Mikolaj
Title:Conversion of lignocellulose and crude glycerol to lipids by oleaginous yeasts - physiology and diversity
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2021
Number:2021:53
Number of Pages:62
Publisher:Department of Molecular Sciences, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-7760-784-7
ISBN for electronic version:978-91-7760-785-4
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Article category:Other scientific
Version:Published version
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Biochemistry and Molecular Biology
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Microbiology (Microbiology in the medical area to be 30109)
Keywords:oleaginous yeast, crude glycerol, lignocelluloses, FT-NIR, lipids
URN:NBN:urn:nbn:se:slu:epsilon-p-112923
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-p-112923
ID Code:24912
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Department of Molecular Sciences
Deposited By: SLUpub Connector
Deposited On:17 Aug 2021 06:57
Metadata Last Modified:19 Aug 2021 13:51

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