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Doctoral thesis2023Open access

Insights into genomics and gene expression of oleaginous yeasts of the genus Rhodoturula

Martín Hernández, Giselle De La Caridad

Abstract

The Rhodotorula glutinis cluster includes oleaginous yeast species with high biotechnological potential as cell factories for lipid, carotenoid, and oleochemical production. They can grow on various low-cost residues, such as lignocellulose and crude glycerol. The accumulated microbial lipids have a fatty acid composition similar to vegetable oils, representing a sustainable alternative in food, feed, and biofuel industries. Strain manipulation could further increase its economic attractiveness. A basic prerequisite for this is to understand the genome organization of Rhodotorula spp. and the lipid and carotenoid metabolism on residual products in detail. This doctoral thesis made a substantial contribution to this:

Hybrid genome assemblies from R. toruloides, R. glutinis, and R. babjevae were built de novo using a combination of short- and long-read sequencing. By doing this, high-quality genomes could be achieved, showing high completeness and contiguity (near-chromosome level). Among other things, this enabled the prediction of ploidy and the discovery of extrachromosomal structures. Phylogenetic analyses revealed high intraspecific divergence in R. babjevae. Using RNA-seq data generated from different growth conditions, gene annotation for R. toruloides could be significantly increased, and comprehensive gene expression data could be obtained. These allowed conclusions to be drawn about the activation and mechanism of lipid accumulation in R. toruloides grown on residual products such as crude glycerol and hemicellulosic hydrolysate.

Keywords

Microbial lipids; Genomics; de novo hybrid assembly; Annotation; Genome divergence; Ploidy; Transcriptomics; Lignocellulose; Glycerol

Published in

Acta Universitatis Agriculturae Sueciae
2023, number: 2023:46ISBN: 978-91-8046-144-3, eISBN: 978-91-8046-145-0Publisher: Swedish University of Agricultural Sciences

    UKÄ Subject classification

    Microbiology
    Biochemistry and Molecular Biology

    Publication identifier

    DOI: https://doi.org/10.54612/a.39o6ovnn6m

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/121943