Secretory expression of β-1,3-glucomannanase in the oleaginous yeast Rhodosporidium toruloides for improved lipid extraction

• Published in: Bioresources and bioprocessing Vol. 10; no. 1; p. 16
• Main Authors: Liang, Shiyu, Zhang, Yue, Lyu, Liting, Wang, Shuang, Zhao, Zongbao K.
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 02.03.2023; Springer Nature B.V; SpringerOpen
• Subjects: Acetic acid; Biochemical Engineering; Biofuels; Biomanufacturing Driven by Synthetic Biology; Cell culture; Cell growth; Cell wall engineering; Cell walls; Chemistry; Chemistry and Materials Science; Dry cells; Environmental Engineering/Biotechnology; Ethyl acetate; Genomes; Heat treatment; Industrial and Production Engineering; Lipid extraction; Lipids; Oleaginous yeast; Rhodosporidium toruloides; Secretory expression; Yeast; β-1,3-glucomannanase; Lipid extraction; Cell wall engineering; Oleaginous yeast; β-1,3-glucomannanase; Secretory expression; Rhodosporidium toruloides
• ISSN: 2197-4365; 2197-4365
• DOI: 10.1186/s40643-023-00639-2

Lipids produced by oleaginous yeasts are considered as sustainable sources for the production of biofuels and oleochemicals. The red yeast Rhodosporidium toruloides can accumulate lipids to over 70% of its dry cell mass. To facilitate lipid extraction, a recombinant β-1,3-glucomannanase, MAN5C, has been applied to partially breakdown R. toruloides cell wall. In this study, R. toruloides NP11 was engineered for secretory expression of MAN5C to simplify the lipid extraction process. Specifically, a cassette contained a codon-optimized gene MAN5C was integrated into the genome of R. toruloides by Agrobacterium -mediated transformation. The engineered strain NP11-MAN5C was found with proper expression and secretion of active MAN5C, yet no notable compromise in terms of cell growth and lipid production. When NP11-MAN5C cell cultures were extracted with ethyl acetate without any pretreatment, 20% of total lipids were recovered, 4.3-fold higher than that of the parental strain NP11. When the cells were heat-treated followed by extraction with ethyl acetate in the presence of the culture broth supernatants, up to 93% of total lipids were recovered, confirming beneficial effects of MAN5C produced in situ. This study provides a new strategy to engineer oleaginous yeasts for more viable lipid extraction and down-stream processes. Graphical Abstract