Rhodotorula toruloides is a non-conventional red yeast that can synthesize various carotenoids and lipids. It can utilize a variety of cost-effective raw materials, tolerate and assimilate toxic inhibitors in lignocellulosic hydrolysate. At present, it is widely investigated for the production of microbial lipids, terpenes, high-value enzymes, sugar alcohols and polyketides. Given its broad industrial application prospects, researchers have carried out multi-dimensional theoretical and technological exploration, including research on genomics, transcriptomics, proteomics and genetic operation platform. Here we review the recent progress in metabolic engineering and natural product synthesis of R. toruloides, and prospect the challenges and possible solutions in the construction of R. toruloides cell factory.
Gene Editing ; Metabolic Engineering ; Rhodotorula/metabolism* ; Lipids

Six kinds of elicitors were prepared respectively from Neurospora crassa, Monascus purpureus, Sporobolomyces roseus, Rhodotorula rubra, Nocardia sp. N89 and Actinoplanes sp. A05. When Penicillium sp. PT95 was incubated in Czapek's agar plates containing appropriate amounts of elicitors, both its sclerotia biomass and carotenoid content accumulated in sclerotia were enhanced significantly (P < 0.01). Among tested elicitors, the elicitors from the fungi N. crassa, M. purpureus, S.-roseus and R. rubra were more effective than those from the actinomycetes Nocardia sp. N89 and Actinoplanes sp. A05; the elicitor from M. purpureus gave the highest carotenoid yield of 599 micrograms/plate, 2.76 times higher than that of control. Every one of elicitors except that from M. purpureus could increase significantly the proportion of beta-carotene in total carotenoids (P < 0.01).
Actinomycetales ; physiology ; Biomass ; Carotenoids ; biosynthesis ; Neurospora crassa ; physiology ; Nocardia ; physiology ; Penicillium ; metabolism ; Rhodotorula ; physiology

In order to illustrate the effects of furfural, one of the most common inhibitory compounds in lignocellulosic hydrolysate, on oleaginous yeast Rhodotorula glutinis, we investigated the effects of different concentrations of furfural (0.1, 0.4, 0.6 and 1.5 g/L) on the biomass and lipid production of R. glutinis, as well as the effects of 1.0 g/L furfural on the utilization of glucose and xylose. Results showed that: when the furfural concentration reached 1.5 g/L, the lag phrase time was extended to 96 h, and the residual glucose was up to 17.7 g/L, with maximum biomass of only 6.6 g/L, which accounted for 47% of that in the basic medium (furfural-free), and the corresponding lipid content was reduced about 50%. Furfural showed lighter inhibitory degree on R. glutinis when xylose acted as the carbon source than glucose was the carbon source; more C18 fatty acids or unsaturated C18 fatty acids were generated in the presence of furfural.
Biomass ; Carbon ; Culture Media ; Fatty Acids ; biosynthesis ; Furaldehyde ; chemistry ; Glucose ; Industrial Microbiology ; Rhodotorula ; growth & development ; metabolism ; Xylose

Acetic acid, as a main by-product generated in the pretreatment process of lignocellulose hydrolysis, significantly affects cell growth and lipid synthesis of oleaginous microorganisms. Therefore, we studied the tolerance of Rhodotorula glutinis to acetic acid and its lipid synthesis from substrate containing acetic acid. In the mixed sugar medium containing 6 g/L glucose and 44 g/L xylose, and supplemented with acetic acid, the cell growth was not:inhibited when the acetic acid concentration was below 10 g/L. Compared with the control, the biomass, lipid concentration and lipid content of R. glutinis increased 21.5%, 171% and 122% respectively when acetic acid concentration was 10 g/L. Furthermore, R. glutinis could accumulate lipid with acetate as the sole carbon source. Lipid concentration and lipid yield reached 3.20 g/L and 13% respectively with the initial acetic acid concentration of 25 g/L. The lipid composition was analyzed by gas chromatograph. The main composition of lipid produced with acetic acid was palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, including 40.9% saturated fatty acids and 59.1% unsaturated fatty acids. The lipid composition was similar to that of plant oil, indicating that lipid from oleaginous yeast R. glutinis had potential as the feedstock of biodiesel production. These results demonstrated that a certain concentration of acetic acid need not to be removed in the detoxification process when using lignocelluloses hydrolysate to produce microbial lipid by R. glutinis.
Acetic Acid ; Biofuels ; Biomass ; Culture Media ; Fatty Acids ; Hydrolysis ; Industrial Microbiology ; Lignin ; chemistry ; Linoleic Acid ; Lipids ; biosynthesis ; Oleic Acid ; Rhodotorula ; metabolism