Isolation of a thermotolerant Rhodosporidium toruloides DMKU3-TK16 mutant and its fatty acid profile at high temperature

Abstract

Oleaginous yeast Rhodosporidium toruloides DMKU3-TK16 (TK16), which was isolated from Thailand, is considered a promising lipid producer for biodiesel production. For future industrial applications of this strain, thermotolerant traits are highly desired for their potential to reduce cooling costs in a commercial fermenter. Here, by using an adaptive breeding strategy, we isolated a thermotolerant R. toruloides mutant, L1-1. The isolated L1-1 strain exhibited better growth and higher lipid production at 37°C, and it was found to have significantly higher oleic acid (C18:1) content and yield compared with the wild-type TK16 when cultivated at 37°C. This is the first study to isolate a thermotolerant strain from the oleaginous yeast R. toruloides. The information gained herein will provide new clues for engineering lipid production and for studying the thermotolerance of R. toruloides.

Blastobotrys adeninivorans and B. raffinosifermentans, two sibling yeast species which accumulate lipids at elevated temperatures and from diverse sugars

“…The FA profile at 45 °C was highly similar to that at 42 °C for each strain. The strategy of adaptation to ‘high’ temperatures expectedly varies among species and strains; in the aforementioned R. toruloides thermotolerant mutant, a temperature increase from 30 to 37 °C, while stimulating lipid production, drastically raised the relative proportion of C18:1, which reached 86% of total FA [32].…”

“…None of these species has been reported to grow at temperatures above 37 °C, though some thermotolerant strains may have been isolated. An R. toruloides DMKU3-TK16 mutant obtained through an adaptive breeding strategy can store lipids at approximately 14% DCW at 37 °C [32]. However, working at upper temperatures could provide specific advantages for compound solubilization (e.g., FA), help to minimize the costs of cooling of bioreactors and facilitate consolidated bioprocesses.…”

Exploring Yeast Diversity to Produce Lipid-Based Biofuels from Agro-Forestry and Industrial Organic Residues

“…The most promising result was obtained for the aldehyde dehydrogenase FALDH2 , leading to the highest conversion rate of furfural to furoic acid, as well as a two-fold increase in cell growth and lipid production in the presence of 0.4 g/L of furfural [ 266 ]. The thermotolerant L1–1 strain of R. toruloides , obtained by an adaptive breeding strategy [ 267 ], was also found to tolerate (i) oxidative stress (ethanol and hydrogen peroxide), (ii) osmotic stress (high glucose concentrations), and (iii) cell membrane disturbing reagent (DMSO) [ 268 ]. This strain, which produced high titers of lipids, was able to cope with the increase in ROS and presented a stronger cell wall and increased levels of unsaturated membrane lipids under various stresses [ 268 ].…”

Development and Perspective of Rhodotorula toruloides as an Efficient Cell Factory

“…10,11 In addition, R. toruloides utilizes a wide range of substrates for growth, including sugars (e.g., xylose 12,13 and galactose 14 ), D-galacturonic acid, 15 inulin, 16 glycerin, 17 lignocellulose hydrolysate, 18−20 as well as some industrial wastes, including vegetable waste, 21 crude glycerol (byproduct of biodiesel preparation), 22 and industrial wastewater. 17,23,24 It also shows a tolerance against high osmotic stress, 25 low pH, 18,26 high temperature, 27 and oxidative stress (e.g., ethanol and H 2 O 2 ). 28,29 Moreover, it has been demonstrated that R. toruloides can grow to high density.…”

“…Increasing interests have been focused on the Pucciniomycotina yeast Rhodotorula toruloides (also known as Rhodosporidium toruloides) due to its high cellular lipid content of over 70% under certain conditions, which is significantly more than that of wild-type Yarrowia lipolytica, the most commonly used oleaginous yeast. , In addition, R. toruloides utilizes a wide range of substrates for growth, including sugars (e.g., xylose , and galactose), d -galacturonic acid, inulin, glycerin, lignocellulose hydrolysate, − as well as some industrial wastes, including vegetable waste, crude glycerol (byproduct of biodiesel preparation), and industrial wastewater. ,, It also shows a tolerance against high osmotic stress, low pH, , high temperature, and oxidative stress (e.g., ethanol and H 2 O 2 ). , Moreover, it has been demonstrated that R. toruloides can grow to high density .…”