Partial purification and properties of pyruvate kinase and its regulatory role during lipid accumulation by the oleaginous yeast Rhodosporidium toruloides CBS 14

1985 ◽  
Vol 31 (5) ◽  
pp. 479-484 ◽  
Author(s):  
Christopher Thomas Evans ◽  
Colin Ratledge

Pyruvate kinase from the oleaginous yeast Rhodosporidium toruloides CBS 14 was partially purified and its properties investigated to determine its role during lipid production by this yeast. The enzyme (relative mass (Mr) = 190 000) showed a pH optimum of 8.0 and apparent Km values for K+, phosphoenolpyruvate (PEP), and ADP of 1.6 mM, 571 μM, and 120 μM, respectively. Enzyme activity was inhibited by citrate, isocitrate, ATP, GTP, and CTP and activated by fructose 1,6-bisphosphate, L-glutamate, and [Formula: see text] ions. Inhibition by citrate and ATP were both competitive with PEP with the Ki(citrate) = 340 μM and Ki(ATP) = 303 μM. The effect of ATP and cellular energy charge were critically dependent on the concentration of ADP present in the enzyme assay. Both L-glutamate and fructose 1,6-bisphosphate increased the affinity of the enzyme for both PEP and ADP and so were significant activators at nonsaturating substrate concentrations. [Formula: see text] ions increased the affinity of the enzyme for PEP, but not ADP. The modulation of pyruvate kinase activity by such a wide range of effectors is indicative of a major regulatory role in controlling the flux of carbon, through glycolysis, into lipid-synthesizing systems.

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Sujit Sadashiv Jagtap ◽  
Ashwini Ashok Bedekar ◽  
Jing-Jing Liu ◽  
Yong-Su Jin ◽  
Christopher V. Rao

Abstract Background Sugar alcohols are commonly used as low-calorie sweeteners and can serve as potential building blocks for bio-based chemicals. Previous work has shown that the oleaginous yeast Rhodosporidium toruloides IFO0880 can natively produce arabitol from xylose at relatively high titers, suggesting that it may be a useful host for sugar alcohol production. In this work, we explored whether R. toruloides can produce additional sugar alcohols. Results Rhodosporidium toruloides is able to produce galactitol from galactose. During growth in nitrogen-rich medium, R. toruloides produced 3.2 ± 0.6 g/L, and 8.4 ± 0.8 g/L galactitol from 20 to 40 g/L galactose, respectively. In addition, R. toruloides was able to produce galactitol from galactose at reduced titers during growth in nitrogen-poor medium, which also induces lipid production. These results suggest that R. toruloides can potentially be used for the co-production of lipids and galactitol from galactose. We further characterized the mechanism for galactitol production, including identifying and biochemically characterizing the critical aldose reductase. Intracellular metabolite analysis was also performed to further understand galactose metabolism. Conclusions Rhodosporidium toruloides has traditionally been used for the production of lipids and lipid-based chemicals. Our work demonstrates that R. toruloides can also produce galactitol, which can be used to produce polymers with applications in medicine and as a precursor for anti-cancer drugs. Collectively, our results further establish that R. toruloides can produce multiple value-added chemicals from a wide range of sugars.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Rasool Kamal ◽  
Yuxue Liu ◽  
Qiang Li ◽  
Qitian Huang ◽  
Qian Wang ◽  
...  

Abstract Background Crude glycerol as a promising feedstock for microbial lipid production contains several impurities that make it toxic stress inducer at high amount. Under stress conditions, microorganisms can accumulate l-proline as a safeguard. Herein, l-proline was assessed as an anti-stress agent in crude glycerol media. Results Crude glycerol was converted to microbial lipids by the oleaginous yeast Rhodosporidium toruloides CGMCC 2.1389 in a two-staged culture mode. The media was supplied with exogenous l-proline to improve lipid production efficiency in high crude glycerol stress. An optimal amount of 0.5 g/L l-proline increased lipid titer and lipid yield by 34% and 28%, respectively. The lipid titer of 12.2 g/L and lipid content of 64.5% with a highest lipid yield of 0.26 g/g were achieved with l-proline addition, which were far higher than those of the control, i.e., lipid titer of 9.1 g/L, lipid content of 58% and lipid yield of 0.21 g/g. Similarly, l-proline also improved cell growth and glycerol consumption. Moreover, fatty acid compositional profiles of the lipid products was found suitable as a potential feedstock for biodiesel production. Conclusion Our study suggested that exogenous l-proline improved cell growth and lipid production on crude glycerol by R. toruloides. The fact that higher lipid yield as well as glycerol consumption indicated that l-proline might act as a potential anti-stress agent for the oleaginous yeast strain.


2019 ◽  
Vol 294 ◽  
pp. 122122 ◽  
Author(s):  
Philipp Arbter ◽  
Aakanksha Sinha ◽  
Julie Troesch ◽  
Tyll Utesch ◽  
An-Ping Zeng

2013 ◽  
Vol 130 ◽  
pp. 339-344 ◽  
Author(s):  
Qitian Huang ◽  
Qian Wang ◽  
Zhiwei Gong ◽  
Guojie Jin ◽  
Hongwei Shen ◽  
...  

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1053 ◽  
Author(s):  
Xiaozan Dai ◽  
Hongwei Shen ◽  
Qiang Li ◽  
Kamal Rasool ◽  
Qian Wang ◽  
...  

Dry acid pretreatment and biodetoxification (DryPB) has been considered as an advanced technology to treat lignocellulosic materials for improved downstream bioconversion. In this study, the lipid production from DryPB corn stover was investigated by the oleaginous yeast Rhodosporidium toruloides using a new process designated prehydrolysis followed by simultaneous saccharification and lipid production (PreSSLP). The results found that prehydrolysis at 50 °C and then lipid production at 30 °C improved lipid yield by more than 17.0% compared with those without a prehydrolysis step. The highest lipid yield of 0.080 g/g DryPB corn stover was achieved at a solid loading of 12.5%. The fatty acid distribution of lipid products was similar to those of conventional vegetable oils that are used for biodiesel production. Our results suggested that the integration of DryPB process and PreSSLP process can be explored as an improved technology for microbial lipid production from lignocellulosic materials.


Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1576 ◽  
Author(s):  
Qiang Li ◽  
Rasool Kamal ◽  
Qian Wang ◽  
Xue Yu ◽  
Zongbao Kent Zhao

Microbial lipids have been considered as promising resources for the production of renewable biofuels and oleochemicals. Various feedstocks, including sugars, crude glycerol, and volatile fatty acids, have been used as substrates for microbial lipid production, yet amino acid (AA) wastes remain to be evaluated. Here, we describe the potential to use AA wastes for lipid production with a two-stage culture mode by an oleaginous yeast strain Rhodosporidium toruloides CGMCC 2.1389. Each of the 20 proteinogenic AAs was evaluated individually as sole carbon source, with 8 showing capability to facilitate cellular lipid contents of more than 20%. It was found that L-proline was the most favored AA, with which cells accumulated lipids to a cellular lipid content of 37.3%. When blends with AA profiles corresponding to those of meat industry by-products and sheep viscera were used, the cellular lipid contents reached 27.0% and 28.7%, respectively. The fatty acid compositional analysis of these lipid products revealed similar profiles to those of vegetable oils. These results, thus, demonstrate a potential route to convert AA wastes into lipids, which is of great importance for waste management and biofuel production.


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