scholarly journals Exogenous l-proline improved Rhodosporidium toruloides lipid production on crude glycerol

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.

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.


2021 ◽  
Author(s):  
Derya Berikten ◽  
Emir Zafer Hosgun ◽  
Ayşe Gökdal Otuzbiroğlu ◽  
Berrin Bozan ◽  
Merih Kıvanç

Abstract Biodiesel is a renewable alternative fuel and glycerol as a main byproduct of the manufacturing process. Lipids could be produced from crude glycerol by using yeasts. The ability of 107 yeast strains to utilize glycerol was screened and 92 of these were selected. 60 strains were determined as a potential for lipid production by Sudan Black B staining. After secondary screening 25 of them showed specific growth rates (OD 600), high biomass production and lipid content. These strains were identified as Pichia cactophila, P. fermentans, P. anomala, Rhodotorula mucilaginosa, R. dairenensis, Clavispora lusitaniae, Saccharomyces cerevisiae, Wickerhamomyces anomalus, Candida glabrata, C. inconspicua, C. albicans, Yarrowia lipolytica with molecular identifications based on ITS and D1/D2 26S rDNA sequences. The results showed that P. cactophila accumulated lipid up to 64.94%, the highest lipid content. C16:0, C18:0, C18:1 and C18:2 essential fatty acids for biodiesel production were detected by GC-MS in the lipids accumulated by all strains. P. cactophila and C. lusitaniae were reported for the first time as lipid-producing yeasts. The results suggest that selected 25 isolates have the ability to grow on crude glycerol and especially P. cactophila produce lipid that has potential use as a feedstock for second generation biodiesel production.


2020 ◽  
Author(s):  
Tamene Milkessa Jiru

Abstract Background: Microorganisms including yeasts that are capable of accumulating lipids above 20 to 70% of their dry biomass are collectively named oleaginous. The oil produced from such microorganisms can be used as alternative sources of oils for human consumption, feedstocks for production of biodiesel, components in paints, coatings, detergents, cleaning products, cosmetics, plastics, rubber and intermediate products.Results: In this study Cutaneotrichosporon curvatus (Cryptococcus curvatus) PY39, an oleaginous yeast, isolated from flower surface in Ethiopia, was grown under nitrogen-limited media. The capacity of this strain with respect to biomass production, lipid yield and lipid content was evaluated. To determine the optimal culture conditions for this oleaginous yeast, different carbon and nitrogen sources, carbon to nitrogen (C/N) ratio, pH, incubation temperature, shaking speed and incubation period were investigated. The optimal fermentation conditions were obtained as follows: 70 g/L of glucose as carbon source; combinations of ammonium sulphate and yeast extract as nitrogen sources at, respectively, 0.50 g/L and 0.47 g/L; initial pH of 5.0; temperature at 30oC, shaking speed of 225 rpm, and cultivated for 144 h. Under the optimized conditions, C.curvatus PY39 accumulated lipids up to 7.22±0.26 g/L on dry biomass basis. Such values correspond to lipid content of 48.66±0.60%. This strain was further grown on media containing peel mixtures of papaya and mango. Under the optimized conditions, C. curvatus PY39 exhibited a lipid yield and lipid content of 3.95±0.67 g/L and 35.02±1.63%, respectively. The fatty acid profiles were analyzed using gas chromatography. Data revealed the presence of significant amount of oleic acid (54.40±1.15%), palmitic acid (17.39±0.47%), stearic acid (13.16±0.93%) and low amount of other fatty acids in the extracted yeast oils which indicate that the fatty acid profiles were very similar to that of conventional vegetable oils.Conclusion: The results of fatty acid profiles showed that the microbial lipids from the studied yeast can be good feedstocks for biodiesel production.


2017 ◽  
Vol 5 (2) ◽  
pp. 88
Author(s):  
Bruno Loureiro Ladeira ◽  
Janaína Fernandes de Medeiros Burkert ◽  
Carlos André Burkert

Biodiesel production, which has been increasing worldwide, transformed crude glycerol, the main byproduct of the reaction, into a commodity of low commercial value, especially due to the high costs involved in its purification process and to the fact that the market cannot account for its generation. Therefore, this study aims at contributing to the search for technological alternatives to the use of surplus crude glycerol so as to add value to this byproduct by using it as the carbon source for the yeast Meyerozyma guilliermondii, in order to yield lipids. The Central Composite Rotational Design was proposed to establish empirical models, codified for lipid content, production and productivity as the result of concentrations of Magnesium Sulfate Heptahydrate (MgSO4.7H2O) and yeast extract. In the optimized conditions, the lipid content in dry basis, lipid production and lipid productivity were 8.25%, 1.10 g.L-1 and 0.0092 g.L-1.h-1, respectively obtained.


2021 ◽  
Vol 10 (1) ◽  
pp. 41-45
Author(s):  
Slavica Ilić ◽  
Jovan Ćirić ◽  
Gordana Gojgić-Cvijović

In this paper we studied the effect of different amino acids (arginine, tryptophan, tyrosine, and phenylalanine) as nitrogen sources on the growth of actinomycete Streptomyces hygroscopicus CH-7 and the consumption of crude glycerol, obtained as a by-product in the biodiesel production from sunflower oil. The highest biomass concentration (9.5 g/L) was achieved using the basic medium and the medium with tryptophan (9.2 g/L), while the crude glycerol consumption was the highest in the basic medium (5.9 mg/mL) and the medium with phenylalanine (3.3 mg/mL).


2021 ◽  
Vol 16 (10) ◽  
pp. 144-155
Author(s):  
Van Lal Michael Chhandama ◽  
Belur Kumudini Satyan

Microalgae emerged as a competent feedstock for biodiesel production because of high growth rate and lipid content. This work focuses on isolation of novel microalgal strain from different sources of water for the production of biodiesel. The isolated microalgae, Pleurastrum insigne possessed high lipid content (~28 % dcw), further optimized to 57.06 % dcw using a statistical design (CCD) under Response Surface Methodology. Lipid production was optimized by nutrient (nitrogen and phosphorus) and pH stress. The different type of fatty acids present in the optimized lipid was also profiled using GCMS. Biodiesel yield was found to be 82.14 % of the total lipid and the fuel properties tested have met IS, ASTM and EN biodiesel standards.


2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Francesca Martani ◽  
Letizia Maestroni ◽  
Mattia Torchio ◽  
Diletta Ami ◽  
Antonino Natalello ◽  
...  

Abstract Background Lipids from oleaginous yeasts emerged as a sustainable alternative to vegetable oils and animal fat to produce biodiesel, the biodegradable and environmentally friendly counterpart of petro-diesel fuel. To develop economically viable microbial processes, the use of residual feedstocks as growth and production substrates is required. Results In this work we investigated sugar beet pulp (SBP) and molasses, the main residues of sugar beet processing, as sustainable substrates for the growth and lipid accumulation by the oleaginous yeast Lipomyces starkeyi. We observed that in hydrolysed SBP the yeast cultures reached a limited biomass, cellular lipid content, lipid production and yield (2.5 g/L, 19.2%, 0.5 g/L and 0.08 g/g, respectively). To increase the initial sugar availability, cells were grown in SBP blended with molasses. Under batch cultivation, the cellular lipid content was more than doubled (47.2%) in the presence of 6% molasses. Under pulsed-feeding cultivation, final biomass, cellular lipid content, lipid production and lipid yield were further improved, reaching respectively 20.5 g/L, 49.2%, 9.7 g/L and 0.178 g/g. Finally, we observed that SBP can be used instead of ammonium sulphate to fulfil yeasts nitrogen requirement in molasses-based media for microbial oil production. Conclusions This study demonstrates for the first time that SBP and molasses can be blended to create a feedstock for the sustainable production of lipids by L. starkeyi. The data obtained pave the way to further improve lipid production by designing a fed-batch process in bioreactor. Graphical abstract


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