scholarly journals Strategies for Improvement of Lipid Production by Yeast Trichosporon oleaginosus from Lignocellulosic Biomass

2021 ◽  
Vol 7 (11) ◽  
pp. 934
Author(s):  
Marina Grubišić ◽  
Katarina Mihajlovski ◽  
Ana Marija Gruičić ◽  
Sunčica Beluhan ◽  
Božidar Santek ◽  
...  

Microbial lipids have similar fatty acid composition to plant oils, and therefore, are considered as an alternative feedstock for biodiesel production. Oleaginous yeasts accumulate considerable amounts of lipids intracellularly during growth on low-cost renewable feedstocks such as lignocellulosic biomass. In this study, we cultivated yeast Trichosporon oleaginosus on hydrolysate of alkaline pretreated corn cobs. Different process configurations were evaluated and compared, including separate hydrolysis and fermentation (SHF) with cellulase recycle and simultaneous saccharification and fermentation (SSF) in batch and fed-batch mode. At low enzyme loading, the highest lipid concentration of 26.74 g L−1 was reached in fed-batch SSF fed with 2.5% (g g−1) substrate. Batch SHF was conducted for four rounds with recycling the cellulase adsorbed on unhydrolyzed lignocellulosic biomass. Thirty percent of cellulase saving was achieved for rounds 2–4 without compromising productivity and lipid yield. The addition of Tween 80 to lignocellulosic slurry improved the hydrolysis rate of structural carbohydrates in pretreated lignocellulosic biomass. Furthermore, supplementing the growth medium with Tween 80 improved lipid yield and productivity without affecting yeast growth. Oleaginous yeast T. oleaginosus is a promising strain for the sustainable and efficient production of lipids from renewable lignocellulosic feedstock.

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1473
Author(s):  
Marco Castellini ◽  
Stefano Ubertini ◽  
Diego Barletta ◽  
Ilaria Baffo ◽  
Pietro Buzzini ◽  
...  

Today one of the most interesting ways to produce biodiesel is based on the use of oleaginous microorganisms, which can accumulate microbial oil with a composition similar to vegetable oils. In this paper, we present a thermo-chemical numerical model of the yeast biodiesel production process, considering cardoon stalks as raw material. The simulation is performed subdividing the process into the following sections: steam explosion pre-treatment, enzymatic hydrolysis, lipid production, lipid extraction, and alkali-catalyzed transesterification. Numerical results show that 406.4 t of biodiesel can be produced starting from 10,000 t of lignocellulosic biomass. An economic analysis indicates a biodiesel production cost of 12.8 USD/kg, thus suggesting the need to increase the capacity plant and the lipid yield to make the project economically attractive. In this regard, a sensitivity analysis is also performed considering an ideal lipid yield of 22% and 100,000 t of lignocellulosic biomass. The biodiesel production costs related to these new scenarios are 7.88 and 5.91 USD/kg, respectively. The large capacity plant combined with a great lipid yield in the fermentation stage shows a biodiesel production cost of 3.63 USD/kg making the product competitive on the current market of biofuels by microbial oil.


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.


2018 ◽  
Vol 7 (4) ◽  
pp. 323-333
Author(s):  
Afshin Abrishamkar ◽  
Armin Franz Isenmann ◽  
Amin Abrishamkar

Abstract Glycerin (glycerol) is a co-product of biodiesel production that is widely produced and is available at a low cost. To date, various applications have been investigated and introduced for biodiesel glycerin. In this study, a number of valuable products were produced using biodiesel glycerin and formic acid as the main reactants. Allyl alcohol is one of the valuable chemicals produced from glycerin monoformate. Efficient production of this product requires successful completion of the first section of the reaction, which is an equilibrium reaction. The highest feasible yield achieved was about 83% (based on the consumption of formic acid) at 120–140°C without the addition of any catalysts. Also, the esterification reaction was further investigated at room temperature, where the equilibrium state was reached with a yield of 55% after only 4 h. Moreover, the addition of urea to the reaction with the aim of producing the other two side products, i.e. diformyl urea and glycerin carbonate, in addition to glycerin monoformate, was studied. The results showed that considerable amounts of applicable byproducts, e.g. formamid, are also produced, making the process even more economical.


Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1228 ◽  
Author(s):  
Zhi-Peng Wang ◽  
Qin-Qing Wang ◽  
Song Liu ◽  
Xiao-Fang Liu ◽  
Xin-Jun Yu ◽  
...  

: Cane molasses is one of the main by-products of sugar refineries, which is rich in sucrose. In this work, low-cost cane molasses was introduced as an alternative substrate for isomaltulose production. Using the engineered Yarrowia lipolytica, the isomaltulose production reached the highest (102.6 g L−1) at flask level with pretreated cane molasses of 350 g L−1 and corn steep liquor of 1.0 g L−1. During fed-batch fermentation, the maximal isomaltulose concentration (161.2 g L−1) was achieved with 0.96 g g−1 yield within 80 h. Simultaneously, monosaccharides were completely depleted, harvesting the high isomaltulose purity (97.4%) and high lipid level (12.2 g L−1). Additionally, the lipids comprised of 94.29% C16 and C18 fatty acids, were proved suitable for biodiesel production. Therefore, the bioprocess employed using cane molasses in this study was low-cost and eco-friendly for high-purity isomaltulose production, coupling with valuable lipids.


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.


Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 315
Author(s):  
Domenico Aiello ◽  
Ciro Sannino ◽  
Tommaso Giannoni ◽  
Giacomo Fabbrizi ◽  
Mattia Gelosia ◽  
...  

The lipogenic ability of the yeast Solicoccozyma terricola DBVPG 5870 grown on hydrolyzed lignocellulose obtained from cardoon stalks was evaluated. Data on cell biomass, lipid production, and fatty acid profiles of triacylglycerols obtained in batch and fed-batch experiments were carried out at the laboratory scale in a 5L fermenter, and at two different temperatures (20 and 25 °C) were reported. The higher production of total intracellular lipids (13.81 g/L) was found in the fed-batch experiments carried out at 20 °C. S. terricola exhibited the ability to produce high amounts of triacylglycerol (TAGs) with a characteristic fatty acids profile close to that of palm oil. The TAGs obtained from S. terricola grown on pre-treated lignocellulose could be proposed as a supplementary source of oleochemicals. Indeed, due to the rising prices of fossil fuels and because of the environmental-related issues linked to their employment, the use of TAGs produced by S. terricola grown on lignocellulose could represent a promising option as a supplementary oleochemical, especially for biodiesel production.


Author(s):  
Weizhu Zeng ◽  
Junyi Wang ◽  
Xiaoyu Shan ◽  
Shiqin Yu ◽  
Jingwen Zhou

Scleroglucan is a non-ionic water-soluble polysaccharide, and has been widely used in the petroleum, food, medicine and cosmetics industries. Currently, scleroglucan is mainly produced by Sclerotium rolfsii. A higher level of scleroglucan (42.0 g/L) was previously obtained with S. rolfsii WSH-G01. However, the production of scleroglucan was reduced despite a higher glucose concentration remaining. Additionally, the molecular weight of scleroglucan was large, thus restricted its application. In this study, by adjusting the state of seeds inoculated, the degradation issue of scleroglucan during the fermentation process was solved. By comparing different fed-batch strategies, 66.6 g/L of scleroglucan was harvested by a two-dose fed-batch mode, with 53.3% glucose conversion ratio. To modify the molecular weight of scleroglucan, a combination method with HCl and high-pressure homogenization treatment was established. Finally, scleroglucan with molecular weight of 4.61 × 105 Da was obtained. The developed approaches provide references for the biosynthesis and molecular weight modification of polysaccharides.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Meishan Fan ◽  
Jun Li ◽  
Guican Bi ◽  
Guangying Ye ◽  
Hongdan Zhang ◽  
...  

Abstract Background The mixed-feedstock fermentation is a promising approach to enhancing the co-generation of cellulosic ethanol and methane from sugarcane bagasse (SCB) and molasses. However, the unmatched supply of the SCB and molasses remains a main obstacle built upon binary feedstock. Here, we propose a cellulose–starch–sugar ternary waste combinatory approach to overcome this bottleneck by integrating the starch-rich waste of Dioscorea composita Hemls. extracted residue (DER) in mixed fermentation. Results The substrates of the pretreated SCB, DER and molasses with varying ratios were conducted at a relatively low solids loading of 12%, and the optimal mixture ratio of 1:0.5:0.5 for the pretreated SCB/DER/molasses was determined by evaluating the ethanol concentration and yield. Nevertheless, it was found that the ethanol yield decreased from 79.19 ± 0.20 to 62.31 ± 0.61% when the solids loading increased from 12 to 44% in batch modes, regardless of the fact that the co-fermentation of three-component feedstock was performed under the optimal condition defined above. Hence, different fermentation processes such as fed-batch and fed-batch + Tween 80 were implemented to further improve the ethanol concentration and yield at higher solids loading ranging between 36 and 44%. The highest ethanol concentration of 91.82 ± 0.86 g/L (69.33 ± 0.46% of theoretical yield) was obtained with fed-batch + Tween 80 mode during the simultaneous saccharification and fermentation at a high solids loading of 44%. Moreover, after the ethanol recovery, the remaining stillage was digested for biomethane production and finally yielded 320.72 ± 6.98 mL/g of volatile solids. Conclusions Integrated DER into the combination of SCB and molasses would be beneficial for ethanol production. The co-generation of bioethanol and biomethane by mixed cellulose–starch–sugar waste turns out to be a sustainable solution to improve the overall efficacy in biorefinery.


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