scholarly journals Conversion of sugar beet residues into lipids by Lipomyces starkeyi for biodiesel production

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

Abstract BackgroundLipids 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.ResultsIn 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. ConclusionsThis 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.

2020 ◽  
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.


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


2019 ◽  
Author(s):  
Francesca Martani ◽  
Letizia Maestroni ◽  
Mattia Torchio ◽  
Diletta Ami ◽  
Antonino Natalello ◽  
...  

Abstract Background: Lipids from oleaginous yeasts emerged as sustainable alternative to vegetable oils and animal fat to produce biodiesel, the biodegradable and environmentally friendly counterpart of diesel fuel. To develop economically viable microbial processes, the use of residual feedstocks as growth 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. Initially, we observed that in hydrolyzed 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). Secondly, 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 sulfate to fulfill yeasts nitrogen requirement in molasses-based media for microbial oil production. Conclusions: This study demonstrated 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 cultivation mode in bioreactor.


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.


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 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.


Author(s):  
Jiali Gui ◽  
Shuangshuang Chen ◽  
Guiying Luo ◽  
Zixiang Wu ◽  
Yongxian Fan ◽  
...  

The lipid production potential of 8 microalgae species was investigated. Among these eight species, the best strain was a dominant bloom-causing dinoflagellate, Prorocentrum donghaiense ; this species had a lipid content of 49.32±1.99% and exhibited a lipid productivity of 95.47±0.99 mg L −1 d −1 , which was 2-fold higher than the corresponding values obtained for the oleaginous microalgae Nannochloropsis gaditana and Phaeodactylum tricornutum . P. donghaiense, which is enriched in C16:0 and C22:6, is appropriate for commercial DHA production. Nitrogen or phosphorus stress markedly induced lipid accumulation to levels surpassing 75% of the dry weight, increased the C18:0 and C17:1 contents, and decreased the C18:5 and C22:6 contents, and these effects resulted in decreases in the unsaturated fatty-acid levels and changes in the lipid properties of P. donghaiense such that the species met the biodiesel specification standards. Compared with the results obtained under N-deficient conditions, the enhancement in the activity of alkaline phosphatase of P. donghaiense observed under P-deficient conditions could partly alleviate the adverse effects on the photosynthetic system exerted by P deficiency to induce the production of more carbohydrates for lipogenesis. The supernatant of the algicidal bacterium Paracoccus sp. Y42 culture lysed P. donghaiense without decreasing its lipid content, which resulted in facilitation of the downstream oil extraction process and energy savings through the lysis of algal cells. The Y42 supernatant treatment improved the lipid profiles of algal cells by increasing their C16:0, C18:0 and C18:1 contents and decreasing their C18:5 and C22:6 contents, which is favourable for biodiesel production. IMPORTANCE This study demonstrates the high potential of P. donghaiense , a dominant bloom-causing dinoflagellate, for lipid production. Compared with previously studied oleaginous microalgae, P. donghaiense exhibit greater potential for practical application due to its higher biomass and lipid contents. Nutrient deficiency and the algicidal bacterium Paracoccus sp. Y42 could improve the suitability of the lipid profile of P. donghaiense for biodiesel production. Furthermore, Paracoccus sp. Y42 effectively lyse algal cells, which facilitates the downstream oil extraction process for biodiesel production and results in energy savings through the lysing of algal cells. This study provides a more promising candidate for the production of DHA for human nutritional products and of microalgal biofuel, as well as a more cost-effective method for breaking algal cells. The high lipid productivity of P. donghaiense and algal cell lysis by algicidal bacteria contribute to reductions in the production cost of microalgal oil.


2021 ◽  
Vol 22 (3) ◽  
pp. 1304
Author(s):  
Hang Su ◽  
Jia Feng ◽  
Junping Lv ◽  
Qi Liu ◽  
Fangru Nan ◽  
...  

The oleaginous microalgae species Chlorococcum sphacosum GD is a promising feedstock for biodiesel production from soil. However, its metabolic mechanism of lipid production remains unclear. In this study, the lipid accumulation and metabolism mechanisms of Chlorococcum sphacosum GD were analyzed under salt stress based on transcriptome sequencing. The biomass and lipid content of the alga strain were determined under different NaCl concentrations, and total RNA from fresh cells were isolated and sequenced by HiSeq 2000 high throughput sequencing technology. As the salt concentration increased in culture medium, the algal lipid content increased but the biomass decreased. Following transcriptome sequencing by assembly and splicing, 24,128 unigenes were annotated, with read lengths mostly distributed in the 200–300 bp interval. Statistically significant differentially expressed unigenes were observed in different experimental groups, with 2051 up-regulated genes and 1835 down-regulated genes. The lipid metabolism pathway analysis showed that, under salt stress, gene-related fatty acid biosynthesis (ACCase, KASII, KAR, HAD, FATA) was significantly up-regulated, but some gene-related fatty acid degradation was significantly down-regulated. The comprehensive results showed that salt concentration can affect the lipid accumulation and metabolism of C. sphacosum GD, and the lipid accumulation is closely related to the fatty acid synthesis pathway.


2019 ◽  
Vol 35 (4) ◽  
pp. 1377-1383
Author(s):  
Y.C. Wong ◽  
R. Shahirah

Currently, the renewable feedstock is the most needed worldwide. Microalgae are promising raw materials for supplying biofuels due to the depletion of fossil fuels. The microalgae found were mostly consists of freshwater algae. The aim of this research is to study the effect of different solvents and ratio using Soxhlet extraction method. Many parameters were introduced in this study in order to enhance the lipid production of microalgae. Lipid content of algae oil production known as Fatty acid that found was being analyzed. Different solvents used and ratio was expected to have different highest in lipid content. Chloroform, ethanol, and hexane were chosen as the solvents used. The best solvent for lipid production was the combination of different solvents and ratio. Data showed that 8% is the highest total oil extraction yield obtained from combination of chloroform and ethanol with a ratio (1:2). The compound and lipid content in algae oil are analyzed through Gas Chromatography Mass Spectrometer (GC-MS) analysis. Fatty acids have many benefits and also have interest preparation for health products. Green microalgae strain was being identified and cultured as future potential for biodiesel production. Significant of this study is to unveil the benefit of algae oil as sustainable future resources.


Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5769
Author(s):  
Behnam Tabatabai ◽  
Afua Adusei ◽  
Alok Kumar Shrivastava ◽  
Prashant Kumar Singh ◽  
Viji Sitther

Metabolic products such as lipids and proteins produced in cyanobacteria represent an excellent source of biomass and do not compete with agricultural land use unlike soybean and corn. Given their potential use as novel materials for biodiesel production, we aimed to explore the effect of cultivation period and nitrogen concentration on the growth rate and lipid content of Fremyella diplosiphon, a model cyanobacterium. In this study, F. diplosiphon grown in BG11/HEPES medium supplemented with 1.5 g L−1 sodium nitrate (NaNO3) for 7, 10, 15, and 20 days were compared to the untreated control in media amended with 0.25, 0.5, and 1.0 g L−1 NaNO3. Cultures were inoculated in liquid media and grown under continuous fluorescent light in an orbital incubator shaker, and extracted lipids subjected to gravimetric analysis and gas chromatography-mass spectroscopy to determine the best culture conditions for lipid production. Our results demonstrated that a reduction in nitrogen concentration had no significant effect on the growth rate across all cultivation periods; however, the accumulation of total lipid content was significantly influenced by nitrogen concentration. A maximum lipid production (40%) with no reduction in growth was observed in 10-day old cultures in a BG11/HEPES medium supplemented with 1.0 g L−1 NaNO3. Fatty acid methyl ester composition of transesterified lipids demonstrated high amounts of methyl palmitate (50–70%) followed by methyl octadecenoate (17–30%) in the accumulated lipids at all treatments. Trace quantities of methyl dodecanoate, methyl hexadecanoate, methyl octadecanoate, and methyl octadecadienoate (1–8%) were also observed in all tested samples, indicating that nitrogen deprivation in culture media increases lipid production without affecting growth.


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