scholarly journals Molecular Mechanism of Lipid Accumulation and Metabolism of Oleaginous Chlorococcum sphacosum GD from Soil under Salt Stress

2021 ◽  
Vol 22 (3) ◽  
pp. 1304
Author(s):  
Hang Su ◽  
Jia Feng ◽  
Junping Lv ◽  
Qi Liu ◽  
Fangru Nan ◽  
...  
Keyword(s):  
Salt Stress ◽  
Fatty Acid ◽  
Lipid Content ◽  
Salt Concentration ◽  
Lipid Accumulation ◽  
Transcriptome Sequencing ◽  
High Throughput Sequencing ◽  
Lipid Production ◽  
Biodiesel Production ◽  
Oleaginous Microalgae

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.

scholarly journals Lipid accumulation of Chlorella sp. TLD6B from the Taklimakan Desert under salt stress

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11525
Author(s):  
Hong Li ◽  
Jun Tan ◽  
Yun Mu ◽  
Jianfeng Gao
Keyword(s):  
Salt Stress ◽  
Fatty Acid ◽  
Lipid Accumulation ◽  
Large Scale ◽  
Fatty Acid Biosynthesis ◽  
High Salinity ◽  
Raw Material ◽  
Biodiesel Production ◽  
Taklimakan Desert ◽  
Acid Biosynthesis

Chlorella has become an important raw material for biodiesel production in recent years, and Chlorella sp. TLD6B, a species with high lipid concentrations and high salt and drought tolerance, has been cultivated on a large scale. To explore the lipid accumulation of Chlorella sp. TLD6B and its relationship to external NaCl concentrations, we performed physiological measurements and genome-wide gene expression profiling under different levels of salt stress. Chlorella sp. TLD6B was able to tolerate high levels of salt stress (0.8 M NaCl addition). Lipid concentrations initially increased and then decreased as salt stress increased and were highest under the addition of 0.2 M NaCl. Comparative transcriptomic analysis revealed that salt stress enhanced the expression of genes related to sugar metabolism and fatty acid biosynthesis (the ACCases BC and BCCP, KAS II, and GPDHs involved in TAG synthesis), thereby promoting lipid accumulation under the addition of 0.2 M NaCl. However, high salinity inhibited cell growth. Expression of three SADs, whose encoded products function in unsaturated fatty acid biosynthesis, was up-regulated under high salinity (0.8 M NaCl addition). This research clarifies the relationship between salt tolerance and lipid accumulation and promotes the utilization of Chlorella sp. TLD6B.

scholarly journals Nutrient deficiency and an algicidal bacterium improved the lipid profiles of a novel promising oleaginous dinoflagellate, Prorocentrum donghaiense, for biodiesel production

2021 ◽  
Author(s):  
Jiali Gui ◽  
Shuangshuang Chen ◽  
Guiying Luo ◽  
Zixiang Wu ◽  
Yongxian Fan ◽  
...  
Keyword(s):  
Lipid Content ◽  
Energy Savings ◽  
Lipid Production ◽  
Nutrient Deficiency ◽  
Extraction Process ◽  
Oil Extraction ◽  
Biodiesel Production ◽  
Prorocentrum Donghaiense ◽  
Algicidal Bacterium ◽  
Oleaginous Microalgae

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.

scholarly journals Increasing lipid productivity in Chlamydomonas by engineering lipid catabolism using the CRISPR-Cas9 system

2020 ◽  
Author(s):  
Thu Ha Thi Nguyen ◽  
Seunghye Park ◽  
Jooyeon Jeong ◽  
Ye Sol Shin ◽  
Sang Jun Sim ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Cell Growth ◽  
Lipid Accumulation ◽  
Sustainable Energy ◽  
Biodiesel Production ◽  
Biofuel Production ◽  
Energy Sources ◽  
Lipid Catabolism ◽  
Oleaginous Microalgae ◽  
Knockout Mutants

Abstract Background Currently, most of the attention in renewable energy industry is focused on the development of alternative, sustainable energy sources. Microalgae are a promising feedstock for biofuel production in response to the energy crisis. The use of metabolic engineering to improve yields of biofuel-related lipid components in microalgae, without affecting cell growth, is now a promising approach to develop more sustainable energy sources and to make this approach more economically feasible. Results The CRISPR-Cas9 system was successfully applied to generate a target-specific knockout of the ELT gene in Chlamydomonas reinhardtii . The target gene encodes an enzyme involved in lipid catabolism, in which the knockout phenotype impacts fatty acid degradation. As a result, the knockout mutants show up to 28.52% increased total lipid accumulation in comparison with the wild-type strain. This is also accompanied by a shift in the fatty acid composition with an increase of up to 27.2% in the C18:1 proportion. These changes do not significantly impact cell growth. Conclusion This study provides useful insights for the improvement of the oleaginous microalgae strain for biodiesel production. The acquired elt mutants showed improved lipid accumulation and productivity without compromising the growth rate.

Optimization of lipid accumulation in Pleurastrum insigne for biodiesel production

2021 ◽  
Vol 16 (10) ◽  
pp. 144-155
Author(s):  
Van Lal Michael Chhandama ◽  
Belur Kumudini Satyan
Keyword(s):  
Lipid Content ◽  
Lipid Production ◽  
Statistical Design ◽  
High Growth ◽  
High Growth Rate ◽  
Biodiesel Production ◽  
Nitrogen And Phosphorus ◽  
Biodiesel Standards ◽  
High Lipid ◽  
Different Sources

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.

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

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Francesca Martani ◽  
Letizia Maestroni ◽  
Mattia Torchio ◽  
Diletta Ami ◽  
Antonino Natalello ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Lipid Content ◽  
Lipid Production ◽  
Batch Process ◽  
Batch Cultivation ◽  
Biodiesel Production ◽  
Cellular Lipid ◽  
Lipomyces Starkeyi ◽  
Yeast Cultures ◽  
Beet Pulp

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

109 EFFECTS OF LIPOLYTIC AGENTS FORSKOLIN, EPINEPHRINE AND CAFFEINE ON EMBRYONIC DEVELOPMENT AND LIPID CONTENT OF BOVINE EMBRYOS PRODUCED IN VITRO

2009 ◽  
Vol 21 (1) ◽  
pp. 154 ◽  
Author(s):  
M. Barcelo-Fimbres ◽  
G. E. Seidel
Keyword(s):  
Amino Acids ◽  
Fatty Acid ◽  
Embryonic Development ◽  
Lipid Content ◽  
Lipid Accumulation ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Nile Red ◽  
Essential Amino Acids

The objective of this experiment was to evaluate lipid accumulation and embryonic development of bovine morulae treated with different chemicals. A total of 2619 slaughterhouse oocytes from heifers and mature cows were matured in CDM medium (similar to SOF) plus 0.5% fatty acid-free BSA and hormones (M-CDM) for 23 h at 38.5°C in 5% CO2 in air. Frozen–thawed sperm were centrifuged through a Percoll gradient and co-cultured with matured oocytes for 18 h in F-CDM (CDM+heparin). Zygotes were cultured at 38.5°C in 5% CO2/5% O2/90% N2 in CDM-1 with nonessential amino acids, 10 μm EDTA, 0.5% fatty acid free BSA, and 0.5 mm fructose. After 60 h, resulting 8-cell embryos were cultured 120 h in CDM-2 (CDM-1+essential amino acids and 2 mm fructose). A factorial design was used with 7 treatments, 2 ovary sources (cows v. heifers), and 3 bulls (A, B and C) replicated twice for each bull (6 replicates). At Day 2.5 embryo cleavage and 8-cell rates were evaluated, and on Day 6 a total of 755 morulae were randomly assigned to the 7 treatments (control, 2 and 8 mm caffeine, 1 and 4 μm epinephrine, and 10 and 40 μm forskolin). To quantify lipid accumulation, Day 7 blastocysts were fixed and stained with 1 μg mL–1 Nile red dye, after which a digital photograph of the equatorial part of the embryo (including the inner cell mass) was taken at 200×, and fluorescence intensity was measured with Image Pro software from 0 to 255 shades for each pixel (0 = no lipids; 255 = greatest lipid accumulation), as previously reported (Biol. Reprod. 2007 (Suppl. 1), 87–88). Data were analyzed by ANOVA. No differences in cleavage rates (75 v. 68 ± 3.6%) or eight cell rates (61 ± v. 57 ± 2.8%) were found for heifer v. cow oocytes (P > 0.1); however, blastocyst rates per oocyte and per 8-cell embryo were greater for cows than heifers (20 v. 10 ± 2.1%, and 68 v. 35 ± 3.8%, respectively; P < 0.05). Treatments: 2 and 8 mm caffeine produced fewer blastocysts per morula than 1 and 4 μm epinephrine, 10 and 40 μm forskolin and the control (39, 5 v. 54, 49, 48, 54 and 52 ± 5.8%; respectively) (P < 0.01). More lipid content was found in whole embryos and trophoblast of heifer-derived than cow blastocysts (P < 0.05), and forskolin resulted in less lipid content than control, caffeine- and epinephrine-treated morulae in whole embryos, embryonic mass and trophoblasts (P < 0.05; Table 1). In conclusion, mature cows were a better source of oocytes than feedlot heifers for embryonic development. High doses of caffeine were detrimental to embryos, and the addition of the lypolitic agent forskolin reduced lipid content relative to control, caffeine and epinephrine-treated embryos. Table 1.Main effect treatment means of lipid content (arbitrary fluorescence units)

scholarly journals Consortium Growth of Filamentous Fungi and Microalgae: Evaluation of Different Cultivation Strategies to Optimize Cell Harvesting and Lipid Accumulation

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3648
Author(s):  
Savienne M. F. E. Zorn ◽  
Cristiano E. R. Reis ◽  
Messias B. Silva ◽  
Bo Hu ◽  
Heizir F. De Castro
Keyword(s):  
Lipid Accumulation ◽  
Unsaturated Fatty Acids ◽  
Lipid Production ◽  
Synthetic Medium ◽  
Fungal Spores ◽  
Dry Weight ◽  
Biodiesel Production ◽  
Biomass Composition ◽  
Fungal Mycelium ◽  
Fourfold Increase

This study aims to evaluate the potential of consortium biomass formation between Mucor circinelloides, an oleaginous filamentous fungal species, and Chlorella vulgaris, in order to promote a straightforward approach to harvest microalgal cells and to evaluate the lipid production in the consortium system. A synthetic medium with glucose (2 g·L−1) and mineral nutrients essential for both fungi and algae was selected. Four different inoculation strategies were assessed, considering the effect of simultaneous vs. separate development of fungal spores and algae cells, and the presence of a supporting matrix aiming at the higher recovery of algae cell rates. The results were evaluated in terms of consortium biomass composition, demonstrating that the strategy using a mature fungal mycelium with a higher algae count may provide biomass samples with up to 79% of their dry weight as algae, still promoting recovery rates greater than 97%. The findings demonstrate a synergistic effect on the lipid accumulation by the fungal strain, at around a fourfold increase when compared to the axenic control, with values in the range of 23% of dry biomass weight. Furthermore, the fatty acid profile from the samples presents a balance between saturated and unsaturated fatty acids that is likely to present an adequate balance for applications such as biodiesel production.

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 ◽  
...  
Keyword(s):  
Cell Growth ◽  
Lipid Content ◽  
Crude Glycerol ◽  
Oleaginous Yeast ◽  
Lipid Production ◽  
Rhodosporidium Toruloides ◽  
Biodiesel Production ◽  
Lipid Yield ◽  
Stress Agent ◽  
Glycerol Consumption

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.

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