Development of a Screening Method for Isolation of Microalgae Strains That Accumulate Lipids Under Nitrate-replete Conditions

2020 ◽  
Author(s):  
Tomoki Oyama ◽  
Yuichi Kato ◽  
Katsuya Satoh ◽  
Yutaka Oono ◽  
Tomohisa Hasunuma ◽  
...  
Keyword(s):  
Lipid Content ◽  
Fossil Fuels ◽  
Screening Method ◽  
Energy Resource ◽  
Biofuel Production ◽  
Sequential Procedures ◽  
High Lipid ◽  
Green Microalga ◽  
One Step ◽  
Mutant Cells

Abstract Background: Microalgae biofuels have attracted global attention as an alternative to fossil fuels as an energy resource. Microalgae generally accumulate lipids under nitrogen-depleted conditions, but cell growth is depressed under these conditions which causes decrease in lipid productivity. To realize one-step cultivation for biofuel production, microalgae that highly accumulate lipids even under nitrogen-replete conditions are needed. This study aimed to develop a screening method for microalgae mutants with high lipid content even in the presence of a nitrogen source.Results: Mutant cells were generated by irradiating the oleaginous green microalga Chlamydomonas sp. KOR1 with carbon ion beams, cultured under nitrate-replete conditions, and then subjected to FACS-based screening for lipid-rich cells. By repeatedly performing the sequential procedures of cultivation and selection, strains KAC1710 and KAC1801, which highly accumulate lipids under nitrate-replete conditions, were successfully obtained. These mutants formed significant lipid droplets in the cells even in the presence of abundant nitrate and achieved 1.5- and 2.1-fold greater lipid content compared to KOR1, respectively.Conclusion: This study developed a novel nitrogen-conditioned screening method for microalgae mutants that accumulate lipids in the presence of a nitrogen source. This method should contribute to microalgae biofuel production via one-step cultivation under nitrogen-replete conditions.

scholarly journals The Use of Urea and Kelp Waste Extract is A Promising Strategy for Maximizing the Biomass Productivity and Lipid Content in Chlorella sorokiniana

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 463 ◽  
Author(s):  
Ali Nawaz Kumbhar ◽  
Meilin He ◽  
Abdul Razzaque Rajper ◽  
Khalil Ahmed Memon ◽  
Muhammad Rizwan ◽  
...  
Keyword(s):  
Lipid Content ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Lipid Production ◽  
Total Lipid Content ◽  
Biomass Productivity ◽  
Chlorella Sorokiniana ◽  
Biofuel Production ◽  
Promising Strategy ◽  
Waste Extract

The decline in fossil fuel reserves has forced researchers to seek out alternatives to fossil fuels. Microalgae are considered to be a promising feedstock for sustainable biofuel production. Previous studies have shown that urea is an important nitrogen source for cell growth and the lipid production of microalgae. The present study investigated the effect of different concentrations of urea combined with kelp waste extract on the biomass and lipid content of Chlorella sorokiniana. The results revealed that the highest cell density, 20.36 × 107 cells−1, and maximal dry biomass, 1.70 g/L, were achieved in the presence of 0.5 g/L of urea combined with 8% kelp waste extract. Similarly, the maximum chlorophyll a, b and beta carotenoid were 10.36 mg/L, 7.05, and 3.01 mg/L, respectively. The highest quantity of carbohydrate content, 290.51 µg/mL, was achieved in the presence of 0.2 g/L of urea and 8% kelp waste extract. The highest fluorescence intensity, 40.05 × 107 cells−1, and maximum total lipid content (30%) were achieved in the presence of 0.1 g/L of urea and 8% kelp waste extract. The current study suggests that the combination of urea and kelp waste extract is the best strategy to enhance the biomass and lipid content in Chlorella sorokiniana.

scholarly journals Biomass and lipid induction strategies in microalgae for biofuel production and other applications

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Hossein Alishah Aratboni ◽  
Nahid Rafiei ◽  
Raul Garcia-Granados ◽  
Abbas Alemzadeh ◽  
José Rubén Morones-Ramírez
Keyword(s):  
Lipid Content ◽  
Large Scale ◽  
Fossil Fuels ◽  
Low Cost ◽  
Lipid Production ◽  
Arable Land ◽  
Economic Cost ◽  
Biofuel Production ◽  
Scale Production ◽  
Microalgae Biomass

Abstract The use of fossil fuels has been strongly related to critical problems currently affecting society, such as: global warming, global greenhouse effects and pollution. These problems have affected the homeostasis of living organisms worldwide at an alarming rate. Due to this, it is imperative to look for alternatives to the use of fossil fuels and one of the relevant substitutes are biofuels. There are different types of biofuels (categories and generations) that have been previously explored, but recently, the use of microalgae has been strongly considered for the production of biofuels since they present a series of advantages over other biofuel production sources: (a) they don’t need arable land to grow and therefore do not compete with food crops (like biofuels produced from corn, sugar cane and other plants) and; (b) they exhibit rapid biomass production containing high oil contents, at least 15 to 20 times higher than land based oleaginous crops. Hence, these unicellular photosynthetic microorganisms have received great attention from researches to use them in the large-scale production of biofuels. However, one disadvantage of using microalgae is the high economic cost due to the low-yields of lipid content in the microalgae biomass. Thus, development of different methods to enhance microalgae biomass, as well as lipid content in the microalgae cells, would lead to the development of a sustainable low-cost process to produce biofuels. Within the last 10 years, many studies have reported different methods and strategies to induce lipid production to obtain higher lipid accumulation in the biomass of microalgae cells; however, there is not a comprehensive review in the literature that highlights, compares and discusses these strategies. Here, we review these strategies which include modulating light intensity in cultures, controlling and varying CO2 levels and temperature, inducing nutrient starvation in the culture, the implementation of stress by incorporating heavy metal or inducing a high salinity condition, and the use of metabolic and genetic engineering techniques coupled with nanotechnology.

scholarly journals Rapid Lipid Content Screening in Neochloris Oleoabundans by Carbon-Based Dielectrophoresis

2021 ◽  
Vol 4 (1) ◽  
pp. 41
Author(s):  
Cynthia M. Galicia-Medina ◽  
Matías Vázquez-Piñón ◽  
Sergio Camacho-León ◽  
Gibran S. Alemán-Nava ◽  
Roberto C. Gallo-Villanueva ◽  
...  
Keyword(s):  
Lipid Content ◽  
Lipid Production ◽  
Biofuel Production ◽  
Neochloris Oleoabundans ◽  
Atmospheric Concentration ◽  
Machine Material ◽  
Fixation Rate ◽  
Screening Process ◽  
High Lipid

The use of microalgae as a biomass source for biofuel production has drawn the attention of many scientists due to several associated environmental advantages over conventional terrestrial crops, including microalgae growing using wastewaters and a higher CO2 fixation rate, contributing to the reduction of atmospheric concentration. Consequently, a reliable cytoplasmic lipid screening process in microalgae is a valuable asset for harvesting optimization in mass production processes. In this study, the heterogeneous cytoplasmic lipid content of Neochloris oleoabundans was dielectrophoretically assorted in a microfluidic device using castellated carbon microelectrodes. The experiments carried out over a wide frequency window (100 kHz to 30 MHz) at a fixed amplitude of 7 VPP showed a significant contrast between the dielectrophoretic behavior of high lipid content and low lipid content cells at the low frequency range (100–800 kHz). A weak response for the mid and high frequency ranges (1–30 MHz) was also identified for high and low lipid content samples, allowing one to establish an electrokinetic footprint of the studied strain. These results suggest that the development of a reliable screening process for harvesting optimization is possible through a fast and straightforward mechanism, such as dielectrophoresis, which is a low-cost and easy-to-machine material that employs glassy carbon. The experimental setup in this study involved in vitro culturing of nitrogen-replete (N+) and nitrogen-deplete (N-) cell suspensions to promote low and high lipid production in cells, respectively. Cell populations were monitored using spectrophotometry, and the resulting lipid development among cells was quantified by Nile red fluorescence.

scholarly journals Bacterial diketopiperazines stimulate diatom growth and lipid accumulation

2021 ◽  
Author(s):  
John Sittmann ◽  
Munhyung Bae ◽  
Emily Mevers ◽  
Muzi Li ◽  
Andrew Quinn ◽  
...  
Keyword(s):  
Lipid Content ◽  
Phaeodactylum Tricornutum ◽  
Photosynthetic Efficiency ◽  
Biofuel Production ◽  
Marine Diatom ◽  
Diatom Cell ◽  
Marine Microbes ◽  
Bacillus Cereus Group ◽  
Cell Lysate ◽  
High Lipid

Abstract Diatoms are photosynthetic microalgae that fix a significant fraction of the world’s carbon. Because of their photosynthetic efficiency and high-lipid content, diatoms are priority candidates for biofuel production. Here, we report that sporulating Bacillus thuringiensis and other members of the Bacillus cereus group, when in co-culture with the marine diatom Phaeodactylum tricornutum, significantly increase diatom cell count. Bioassay-guided purification of the mother cell lysate of B. thuringiensis led to the identification of two diketopiperazines (DKPs) that both stimulate P. tricornutum growth and increase its lipid content. These findings may be exploited to enhance P. tricornutum growth and microalgae-based biofuel production. As increasing numbers of DKPs are isolated from marine microbes, the work gives potential clues to bacterial-produced growth factors for marine microalgae.

A Review on Biodiesel Production: Breeding Technologies of Microalgae Containing Rich Lipid

2014 ◽  
Vol 472 ◽  
pp. 759-763
Author(s):  
Chao Ma ◽  
Bing Feng Liu ◽  
Hong Yu Ren ◽  
Nan Qi Ren
Keyword(s):  
Growth Rate ◽  
Lipid Content ◽  
Production Cost ◽  
Fossil Fuels ◽  
Biodiesel Production ◽  
High Lipid ◽  
Key Factor ◽  
Production Technologies ◽  
Photosynthetic Microorganisms ◽  
Fast Growth Rate

Among different biodiesel production technologies, microalgae biodiesel production has exhibited largest potential as an substitute of fossil fuels. Microalgae are effective photosynthetic microorganisms and ideal materials for biodiesel production because they have many advantages, such as the high lipid content, fast growth rate and good adaptability. Most key factor for the industrialization of microalgae biodiesel production is selecting the microalgae with rich lipid, which determines the production cost of microalgae biodiesel. The different breeding technologies of microalgae can significantly shorten the breeding time, reduce the production cost and obtain expected strains. The prospect of microalgael application in biodiesel production was also discussed.

scholarly journals Characterization and identification of freshwater microalgal strains toward biofuel production

BioResources ◽  
2011 ◽  
Vol 7 (1) ◽  
pp. 686-695
Author(s):  
Xun Yang ◽  
Pinghuai Liu ◽  
Zongdi Hao ◽  
Jie Shi ◽  
Sen Zhang
Keyword(s):  
Oleic Acid ◽  
Lipid Content ◽  
Biomass Concentration ◽  
Lipid Productivity ◽  
Biodiesel Production ◽  
Biofuel Production ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Chlorella Sp ◽  
High Lipid

Fifty-three algal cultures were isolated from freshwater lakes in Hainan, China. Four microalgal isolates were selected because they could be successfully cultivated at high density and demostrated a strong fluorescence after being stained with nile red. These cultures were identified as strains of Chlorella sp. C11, Chlamydomonas reinhardtii C22, Monoraphidium dybowskii C29, and Chlorella sp. HK12 through microscopic and 18S rDNA analysis. Under similar conditions, the lipid productivity of Chlorella sp. C11, Chla. reinhardtii C22, M. dybowskii C29 , and Chlorella sp. HK12 were 1.88, 2.79, 2.00, and 3.25 g L-1, respectively. Chla. reinhardtii C22 yielded a higher lipid content (51%), with a lower biomass concentration (5.47 g dwt L-1). Chlorella sp. HK12 reached a growth rate of 0.88 day-1 at OD540nm and yielded a biomass concentration of 7.56 g dwt L-1, with a high lipid content of 43%. Gas chromatography/ mass spectrometry analysis indicated that lipid fraction mainly comprises hydrocarbons including palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acids. Our results suggest that Chlorella sp. HK12 is a promising species for biodiesel production, because of its high lipid productivity and a relatively high content of oleic acid.

Screening Method for Lipid-Content Microalgae Based on Sulfo-Phospho-Vanillin Reaction

2012 ◽  
Vol 610-613 ◽  
pp. 3532-3535 ◽  
Author(s):  
Zong Di Hao ◽  
Ping Huai Liu ◽  
Xun Yang ◽  
Jie Shi ◽  
Sen Zhang
Keyword(s):  
Lipid Content ◽  
Neutral Lipids ◽  
Screening Method ◽  
Colorimetric Method ◽  
Total Lipid Content ◽  
Dry Weight ◽  
Traditional Methods ◽  
Microalgal Oil ◽  
Microalgal Culture ◽  
High Lipid

Studies that address the use of microalgae as biofuels often require the frequent measurement of total lipid content. Traditional methods for the quantification of lipid are time-consuming or involve the use of expensive analytical equipment that is not available in many labs. Here we investigated microalgal culture as the starting material and simple, colorimetric method for quantitative measurement of neutral lipids in microalgae with a relatively high correlation coefficient (R2=0.9038) between gravimetric and spectrophotometric quantification. Linear responses for triolein, vegetable oil and microalgal oil in a concentration range between 0.1 and 1 mg/l were observed. Using this method, Monoraphidium pusillum were screened out of several microalgal strains with the highest lipid content (25.52% dry weight). The color reaction for quantitation of microalgal lipids has significant advantages over traditional methods for screening of high lipid-content strains. Our data implied that the sensitivity and versatility enable this method a useful tool in screening of lipid-content microalgae.

scholarly journals Bacterially produced small molecules stimulate diatom growth

2020 ◽  
Author(s):  
John Sittmann ◽  
Munhyung Bae ◽  
Emily Mevers ◽  
Muzi Li ◽  
Andrew Quinn ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Lipid Content ◽  
Nutrient Recycling ◽  
Biofuel Production ◽  
Marine Diatom ◽  
Rna Seq ◽  
Marine Microbes ◽  
Iron Starvation ◽  
High Lipid ◽  
Small Set

AbstractDiatoms are photosynthetic microalgae that fix a significant fraction of the world’s carbon. Because of their photosynthetic efficiency and high-lipid content, diatoms are priority candidates for biofuel production. Here, we report that sporulating Bacillus thuringiensis when in co-culture with a marine diatom Phaeodactylum tricornutum significantly increases the diatom cell count. Bioassay-guided purification led to the identification of two diketopiperazines (DKPs) that both stimulate P. tricornutum growth and increase its lipid content. RNA-seq analysis revealed upregulation of a small set of P. tricornutum genes involved in iron starvation response and nutrient recycling when DKP was added to the diatom culture. This work demonstrates that two DKPs produced by a bacterium could positively impact P. tricornutum growth and lipid content, offering new approaches to enhance P. tricornutum-based biofuel production. As increasing numbers of DKPs are isolated from marine microbes, the work gives potential clues to bacterially produced growth factors for marine microalgae.One sentence summaryTwo diketopiperazines (DKPs) produced by sporulating bacterium Bacillus thuringiensis stimulate diatom P. tricornutum growth and increase diatom lipid content.

scholarly journals Monodopsis and Vischeria genomes elucidate the biology of eustigmatophyte algae

2021 ◽  
Author(s):  
Hsiao-Pei Yang ◽  
Marius Wenzel ◽  
Duncan A Hauser ◽  
Jessica M Nelson ◽  
Xia Xu ◽  
...  
Keyword(s):  
Synthetic Biology ◽  
Lipid Content ◽  
Biofuel Production ◽  
Terpenoid Biosynthesis ◽  
High Quality ◽  
Spliced Leader ◽  
High Lipid ◽  
Trans Splicing ◽  
Genome Assemblies ◽  
Simple Repeats

Members of eustigmatophyte algae, especially Nannochloropsis, have been tapped for biofuel production owing to their exceptionally high lipid content. While extensive genomic, transcriptomic, and synthetic biology toolkits have been made available for Nannochloropsis, very little is known about other eustigmatophytes. Here we present three near-chromosomal and gapless genome assemblies of Monodopsis (60 Mb) and Vischeria (106 Mb), which are the sister groups to Nannochloropsis. These genomes contain unusually high percentages of simple repeats, ranging from 12% to 21% of the total assembly size. Unlike Nannochloropsis, LINE repeats are abundant in Monodopsis and Vischeria and might constitute the centromeric regions. We found that both mevalonate and non-mevalonate pathways for terpenoid biosynthesis are present in Monodopsis and Vischeria, which is different from Nannochloropsis that has only the latter. Our analysis further revealed extensive spliced leader trans-splicing in Monodopsis and Vischeria at 36-61% of genes. Altogether, the high-quality genomes of Monodopsis and Vischeria not only serve as the much-needed outgroups to advance Nannochloropsis research, but also shed new light on the biology and evolution of eustigmatophyte algae.

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