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 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.

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 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.

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 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.

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 Transcriptomic Changes Induced by Deletion of Transcriptional Regulator GCR2 on Pentose Sugar Metabolism in Saccharomyces cerevisiae

2021 ◽  
Vol 9 ◽  
Author(s):  
Minhye Shin ◽  
Heeyoung Park ◽  
Sooah Kim ◽  
Eun Joong Oh ◽  
Deokyeol Jeong ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Xylose Fermentation ◽  
Sugar Metabolism ◽  
Pentose Phosphate ◽  
Biofuel Production ◽  
Rna Seq ◽  
Loss Of Function ◽  
Lignocellulosic Biofuel ◽  
Pentose Sugar ◽  
Transcriptomic Changes

Being a microbial host for lignocellulosic biofuel production, Saccharomyces cerevisiae needs to be engineered to express a heterologous xylose pathway; however, it has been challenging to optimize the engineered strain for efficient and rapid fermentation of xylose. Deletion of PHO13 (Δpho13) has been reported to be a crucial genetic perturbation in improving xylose fermentation. A confirmed mechanism of the Δpho13 effect on xylose fermentation is that the Δpho13 transcriptionally activates the genes in the non-oxidative pentose phosphate pathway (PPP). In the current study, we found a couple of engineered strains, of which phenotypes were not affected by Δpho13 (Δpho13-negative), among many others we examined. Genome resequencing of the Δpho13-negative strains revealed that a loss-of-function mutation in GCR2 was responsible for the phenotype. Gcr2 is a global transcriptional factor involved in glucose metabolism. The results of RNA-seq confirmed that the deletion of GCR2 (Δgcr2) led to the upregulation of PPP genes as well as downregulation of glycolytic genes, and changes were more significant under xylose conditions than those under glucose conditions. Although there was no synergistic effect between Δpho13 and Δgcr2 in improving xylose fermentation, these results suggested that GCR2 is a novel knockout target in improving lignocellulosic ethanol production.

scholarly journals Kinetics of Anaerobic Digestion of Dairy Fat Waste with Saponification Pre-Treatment

2019 ◽  
Vol 13 (2) ◽  
pp. 112 ◽  
Author(s):  
Rifki Wahyu Kurnianto ◽  
Wiratni Budhijanto ◽  
Rochim Bakti Cahyono
Keyword(s):  
Anaerobic Digestion ◽  
Lipid Content ◽  
Alternative Energy ◽  
Organic Waste ◽  
High Lipid Content ◽  
Dairy Fat ◽  
High Lipid ◽  
Pre Treatment ◽  
Kinetics Of ◽  
Floating Layer

Anaerobic digestion has been an attractive field of research in the era of energy crisis. Biogas, which is the product of anaerobic digestion, provides alternative energy, while at the same time it also prevents pollution due to organic waste accumulation. Among various organic wastes, dairy fat waste is a potential substrate for anaerobic digestion. Fat waste has high theoretical biogas potential because of its high lipid content. However, anaerobic digestion of organic waste with high lipid content is quite challenging. The main obstacle in anaerobic digestion of fat waste is its tendency to form insoluble floating layer on top of the liquid phase. This phenomenon hinders the access of hydrolytic bacteria to the substrate. Saponification is one of the methods to increase the solubility of the floating layer and hence to improve the availability of substrate for the bacteria. Saponification changes the lipid content into soap which has both polar and non-polar functional groups and the polar side will increase the solubility of the substrate in water. This study evaluated the effect of different dosage of base added as the reactant during saponification pre-treatment on the productivity of anaerobic digestion of dairy fat waste. The kinetics of the anaerobic digestion process was analyzed by mean of mathematical model. The variations of the alkaline dosages studied for saponification pre-treatment were 0.04 mol base/g sCOD; 0.02 mol base/g sCOD; and no pre-treatment for control reactor. This study proved that saponification increased the solubility of dairy fat waste. This result was confirmed by the hydrolysis constant value (kH) of 0.00782/day for reactor with saponification, which was twenty times of magnitude higher than the kH value of 0.00032/day in the reactor without saponification. However, the exposure to high pH during the saponification pre-treatment might somewhat inhibit indigenous acidogenic bacteria in the waste which results in lower methane yield in the reactors with saponification to be compared to the control reactor. A B S T R A KPeruraian anaerobik merupakan salah satu bidang riset yang sangat menarik perhatian dalam era krisis energi. Biogas tidak hanya menyediakan energi alternatif, tetapi juga dapat mencegah pencemaran akibat limbah organik. Limbah lemak susu adalah substrat yang potensial untuk proses peruraian anaerobik karena memiliki potensi biogas teoritis yang tinggi akibat kandungan lemaknya yang tinggi. Namun, peruraian anaerobik dari limbah organik dengan kandungan lemak yang tinggi memiliki tantangan tersendiri. Hambatan utama dalam peruraian anaerobik dari limbah lemak susu adalah kecenderungan untuk membentuk lapisan padatan yang tidak larut dan mengapung di bagian atas fase cair. Fenomena ini menghambat akses bakteri hidrolisis terhadap substrat. Saponifikasi adalah salah satu cara untuk meningkatkan kelarutan lapisan padatan tersebut, sehingga meningkatkan ketersediaan substrat untuk bakteri. Saponifikasi akan mengubah kandungan lemak menjadi sabun yang memiliki gugus fungsi polar maupun non-polar. Gugus fungsi yang bersifat polar akan meningkatkan kelarutan substrat dalam air. Studi ini mengevaluasi pengaruh dari berbagai dosis larutan basa yang ditambahkan sebagai reaktan selama perlakuan awal saponifikasi terhadap peruraian anaerobik limbah lemak susu. Kinetika proses peruraian anaerobik dianalisis dengan menggunakan model matematika. Variasi dosis yang diamati pengaruhnya untuk perlakuan awal saponifikasi adalah 0,04 mol basa/g sCOD; 0,02 mol basa/g sCOD; dan nol (tanpa perlakuan awal saponifikasi). Dari penelitian ini, terbukti bahwa saponifikasi berhasil meningkatkan kelarutan limbah lemak susu dan juga ditunjukkan oleh nilai konstanta hidrolisis (kH) 0,00782/hari lebih tinggi dua puluh kali lipat dibandingkan dengan nilai kH 0,00032/hari pada reaktor tanpa saponifikasi. Akan tetapi, penelitian ini juga mengindikasikan bahwa bakteri asidogenik bawaan substrat terhambat kinerjanya oleh paparan pH yang tinggi selama perlakuan awal saponifikasi berlangsung sehingga hasil gas metan yang diperoleh lebih rendah daripada reaktor kontrol.

scholarly journals Investigation of Drosophila fruitless neurons that express Dpr/DIP cell adhesion molecules

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Savannah G Brovero ◽  
Julia C Fortier ◽  
Hongru Hu ◽  
Pamela C Lovejoy ◽  
Nicole R Newell ◽  
...  
Keyword(s):  
Courtship Behavior ◽  
Cell Number ◽  
Neuronal Morphology ◽  
Immunoglobulin Superfamily ◽  
Rna Seq ◽  
Reproductive Behaviors ◽  
Behavioral Studies ◽  
Genes Encoding ◽  
Genomic Studies ◽  
Small Set

Drosophila reproductive behaviors are directed by fruitless neurons. A reanalysis of genomic studies shows that genes encoding dpr and DIP Immunoglobulin superfamily (IgSF) members are expressed in fru P1 neurons. We find that each fru P1 and dpr/DIP (fru P1 ∩ dpr/DIP) overlapping expression pattern is similar in both sexes, but there are dimorphisms in neuronal morphology and cell number. Behavioral studies of fru P1 ∩ dpr/DIP perturbation genotypes indicates that the mushroom body functions together with the lateral protocerebral complex to direct courtship behavior. A single-cell RNA-seq analysis of fru P1 neurons shows that many DIPs have high expression in a small set of neurons, whereas the dprs are often expressed in a larger set of neurons at intermediate levels, with a myriad of dpr/DIP expression combinations. Functionally, we find that perturbations of sex hierarchy genes and of DIP-ε change the sex-specific morphologies of fru P1 ∩ DIP-α neurons.

Sign in / Sign up

Export Citation Format

Share Document