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Scott P Fulbright, Adam Robbins-Pianka, Donna Berg-Lyons, Rob Knight, Kenneth F Reardon, Stephen T Chisholm
While microalgae are a promising feedstock for production of fuels and other chemicals, a challenge for the algal bioproducts industry is obtaining consistent, robust algae growth. Algal cultures include complex bacterial communities and can be difficult to manage because specific bacteria can promote or reduce algae growth. To overcome bacterial contamination, algae growers may use closed photobioreactors designed to reduce the number of contaminant organisms. Even with closed systems, bacteria are known to enter and cohabitate, but little is known about these communities...
April 2018: Algal Research
Qingtai Chen, Dong Liu, Chongchong Wu, Kaisheng Yao, Zhiheng Li, Nan Shi, Fushan Wen, Ian D Gates
An activity-tunable biocatalyst for Nannochloropsis sp. cell-walls degradation was prepared by co-immobilization of cellulase and lysozyme on the surface of amino-functionalized magnetic nanoparticles (MNPs) employing glutaraldehyde. The competition between cellulase and lysozyme during immobilization was caused by the limited active sites of the MNPs. The maximum recovery of activities (cellulase: 78.9% and lysozyme: 69.6%) were achieved due to synergistic effects during dual-enzyme co-immobilization. The thermal stability in terms of half-life of the co-immobilized enzymes was three times higher than that in free form and had higher catalytic efficiency for hydrolysis of cell walls...
May 3, 2018: Bioresource Technology
Alexis Guionet, Bahareh Hosseini, Hidenori Akiyama, Hamid Hosano
The green algae Botryococcus braunii produces a high amount of extracellular hydrocarbon, making it a promising algae in the field of bio-fuels production. As it mainly produces squalene like hydrocarbons, cosmetic industries are also interested in its milking. Pulsed electric fields (PEF) are an innovative method allowing oil extraction from micro-algae. In common algae accumulating hydrocarbon inside cytoplasm (Chlorella vulgaris, Nannochloropsis sp., etc), electric fields can destroy cell membranes, allowing the release of hydrocarbon...
April 25, 2018: Bioelectrochemistry
Hyun Gi Koh, Nam Kyu Kang, Eun Kyung Kim, Seungjib Jeon, Sung-Eun Shin, Bongsoo Lee, Yong Keun Chang
Even though there has been much interest in genetic engineering of microalgae, its progress has been slow due to the difficulty and limitation of available techniques. Currently, genetic modification in most microalgal strains is confined to single gene transformation. Here, a multigene expression system for the oleaginous model strain Nannochloropsis salina was developed with glycine-serine-glycine spacer linked 2A self-cleaving peptides (2A) for the first time. An efficiency test of the four most widely used 2As revealed that two different types of 2As T2A and E2A have the best performance in N...
April 28, 2018: Journal of Biotechnology
Makio Yokono, Ikumi Umetani, Atushi Takabayashi, Seiji Akimoto, Ayumi Tanaka
Recently, we isolated a complex consisting of photosystem II (PSII) and light-harvesting complexes (LHCs) from Nannochloropsis granulata (Umetani et al. Photosynth Res 136:49-61, 2017). This complex contained stress-related protein, Lhcx, as a major component of LHC (Protein ID is Naga_100173g12.1), suggesting that non-photochemical quenching activities may be taking place in the PSII-LHC complex. In this study, we examined the energy transfer dynamics in the isolated LHCs and PSII-LHC complexes, and found substantial quenching capacity...
April 27, 2018: Photosynthesis Research
Priscila Tessmer Scaglioni, Massimo Blandino, Valentina Scarpino, Debora Giordano, Giulio Testa, Eliana Badiale-Furlong
Fungicides and, for the first time, microalgal phenolic extracts (MPE) from Spirulina sp. and Nannochloropsis sp. were applied on maize culture media and under field conditions to evaluate their ability to minimize Fusarium species development and fumonisin production. An in vitro assay against an F. verticillioides was carried out, using maize grains as culture medium. An open field experiment was carried out in North West Italy under naturally-infected conditions. The compared treatments were factorial combinations of: two insecticide applications (untreated control and pyrethroid against European Corn Borer), four antifungal compounds (untreated control, MPE from Spirulina sp...
April 27, 2018: Journal of Agricultural and Food Chemistry
Justine Aussant, Freddy Guihéneuf, Dagmar B Stengel
Microalgae are considered a sustainable source of high-value products with health benefits. Marine algae-derived omega-3 long-chain polyunsaturated fatty acids (LC-PUFA), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are considered dietary elements with effects on mental health, cognition enhancement, and cardiovascular protection. This study investigated the temperature effect on omega-3 LC-PUFA production in eight species of microalgae from various taxonomic groups, with a focus on achieving an optimal balance between omega-3 accumulation and efficient growth performance...
April 25, 2018: Applied Microbiology and Biotechnology
Qinhua Gan, Jiaoyun Jiang, Xiao Han, Shifan Wang, Yandu Lu
Plastid engineering offers an important tool to fill the gap between the technical and the enormous potential of microalgal photosynthetic cell factory. However, to date, few reports on plastid engineering in industrial microalgae have been documented. This is largely due to the small cell sizes and complex cell-wall structures which make these species intractable to current plastid transformation methods (i.e., biolistic transformation and polyethylene glycol-mediated transformation). Here, employing the industrial oleaginous microalga Nannochloropsis oceanica as a model, an electroporation-mediated chloroplast transformation approach was established...
2018: Frontiers in Plant Science
JaeHwang Jung, Seong-Joo Hong, Han-Byeol Kim, Geon Kim, Moosung Lee, Seungwoo Shin, SangYun Lee, Dong-Jin Kim, Choul-Gyun Lee, YongKeun Park
Microalgae are promising candidates for biofuel production due to their high lipid content. To facilitate utilization of the microalgae for biofuel, rapid quantification of the lipid contents in microalgae is necessary. However, conventional methods based on the chemical extraction of lipids require a time-consuming destructive extraction process. Here, we demonstrate label-free, non-invasive, rapid quantification of the lipid contents in individual micro-algal cells measuring the three-dimensional refractive index tomograms...
April 25, 2018: Scientific Reports
Andrea Del Pilar Sánchez-Camargo, Natalia Pleite, José Antonio Mendiola, Alejandro Cifuentes, Miguel Herrero, Bienvenida Gilbert-López, Elena Ibáñez
In the present work, the valorization of Nannochloropsis gaditana biomass is proposed within the concept of biorefinery. To this aim, high-pressure homogenization (HPH) was used to break down the strong cell wall and supercritical fluid extraction (SFE) with pure CO2 was applied as a first step to extract valuable compounds (such as non-polar lipids and pigments). Extraction of the remaining residue for the recovery of bioactive compounds was studied by means of an experimental design based on response surface methodology (RSM) employing pressurized liquid extraction (PLE) with green solvents such as water and ethanol...
April 23, 2018: Electrophoresis
Loureen Dahli, Dana Atrahimovich, Jacob Vaya, Soliman Khatib
High-density lipoprotein (HDL) plays an important role in preventing atherosclerosis. The antioxidant effect of HDL is mostly associated with paraoxonase 1 (PON1) activity. Increasing PON1 activity using nutrients might improve HDL function and quality and thus, decrease atherosclerotic risk. We previously isolated and identified a novel active compound, lyso-DGTS (C20:5,0) from Nannochloropsis sp. ethanol extract. In the present study, its effect on PON1 activities was examined and the mechanism by which the compound affects PON1 activity was explored...
April 16, 2018: BioFactors
Jun Cheng, Junchen Xu, Hongxiang Lu, Qing Ye, Jianzhong Liu, Junhu Zhou
Double paddlewheels were proposed to generate cycle flow for increasing horizontal fluid velocity between dark and light zones in a flat plate photo-bioreactor, which strengthened the mass transfer and the mixing effect to improve microalgal growth with 15% CO2 . Numerical fluid dynamics were used to simulate the cycle flow field with double paddlewheels. The local flow field measured with particle image velocimetry fitted well with the numerical simulation results. The horizontal fluid velocity in the photo-bioreactor was markedly increased from 5...
April 9, 2018: Bioresource Technology
Sam Q K Law, Ronald Halim, Peter J Scales, Gregory J O Martin
A single-step method for transesterifying and recovering lipids in concentrated slurries (ca 20% w/w solids) of ruptured microalgae is presented. A soluble Rhizomucor miehei lipase (RML) was used to directly transesterify the lipids in the marine microalgae Nannochloropsis salina. This allowed both triglycerides (TAG) and polar saponifiable lipids to be recovered as fatty acid methyl esters (FAME) using a nonpolar solvent (hexane). Up to 90 wt% of the total saponifiable lipids (SL) were converted to FAME within 24 h, approximately 75% of which was recovered in the hexane by centrifugation...
April 1, 2018: Bioresource Technology
Abdull Razak Abd Rahman, Zaidi Che Cob, Zainoddin Jamari, Abdul Majid Mohamed, Tatsuki Toda, Othman Haji Ross
Brachionus plicatilis is used to feed fish and crustacean larvae in the aquaculture industry. It is well established that the type of microalgae may influence rotifer production. This experiment was conducted to determine the effect of five different locally available microalgae species at Fisheries Research Institute (FRI), Kampung Pulau Sayak, Kedah, Malaysia on the instantaneous growth rate (μ) of rotifer. Nannochloris sp., Tetraselmis sp., Isochrysis sp., Chlorella sp., and Nannochloropsis sp. were used as feed at different algae densities (0...
March 2018: Tropical Life Sciences Research
Rudina Bleta, Benedetto Schiavo, Natale Corsaro, Paula Alexandra Costa, Alberto Giaconia, Leonardo Interrante, Eric Monflier, Giuseppe Pipitone, Anne Ponchel, Salvatore Sau, Onofrio Scialdone, Sebastien Tilloy, Alessandro Galia
Hydrothermal liquefaction (HTL) is a promising technology for the production of biocrude oil from microalgae. Although this catalyst-free technology is efficient under high-temperature and high-pressure conditions, the biocrude yield and quality can be further improved by using heterogeneous catalysts. The design of robust catalyst that preserve their performance under hydrothermal conditions will be therefore very important in the development of biorefinery technologies. In this work, we describe two different synthetic routes, i...
March 26, 2018: ACS Applied Materials & Interfaces
Min-Gyu Sung, Jong-In Han, Bongsoo Lee, Yong Keun Chang
Background: Microalgae, being a phototroph, grow in the presence of light, and utilizing photons in narrow and specific range of wavelengths. There have been numerous attempts to take advantage of this trait of wavelength-dependent growth for the purpose of increasing biomass productivity. One potential option involves wavelength conversion of sunlight. In the present study, three fluorescent dyes with blue, red, and green emission spectra were employed with the aim of improving sunlight utilization efficiency and thus enhancing biomass and lipid productivity of Nannochloropsis gaditana ...
2018: Biotechnology for Biofuels
Fan Yang, Liqing Zeng, Zhuanxi Luo, Zaosheng Wang, Fuyi Huang, Qiuquan Wang, Damjana Drobne, Changzhou Yan
Increasing concern has been focused on the potential risks associated with the trophic transfer to aquatic organisms of ambient contaminants in the presence of titanium dioxide nanoparticles (nano-TiO2 ). This study investigated the influence of nano-TiO2 on the trophic transfer of arsenic (As) from the microalgae Nannochloropsis maritima to the brine shrimp Artemia salina nauplii. We found that nano-TiO2 could significantly facilitate As sorption on N. maritima within an exposure period of 24 h, and this sorption subsequently led to higher As trophic transfer from the algae to A...
March 10, 2018: Aquatic Toxicology
Hiroki Murakami, Takashi Nobusawa, Koichi Hori, Mie Shimojima, Hiroyuki Ohta
Diacylglyceryl-N,N,N-trimethylhomoserine (DGTS) is a non-phosphorus, polar glycerolipid that is regarded as analogous to the phosphatidylcholine in bacteria, fungi, algae, and basal land plants. In some species of algae, including the stramenopile microalga Nannochloropsis oceanica, DGTS contains an abundance of eicosapentaenoic acid (EPA), which is relatively scarce in phosphatidylcholine, implying that DGTS has a unique physiological role. In this study, we addressed the role of DGTS in N. oceanica. We identified two DGTS biosynthetic enzymes that have distinct domain configurations compared to previously identified DGTS synthases...
March 19, 2018: Plant Physiology
Malgorzata Grzesiuk, Elly Spijkerman, Sabrina C Lachmann, Alexander Wacker
Pharmaceuticals are found in freshwater ecosystems where even low concentrations in the range of ng L-1 may affect aquatic organisms. In the current study, we investigated the effects of chronic exposure to three pharmaceuticals on two microalgae, a potential modulation of the effects by additional inorganic phosphorus (Pi ) limitation, and a potential propagation of the pharmaceuticals' effect across a trophic interaction. The latter considers that pharmaceuticals are bioaccumulated by algae, potentially metabolized into more (or less) toxic derivates and consequently consumed by zooplankton...
March 16, 2018: Ecotoxicology and Environmental Safety
María Huete-Ortega, Katarzyna Okurowska, Rahul Vijay Kapoore, Matthew P Johnson, D James Gilmour, Seetharaman Vaidyanathan
Background: Microalgae accumulate lipids when exposed to stressful conditions such as nutrient limitation that can be used to generate biofuels. Nitrogen limitation or deprivation is a strategy widely employed to elicit this response. However, this strategy is associated with a reduction in the microalgal growth, leading to overall poor lipid productivities. Here, we investigated the combined effect of a reduced source of nitrogen (ammonium) and super-saturating light intensities on the growth and induction of lipid accumulation in two model but diverse microalgal species, Phaeodactylum tricornutum and Nannochloropsis oceanica ...
2018: Biotechnology for Biofuels
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