scholarly journals Water reuse and growth inhibition mechanisms for cultivation of microalga Euglena gracilis

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Mingcan Wu ◽  
Ming Du ◽  
Guimei Wu ◽  
Feimiao Lu ◽  
Jing Li ◽  
...  
Keyword(s):  
Fresh Water ◽  
Euglena Gracilis ◽  
Water Reuse ◽  
Large Scale ◽  
Growth Inhibitor ◽  
Growth Inhibitors ◽  
Aromatic Rings ◽  
Potential Growth ◽  
Control Growth ◽  
Pi Systems

Abstract Background Microalgae can contribute to more than 40% of global primary biomass production and are suitable candidates for various biotechnology applications such as food, feed products, drugs, fuels, and wastewater treatment. However, the primary limitation for large-scale algae production is the fact that algae requires large amounts of fresh water for cultivation. To address this issue, scientists around the world are working on ways to reuse the water to grow microalgae so that it can be grown in successive cycles without the need for fresh water. Results In this study, we present the results when we cultivate microalgae with cultivation water that is purified and reused. Specifically, we purify the cultivation water using an ultrafiltration membrane (UFM) treatment and investigate how this treatment affects: the biomass and biochemical components of the microalgae; characteristics of microalgae growth inhibitors; the mechanism whereby potential growth inhibitors are secreted (followed using metabolomics analysis); the effect of activated carbon (AC) treatment and advanced oxidation processes (AOPs) on the removal of growth inhibitors of Euglena gracilis. Firstly, the results show that E. gracilis can be only cultivated through two growth cycles with water that has been filtered and reused, and the growth of E. gracilis is significantly inhibited when the water is used a third time. Secondly, as the number of reused water cycles increases, the Cl− concentration gradually increases in the cultivation water. When the Cl− concentration accumulates to a level of fivefold higher than that of the control, growth of E. gracilis is inhibited as the osmolality tolerance range is exceeded. Interestingly, the osmolality of the reused water can be reduced by replacing NH4Cl with urea as the source of nitrogen in the cultivation water. Thirdly, E. gracilis secretes humic acid (HA)—which is produced by the metabolic pathways for valine, leucine, and isoleucine biosynthesis and by linoleic acid metabolism—into the cultivation water. Because HA contains large fluorescent functional groups, specifically extended π(pi)-systems containing C=C and C=O groups and aromatic rings, we were able to observe a positive correlation between HA concentration and the rate of inhibition of E. gracilis growth using fluorescence spectroscopy. Moreover, photosynthetic efficiency is adversely interfered by HA, thereby reductions in the synthetic efficiency of paramylon and lipid in E. gracilis. In this way, we are able to confirm that HA is the main growth inhibitor of E. gracilis. Finally, we verify that all the HA is removed or converted into nutrients efficiently by AC or UV/H2O2/O3 treatments, respectively. As a result of these treatments, growth of E. gracilis is restored (AC treatment) and the amount of biomass is promoted (UV/H2O2/O3 treatment). Conclusions These studies have important practical and theoretical significance for the cyclic cultivation of E. gracilis and for saving water resources. Our work may also provide a useful reference for other microalgae cultivation.

Ocean Salinity Aspects of the Ningaloo Niño

2021 ◽  
pp. 1
Author(s):  
Yaru Guo ◽  
Yuanlong Li ◽  
Fan Wang ◽  
Yuntao Wei
Keyword(s):  
Fresh Water ◽  
Large Scale ◽  
Southern Oscillation ◽  
Regional Climate ◽  
Ocean Model ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Surface Salinity ◽  
Near Surface ◽  
Ocean Salinity

AbstractNingaloo Niño – the interannually occurring warming episode in the southeast Indian Ocean (SEIO) – has strong signatures in ocean temperature and circulation and exerts profound impacts on regional climate and marine biosystems. Analysis of observational data and eddy-resolving regional ocean model simulations reveals that the Ningaloo Niño/Niña can also induce pronounced variability in ocean salinity, causing large-scale sea surface salinity (SSS) freshening of 0.15–0.20 psu in the SEIO during its warm phase. Model experiments are performed to understand the underlying processes. This SSS freshening is mutually caused by the increased local precipitation (~68%) and enhanced fresh-water transport of the Indonesian Throughflow (ITF; ~28%) during Ningaloo Niño events. The effects of other processes, such as local winds and evaporation, are secondary (~18%). The ITF enhances the southward fresh-water advection near the eastern boundary, which is critical in causing the strong freshening (> 0.20 psu) near the Western Australian coast. Owing to the strong modulation effect of the ITF, SSS near the coast bears a higher correlation with the El Niño-Southern Oscillation (0.57, 0.77, and 0.70 with Niño-3, Niño-4, and Niño-3.4 indices, respectively) than sea surface temperature (-0.27, -0.42, and -0.35) during 1993-2016. Yet, an idealized model experiment with artificial damping for salinity anomaly indicates that ocean salinity has limited impact on ocean near-surface stratification and thus minimal feedback effect on the warming of Ningaloo Niño.

scholarly journals In VitroInhibition ofHelicobacter pyloriGrowth by Redox Cycling Phenylaminojuglones

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Julio Benites ◽  
Héctor Toledo ◽  
Felipe Salas ◽  
Angélica Guerrero ◽  
David Rios ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Antibacterial Activity ◽  
Active Compound ◽  
Metabolic Pathways ◽  
Growth Inhibitor ◽  
Growth Inhibitors ◽  
Design Synthesis ◽  
H Pylori

Infection byHelicobacter pyloriincreases 10 times the risk of developing gastric cancer. Juglone, a natural occurring 1,4-naphthoquinone, preventsH. pylorigrowth by interfering with some of its critical metabolic pathways. Here, we report the design, synthesis, andin vitroevaluation of a series of juglone derivatives, namely, 2/3-phenylaminojuglones, as potentialH. pylorigrowth inhibitors. Results show that 5 out of 12 phenylaminojuglones (at 1.5 μg/mL) were 1.5–2.2-fold more active than juglone. Interestingly, most of the phenylaminojuglones (10 out of 12) were 1.1–2.8 fold more active than metronidazole, a knownH. pylorigrowth inhibitor. The most active compound, namely, 2-((3,4,5-trimethoxyphenyl)amino)-5-hydroxynaphthalene-1,4-dione 7, showed significant higher halo of growth inhibitions (HGI = 32.25 mm) to that of juglone and metronidazole (HGI = 14.50 and 11.67 mm). Structural activity relationships of the series suggest that the nature and location of the nitrogen substituents in the juglone scaffold, likely due in part to their redox potential, may influence the antibacterial activity of the series.

scholarly journals Effect of Protocatechuic Acid on Euglena gracilis Growth and Accumulation of Metabolites

2020 ◽  
Vol 12 (21) ◽  
pp. 9158
Author(s):  
Xiaomiao Tan ◽  
Jiangyu Zhu ◽  
Minato Wakisaka
Keyword(s):  
Euglena Gracilis ◽  
Large Scale ◽  
Protocatechuic Acid ◽  
Biomass Yield ◽  
Growth Promotion ◽  
Low Cost ◽  
Cost Effective ◽  
Control Group ◽  
Biological Functions ◽  
First Time

The development of efficient, environmentally friendly, low-cost approaches used to boost the growth of microalgae is urgently required to meet the increasing demands for food supplements, cosmetics, and biofuels. In this study, the growth promotion effects of protocatechuic acid (PCA) in the freshwater microalga Euglena gracilis were confirmed for the first time. PCA is a simple phenolic compound derived from natural plants and has a range of biological functions. The highest biomass yield, 3.1-fold higher than that of the control, used at 1.3 g·L−1, was obtained at 800 mg·L−1 of PCA. The yields of the metabolites chlorophyll a, carotenoids, and paramylon in the presence of PCA at 800 mg·L−1 were 3.1, 3.3, and 1.7 times higher than those of the control group, respectively. The highest paramylon yield was achieved at a lower dosage of PCA (100 mg·L−1), which is considered to be feasible for economic paramylon production. The growth and biosynthesis of metabolites stimulated by phytochemicals such as PCA could be an efficient and cost-effective strategy to enhance the productivity of microalgae in large-scale cultivations.

scholarly journals Stratigraphy, stable isotopes and salinity in multi-year sea ice from the rift area, south George VI Ice Shelf, Antarctic Peninsula

1991 ◽  
Vol 37 (127) ◽  
pp. 357-367
Author(s):  
J.-L. Tison ◽  
E. M. Morris ◽  
R. Souchez ◽  
J. Jouzel
Keyword(s):  
Stable Isotopes ◽  
Sea Ice ◽  
Fresh Water ◽  
Large Scale ◽  
Sea Water ◽  
Ice Core ◽  
Ice Shelf ◽  
The Core ◽  
Brackish Ice ◽  
Ice Production

AbstractResults from a detailed profile in a 5.54 m multi-year sea-ice core from the rift area in the southern part of George VI Ice Shelf are presented. Stratigraphy, stable isotopes and Na content are used to investigate the growth processes of the ice cover and to relate them to melting processes at the bottom of the ice shelf.The thickest multi-year sea ice in the sampling area appears to be second-year sea ice that has survived one melt season. Combined salinity/stable-isotope analyses show large-scale sympathetic fluctuations that can be related to the origin of the parent water. Winter accretion represents half of the core length and mainly consists of frazil ice of normal sea-water origin. However, five major dilution events of sea water, with fresh-water input from the melting base of the ice shelf reaching 20% on two occasions, punctuate this winter accretion. Two of them correspond to platelet-ice production, which is often related to the freezing of ascending supercooled water from the bottom of the ice shelf.Brackish ice occurs between 450 and 530 cm in the core. It is demonstrated that this results from the freezing of brackish water (Jeffries and others, 1989) formed by mixing of normal sea water with melted basal shelf ice, with dilution percentages of maximum 80% fresh water.

A Comparative Risk Assessment for Listeria monocytogenes in Prepackaged versus Retail-Sliced Deli Meat

2010 ◽  
Vol 73 (4) ◽  
pp. 612-619 ◽  
Author(s):  
SARAH ENDRIKAT ◽  
DANIEL GALLAGHER ◽  
RÉGIS POUILLOT ◽  
HEATHER HICKS QUESENBERRY ◽  
DAVID LaBARRE ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Sensitivity Analysis ◽  
Listeria Monocytogenes ◽  
Shelf Life ◽  
Risk Ratio ◽  
Growth Inhibitor ◽  
Assessment Model ◽  
Growth Inhibitors ◽  
Comparative Risk ◽  
Inspection Service

Deli meat was ranked as the highest-risk ready-to-eat food vehicle of Listeria monocytogenes within the 2003 U.S. Food and Drug Administration and U.S. Department of Agriculture, Food Safety and Inspection Service risk assessment. The comparative risk of L. monocytogenes in retail-sliced versus prepackaged deli meats was evaluated with a modified version of this model. Other research has found that retail-sliced deli meats have both higher prevalence and levels of L. monocytogenes than have product sliced and packaged at the manufacturer level. The updated risk assessment model considered slicing location as well as the use of growth inhibitors. The per annum comparative risk ratio for the number of deaths from retail-sliced versus prepackaged deli meats was found to be 4.89, and the per-serving comparative risk ratio was 4.27. There was a significant interaction between the use of growth inhibitors and slicing location. Almost 70% of the estimated deaths occurred from retail-sliced product that did not possess a growth inhibitor. A sensitivity analysis, assessing the effect of the model's consumer storage time and shelf life assumptions, found that even if retail-sliced deli meats were stored for a quarter of the time prepackaged deli meats were stored, retail-sliced product is 1.7 times more likely to result in death from listeriosis. Sensitivity analysis also showed that the shelf life assumption had little effect on the comparative risk ratio.

New Non-Grid Wind Power Desalination Systems Research

2014 ◽  
Vol 488-489 ◽  
pp. 970-974
Author(s):  
Gang Wang ◽  
Jian Zhong Shi
Keyword(s):  
Water Resources ◽  
Wind Power ◽  
Fresh Water ◽  
Large Scale ◽  
Sea Water ◽  
Rapid Development ◽  
Clean Energy ◽  
High Energy ◽  
Water Desalination ◽  
Systems Research

the large-scale application of non-grid-connected wind power in sea water desalination industry has not only solved the difficulty in grid connection of wind power, but also can be an inexhaustible clean energy supply for the sea water desalination. Such application, breaking through the traditional sea water desalination technology and wind power development ideas and realizing the 100% local use of renewable energies, is a perfect combination of the new energy industry and the power consumption industry. The large-scale industrialization application of non-grid-connected wind power sea water desalination can not only maximize the efficiency of wind power and realize the unification of social benefit, environmental benefit and economic benefit, but also is of great strategic significance in accelerating the transformation of the economic development mode of China, and meanwhile, plays a leading role in the diversified development of the world wind power industry. 1. High-energy consumption factors restrict the development of sea water desalination Sea water desalination is a source-opening incremental technology for realizing the utilization of water resources, which can increase the total amount of fresh water and is not limited by time, space and climate with good water quality, and can guarantee the stable water supply of drinking water for coastal residents and industrial water supplementation. Since sea water desalination is the substitutional and incremental technology of fresh water resources, many countries are attaching more and more importance on it. With the rapid development of the economy and society of China, especially with the acceleration of urbanization, some coastal developed areas and large cities near the sea are having a greater and greater demand on water resources. In this condition, the development of sea water desalination has a great strategic significance in the supplementation of water resources in the sustainable development process of these areas[1,2].

The Comparison between Boron Carbide (B4C) with other Common Inhibitors on Physical and Mechanical Properties of WC/Co

2012 ◽  
Vol 05 ◽  
pp. 102-110 ◽  
Author(s):  
H. Tamizifar ◽  
A.M. Hadian ◽  
M. Tamizifar
Keyword(s):  
Boron Carbide ◽  
Vanadium Carbide ◽  
Sintering Temperature ◽  
Physical And Mechanical Properties ◽  
Growth Inhibitor ◽  
Hard Metal ◽  
Growth Inhibitors ◽  
Fine Grained ◽  
Hard Metals ◽  
Boron Carbide B4c

The hardness, toughness and sum of cracks measurement of fine-grained WC - Co hard metals were studied. Thirty commercial and experimental hard metal grades with different additives such as boron carbide ( B 4 C ), vanadium carbide ( VC ), chromium carbide ( Cr 3 C 2) and silicon carbide ( SiC ) were prepared in a commercial sinter HIP furnace. Physical, mechanical and microstructure properties were investigated to build up a representative hardness/sum of cracks measurement band. This band was then used to estimate the most effective sintering temperature and the amount of each additives. Afterwards, influence of grain growth inhibitors in optimum condition were compared. The results showed that the grades, doped with B 4 C and VC as growth inhibitor exhibits more hardness than other comparable doped alloys. However, Cr 3 C 2 is favorable in toughness improvement.

Research Progress on the Reduction and Utilization of RO Concentrated Brine from Desalination Plants

2013 ◽  
Vol 821-822 ◽  
pp. 1098-1101
Author(s):  
Wei Xing Li ◽  
Jing Huan Ma ◽  
Ying Liu ◽  
Qing Tong Ren ◽  
Zhan Sheng Ma
Keyword(s):  
Reverse Osmosis ◽  
Fresh Water ◽  
Brackish Water ◽  
Large Scale ◽  
Marine Ecosystems ◽  
Research Progress ◽  
Research Focus ◽  
Actual Application ◽  
Desalination Plants

Reverse Osmosis (RO) is an effective method to get fresh water from seawater or brackish water. The uncontrolled discharge of RO concentrated brine can contaminate water aquifers and damage marine ecosystems. The techniques to treat or utilize the rejected brine are the research focus in recent years. This paper tried to give an overview of latest development in this filed in order to provide references for its actual application in large-scale engineering.

Nanofiltration technology in water treatment and reuse: applications and costs

2015 ◽  
Vol 71 (3) ◽  
pp. 309-319 ◽  
Author(s):  
Arash Shahmansouri ◽  
Christopher Bellona
Keyword(s):  
Wastewater Treatment ◽  
Cost Estimation ◽  
Water Reuse ◽  
Large Scale ◽  
Industrial Applications ◽  
Estimation Methods ◽  
Seawater Desalination ◽  
Labor Costs ◽  
Water And Wastewater Treatment ◽  
Water And Wastewater

Nanofiltration (NF) is a relatively recent development in membrane technology with characteristics that fall between ultrafiltration and reverse osmosis (RO). While RO membranes dominate the seawater desalination industry, NF is employed in a variety of water and wastewater treatment and industrial applications for the selective removal of ions and organic substances, as well as certain niche seawater desalination applications. The purpose of this study was to review the application of NF membranes in the water and wastewater industry including water softening and color removal, industrial wastewater treatment, water reuse, and desalination. Basic economic analyses were also performed to compare the profitability of using NF membranes over alternative processes. Although any detailed cost estimation is hampered by some uncertainty (e.g. applicability of estimation methods to large-scale systems, labor costs in different areas of the world), NF was found to be a cost-effective technology for certain investigated applications. The selection of NF over other treatment technologies, however, is dependent on several factors including pretreatment requirements, influent water quality, treatment facility capacity, and treatment goals.

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