scholarly journals Duckweed: a model for phytoremediation technology

2021 ◽  
Vol 12 (1) ◽  
pp. 39-58
Author(s):  
Leela Kaur ◽  
Nupur Kanwar

The Lemnaceae or duckweed family comprises 37 species of smallest and simplest flowering plants. Duckweeds have a fast growth rate, can survive under a wide range of temperature and pH conditions and are easy to maintain and harvest which makes them an excellent candidate for bioremediation of wastewaters. The main objective of the present review is to extend an appreciation for the potential of living and non-living biomass of duckweed in remediating waters contaminated with heavy metals. Along with showing the detailed mechanism of phytoremediation by duckweed, the paper also discusses the enhancement of duckweed phytoremediation by the integration of transgenic technology. Furthermore, the paper explores other applications of duckweed specifically as fuel, animal feed, in human nutrition, in medicine and as a life support system. Apart from this, various disposal mechanisms for harvested duckweed have been analysed. Current understanding of removal efficiencies of several contaminants by employing duckweed is limited mainly to laboratory experiments. More concentrated and persistent efforts to develop efficient approaches for the genetic transformation of duckweeds can expand the development and utilization of duckweeds.

Author(s):  
David Vogel

This book examines the politics of consumer and environmental risk regulation in the United States and Europe over the last five decades, explaining why America and Europe have often regulated a wide range of similar risks differently. It finds that between 1960 and 1990, American health, safety, and environmental regulations were more stringent, risk averse, comprehensive, and innovative than those adopted in Europe. But since around 1990 global regulatory leadership has shifted to Europe. What explains this striking reversal? This book takes an in-depth, comparative look at European and American policies toward a range of consumer and environmental risks, including vehicle air pollution, ozone depletion, climate change, beef and milk hormones, genetically modified agriculture, antibiotics in animal feed, pesticides, cosmetic safety, and hazardous substances in electronic products. The book traces how concerns over such risks—and pressure on political leaders to do something about them—have risen among the European public but declined among Americans. The book explores how policymakers in Europe have grown supportive of more stringent regulations while those in the United States have become sharply polarized along partisan lines. And as European policymakers have grown more willing to regulate risks on precautionary grounds, increasingly skeptical American policymakers have called for higher levels of scientific certainty before imposing additional regulatory controls on business.


2020 ◽  
Vol 16 ◽  
Author(s):  
Diogo L. R. Novo ◽  
Priscila T. Scaglioni ◽  
Rodrigo M. Pereira ◽  
Filipe S. Rondan ◽  
Gilberto S. Coelho Junior ◽  
...  

Background: Conventional analytical methods for phosphorus and sulfur determination in several matrices present normally analytical challenges regarding inaccuracy, detectability and waste generation. Objective: The main objective is proposing a green and feasible analytical method for phosphorus and sulfur determination in animal feed. Methods: Synergic effect between microwave and ultraviolet radiations during sample preparation was evaluated for the first time for the animal feed digestion associated with further phosphorus and sulfur determination by ion chromatography with conductivity detection. Dissolved carbon and residual acidity in final digests were used for the proposed method assessment. Phosphorus and sulfur values were compared with those obtained using conventional microwave-assisted wet digestion in closed vessels associated with inductively coupled plasma optical emission spectrometry and with those obtained using Association of Official Analytical Chemists International official method. Recovery tests and certified reference material analysis were performed. Animal feeds were analyzed using the proposed method. Results: Sample masses of 500 mg were efficiently digested using only 2 mol L -1 HNO3. The results obtained by the proposed method was not differing significantly (p > 0.05) from those obtained by the conventional and official methods. Suitable recoveries (from 94 to 99%), agreement with certified values (101 and 104%) and relative standard deviations (< 8%) were achieved. Phosphorus and sulfur content in commercial products varied in a wide range (P: 5,873 to 28,387 mg kg-1 and S: 2,165 to 4,501 mg kg-1 ). Conclusion: The proposed method is a green, safe, accurate, precise and sensitive alternative for animal feed quality control.


2021 ◽  
Vol 15 (1) ◽  
Author(s):  
L. Osipova ◽  
O. Radionova ◽  
L. Tkachenko ◽  
T. Abramova

The analysis of the current state of processing of secondary raw materials of wine-making in Ukraine is given. It is proved that the latter is a rich source of biologically active compounds, including phenolic ones, which makes it possible to use it for the production of a wide range of products (raccoon, polyphenol extracts, tartaric acid, beverages, fertilizers, grape oil, cake, vitamin D, animal feed, food powder, abrasives) with high consumer value for various industries: food, pharmaceutical, perfume and cosmetics, chemical, feed, etc. In the light of modern research, the role of phenolic compounds as essential nutrition factors that cannot remain out of the field of view of physiologists, pharmacologists, and food hygiene specialists is shown. However, currently in Ukraine there are no specialized enterprises for complex processing of secondary raw materials of winemaking; traditional technologies are not effective from a technological, economic and environmental point of view, which indicates not rational use of resources and loss of material resources; there are no systematic studies on physical and chemical, microbiological, Toxicological composition in order to determine the optimal direction of its use. A limiting factor is also the lack of comparative analysis of innovative domestic and foreign technologies for processing secondary raw materials of winemaking. In the vast majority of cases, in particular, combs and pomace are taken out of control to agricultural land without special treatment, which leads to acid soil erosion and pollution of the environment with metabolites of micromycetes, increasing one of the global problems of mankind-environmental. At the present stage of technological development, there are a number of innovative developments in the field of processing secondary raw materials, in particular grape pomace, in order to obtain biologically active additives, the limiting factor for the introduction of which is the lack of domestic and expensive imported equipment. A promising way to solve the existing problems is to create a mechanism that will unite the interests of wineries (producers of secondary raw materials of winemaking), processing enterprises (producers of products from secondary raw materials of winemaking), scientists and potential consumers of innovative products. Consolidation of the above-mentioned institutions and enterprises is possible by creating clusters for the development and implementation of innovative technologies and equipment


Author(s):  
Ben Hadj-Daoud H ◽  
◽  
Ben Salem I ◽  
Boughalleb-M’Hamdi N ◽  
◽  
...  

Background: Colletotrichum gloeosporioides is important plant pathogens on a wide range of plant hosts such as citrus causing pre- or post-harvest infections as anthracnose, post-bloom fruit drop, tearstain and stem-end rot on fruit, or wither-tip of twigs. Method: The optimization of growth conditions of this pathogen was performed (solid media, temperature, pH and water potential under laboratory experiments). Results: Our results revealed that the maximum radial growth of C. gloeosporioides was recorded on SDA medium. All isolates were able to grow on PDA at temperatures of 15 and 30°C (over 0.7cm/day). Optimal growth radial was recorded at pH 5, 6, 7 and 8. Similar responses were obtained with both salt types, but, in general, C. gloeosporioides was more tolerant to KCl than NaCl. Conclusion: Studies of cultural, morphological traits of the pathogen are prominent to understand the response of the pathogen in different environmental and nutritional conditions.


2012 ◽  
Vol 1 (33) ◽  
pp. 50 ◽  
Author(s):  
Le Phuong Dong ◽  
Shinji Sato

Prototype scale laboratory experiments have been conducted to investigate the sheetflow sediment transport of uniform sands under different skewed-asymmetric oscillatory flows. Experimental results reveal that in most of the case with fine sand, the “cancelling effect”, which balances the on-/off-shore net transport under pure asymmetric/skewed flows and results a moderate net transport, was developed for combined skewed-asymmetric flow. However, under some certain conditions (T > 5s) with coarse sands, the onshore sediment transport was enhanced by 50% under combined skewed-asymmetric flows. Sand transport mechanism under oscillatory sheetflow conditions is also studied by comparing the maximum bed shear stress and the phase lag parameter at each half cycle. A comparison of measurements including the new experimental data with a number of practical sand transport formulations shows that the Dong et al. (2013) formulation performs the best in predicting the measured net transport rates over a wide range of experimental conditions


Author(s):  
Aneesa Dawood ◽  
Kesen Ma

Mannans are main components of hemicellulosic fraction of softwoods and they are present widely in plant tissues. β-mannanases are the major mannan-degrading enzymes and are produced by different plants, animals, actinomycetes, fungi, and bacteria. These enzymes can function under conditions of wide range of pH and temperature. Applications of β-mannanases have therefore, been found in different industries such as animal feed, food, biorefinery, textile, detergent, and paper and pulp. This review summarizes the most recent studies reported on potential applications of β-mannanases and bioengineering of β-mannanases to modify and optimize their key catalytic properties to cater to growing demands of commercial sectors.


Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xianzhe Meng

This paper introduces the basic principle and application process of simulated annealing algorithm and improves the simulated annealing algorithm so that it can converge faster to get the new parameters of cultural and creative product design and make it more in line with the reality of engineering optimization. In the cultural creative industry, it is necessary to use the creatorʼs creativity and technology to derive and develop the original cultural resources with the help of various materialization means, to refine the abstract and profound contents of cultural resources to make them more visualized, and to produce products with both spiritual and economic values through the multiple development and utilization of their intellectual property contents. By studying the feasibility analysis of the cultural and creative design, the design positioning of the cultural and creative products is determined. In this article, we use the simulated annealing method to simulate and analyse the condition values in the design process of cultural creative products. As the Internet era progresses, people have more diversified requirements for cultural and creative products, and they need to have innovative ideas to follow the trend, so the design of cultural and creative products can spread culture through different design expressions and media. As one of the important pillar industries for future development, cultural and creative products are characterized by a wide range of styles and practicality, which meet the aesthetic needs and fashion trends of modern people.


2021 ◽  
Vol 15 (2) ◽  
Author(s):  
L. Osipova ◽  
A. Khodakov ◽  
O. Radionova ◽  
L. Tkachenko ◽  
T. Abramova

The current state of processing secondary raw materials of winemaking in Ukraine has been analysed. It has been shown that these materials are a rich source of bioactive compounds. This allows using them to manufacture a wide range of products (oenological tannin, food oenocolourant, polyphenolic extracts, tartaric acid, beverages, grape oil, vitamin D, protein, animal feed, food powder, fertilisers, abrasive materials, etc.) with high consumer value for various industries: food, pharmaceutical, perfume and cosmetics, chemical, compound feed, etc. In the light of modern views, phenolic compounds contained in large quantities in grape stems and pomace have been shown to be indispensable factors in nutrition and treatment. It has been noted that in today’s Ukraine, there are no specialised enterprises for complex processing of secondary raw materials of winemaking. In particular, unprocessed grape stalks and pomace are in most cases uncontrollably carried away to farmlands. This leads to acid erosion of the soil and to polluting the environment by micromycete metabolites, which but exacerbates one of mankind’s global problems, the environmental one. It has been concluded that traditional domestic technologies of processing secondary raw materials of winemaking are technologically, economically, and environmentally ineffective. There is no comparative analysis of innovative domestic and foreign technologies and equipment for processing secondary raw materials of winemaking. Modern innovations to obtain bioactive additives and other products cannot be introduced, since there is no necessary home-manufactured equipment, and imported machines are too expensive. Besides, there is but weak interaction among wineries, research institutions, business structures, and administrative authority. Cluster ideology has been suggested as a basis to organise comprehensive processing of secondary raw materials of winemaking in Ukraine. This will unite the interests of wineries (producers of secondary raw materials), processing enterprises (manufacturers of products from secondary raw materials), research institutions, and potential consumers of innovative products


1973 ◽  
Vol 63 (1) ◽  
pp. 7-16 ◽  
Author(s):  
I. Gelbič ◽  
F. Sehnal

AbstractLaboratory experiments with juvenile hormone analogues on Cydia pomonella (L.) showed that Cecropia C17 juvenile hormone (methyl 10,ll-epoxy-3,7,ll-trimethyl-2,6-dodecadienoate) was the most active of the 28 compounds tested. When applied to four-hour-old eggs at 0.1 μg/egg, the hormone caused 100% failure in embryogenesis, while the other compounds were at least five times less effective. Depending on the time since ecdysis and the dose, juvenile hormone mimics applied to last-instar larvae resulted in a wide range of intermediate forms. Against three-day-old last-instar larvae, the Cecropia C17 hormone gave 100% inhibition of development at a dose of 1 μg/larva, while three other compounds (methyl 10,11-epoxy-3,7,11-trimethyl-2,6-dodecadienoate, ethyl 11-chloro-3,7,11-trimethyl-2-dodecenoate and ethyl 3,7,11-tri-methyl-2,4-dodecadienoate) gave the same effect at 2–5 μg/larva. Against newly emerged adults, the last two compounds at 10–50 μg/insect reduced fecundity and fertility to 0–81% and 0–50%, respectively, of their normal levels.


Author(s):  
Jeffrey S. Oishi ◽  
Geoffrey M. Vasil ◽  
Morgan Baxter ◽  
Andrew Swan ◽  
Keaton J. Burns ◽  
...  

The magnetorotational instability (MRI) occurs when a weak magnetic field destabilizes a rotating, electrically conducting fluid with inwardly increasing angular velocity. The MRI is essential to astrophysical disc theory where the shear is typically Keplerian. Internal shear layers in stars may also be MRI-unstable, and they take a wide range of profiles, including near-critical. We show that the fastest growing modes of an ideal magnetofluid are three-dimensional provided the shear rate, S , is near the two-dimensional onset value, S c . For a Keplerian shear, three-dimensional modes are unstable above S  ≈ 0.10 S c , and dominate the two-dimensional modes until S  ≈ 2.05 S c . These three-dimensional modes dominate for shear profiles relevant to stars and at magnetic Prandtl numbers relevant to liquid-metal laboratory experiments. Significant numbers of rapidly growing three-dimensional modes remainy well past 2.05 S c . These finding are significant in three ways. First, weakly nonlinear theory suggests that the MRI saturates by pushing the shear rate to its critical value. This can happen for systems, such as stars and laboratory experiments, that can rearrange their angular velocity profiles. Second, the non-normal character and large transient growth of MRI modes should be important whenever three-dimensionality exists. Finally, three-dimensional growth suggests direct dynamo action driven from the linear instability.


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