Lignin peroxidase isoenzyme: a novel approach to biodegrade the toxic synthetic polymer waste

The utilization of single-use polymer increases day by day and there is no alternative to resolve the problem of waste management till now. It is estimated that 1.1 to 8.8 million tonnes of polymer waste enters the ocean from coastal communities each year. Recent researches suggest that there could be more synthetic polymer than fish in the oceans by weight by the year 2050. White pollution (polymer pollution) has build up an island in between the pacific ocean according to recent studies. This accumulation of polymer waste can face a huge negative imact on both aquatic and terrestial ecosystems. One recent study also shown that polymer pollution can cause cancer in humans. To overcome this problem, there is a requirement to think of another way to introduce a product which has a resemblance with synthetic polymer and has a feature that makes it degradable and economic. Various biopolymer are synthesized by microorganisms that could able to replace the synthetic one. The advantage of using a biopolymer is that it can be biodegradable, could manage the agricultural plant waste as well as environmental waste which is directly responsible for pollution. To fulfill the demand, various biopolymer have been designed all over the world. This review concludes various example of Biopolymer Films with analysis for effective suggestions against Polymer Pollution (White Pollution).

Download Full-text

Thermochemical, kinetic and ash characteristics behaviour of Thar Lignite, agricultural residues and synthetic polymer waste (EVA)

Fuel ◽

10.1016/j.fuel.2020.117151 ◽

2020 ◽

Vol 266 ◽

pp. 117151 ◽

Cited By ~ 4

Author(s):

Abdul Wahab ◽

Hamed Sattar ◽

Asma Ashraf ◽

Syed Nadir Hussain ◽

Mahmood Saleem ◽

...

Keyword(s):

Synthetic Polymer ◽

Agricultural Residues ◽

Polymer Waste

Download Full-text

Criteria for the Selection of Synthetic Polymeric Waste as a Raw Material for Producing Carbon Sorbents with Predetermined Properties

Ecology and Industry of Russia ◽

10.18412/1816-0395-2020-10-13-19 ◽

2020 ◽

Vol 24 (10) ◽

pp. 13-19

Author(s):

Ya.I. Vaisman ◽

I.S. Glushankova ◽

L.V. Rudakova ◽

A.A. Surkov ◽

A.S. Atanova

Keyword(s):

Raw Materials ◽

Synthetic Polymer ◽

Raw Material ◽

Technological Parameters ◽

Polymer Waste ◽

Factors Affecting ◽

Carbon Sorbents ◽

Degree Of Aromaticity ◽

Polymeric Waste ◽

Selection Of

The results of studies on the thermal processing of synthetic multi-tonnage polymeric waste (polypropylene, polycarbonate, textolite, PET, organoplastics and tire rubber) with the production of carbon sorbents for technological and environmental purposes are presented. The influence of the nature of the activating agent and the conditions of the process with the production of sorbents with predetermined properties was studied. Analysis of the research results allowed us to establish that the main factors affecting the yield of carbonizate and the formation of a porous structure of carbon sorbents from synthetic polymer waste are the degree of aromaticity and the location of benzene rings in the polymer structure, the proportion of oxygen in the precursor. The criteria for selecting synthetic polymer wastes as raw materials for obtaining carbon sorbents with predetermined properties are established. The results of the research can be used in the development of technologies for obtaining carbon sorbents with predetermined properties from waste synthetic polymers and the selection of technological parameters for processes.

Download Full-text

Reversible alkaline inactivation of lignin peroxidase involves the release of both the distal and proximal site calcium ions and bishistidine co-ordination of the haem

Biochemical Journal ◽

10.1042/bj3440237 ◽

1999 ◽

Vol 344 (1) ◽

pp. 237-244 ◽

Cited By ~ 21

Author(s):

Simon J. GEORGE ◽

Mamuka KVARATSKHELIA ◽

Michael J. DILWORTH ◽

Roger N. F. THORNELEY

Keyword(s):

Calcium Ions ◽

Lignin Peroxidase ◽

Room Temperature ◽

Epr Spectrum ◽

Peroxidase Isoenzyme ◽

Near Ir ◽

Peak Intensity ◽

Inactive Form ◽

Proximal Site ◽

Spectroscopic Characteristics

Phanerochaete chrysosporium lignin peroxidase isoenzyme H2 (LiP H2) exhibits a transition to a stable, inactive form at pH 9.0 with concomitant spectroscopic changes. The Söret peak intensity decreases some 55% with a red shift from 408 to 412 nm; the bands at 502 nm and 638 nm disappear and the peak at 536 nm increases. The EPR spectrum changes from a signal typical of high spin ferric haem to an exclusively low spin spectrum with g = 2.92, 2.27, 1.50. These data indicate that the active pentaco-ordinated haem is converted into a hexaco-ordinated species at alkaline pH. Room temperature near-IR MCD data coupled with the EPR spectrum allow us to assign the haem co-ordination of alkali-inactivated enzyme as bishistidine. Re-acidification of the alkali-inactivated enzyme to pH 6 induces further spectroscopic changes and generates an irreversibly inactivated species. By contrast, a pH shift from 9.0 to 6.0 with simultaneous addition of 50 mM CaCl2 results in the recovery of the initial activity together with the spectroscopic characteristics of the native ferric enzyme. Incubating with 50 mM CaCl2 at a pH between 6.0 and 9.0 can also re-activate the enzyme. Divalent metals other than Ca2+ do not result in restoration of activity. Experiments with 45Ca indicate that two tightly bound calcium ions per enzyme monomer are lost during inactivation and reincorporated during subsequent re-activation, consistent with the presence of two structural Ca2+ ions in LiP H2. It is concluded that both the structural Ca2+ ions play key roles in the reversible alkaline inactivation of LiP H2.

Download Full-text

Comparative Analysis of Fuels Derived from PE Plastic Waste with a Mixture of Plastic Recycling Waste of Codes: 1, 2, 4, 5, 6 and 7 Based on Low-Temperature Pyrolysis

Journal of KONES ◽

10.2478/kones-2019-0102 ◽

2019 ◽

Vol 26 (4) ◽

pp. 149-154

Author(s):

Anna Lesnau ◽

Mirosław Tyliszczak

Keyword(s):

Low Temperature ◽

Waste Treatment ◽

Plastic Material ◽

Petroleum Products ◽

High Energy ◽

Synthetic Polymer ◽

High Energy Density ◽

Alternative Methods ◽

Polymer Waste ◽

Low Temperature Pyrolysis

AbstractThanks to their numerous advantages, plastics are becoming more and more widely used in all branches of industry. The quantities of products, their packaging and, consequently, the amount of synthetic polymer waste are steadily increasing, what poses a high risk to the environment due to their long decomposition time. To reduce waste production is practically impossible, therefore it is very important to constantly implement new and improve existing methods of waste treatment. The following article presents one of the alternative methods for synthetic polymer waste treatment, which is low-temperature pyrolysis. Two pyrolysis processes were carried out. During the first experiment a polyethylene plastic material was used, in the second experiment a mixture of typical household recycling waste of codes 1, 2, 4, 5, 6, and 7 were tested. During the thermal processing, the input material undergoes a chemical transformation due to breaking of long hydrocarbon chains. At the same time, high-energy density products, such as petroleum products and gas, are produced. The main advantage of the presented method is that it allows reducing preliminary technological processes to a minimum and it is easily automated, as it reduces the process to one compact installation. The reduction of the amount of stored waste and the recovery of petroleum derivatives, are additional advantages of pyrolysis implementation. That, in consequence allows reducing consumption of fossil fuel resources.

Download Full-text

Electron-diffraction studies in synthetic polymer materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075579 ◽

1983 ◽

Vol 41 ◽

pp. 362-365

Author(s):

D.T. Grubb

Keyword(s):

Electron Diffraction ◽

Synthetic Polymer ◽

Polymer Materials ◽

Crystallographic Structure ◽

High Dose ◽

Electron Dose ◽

Dose Rates ◽

First Case ◽

Diffraction Patterns ◽

The Many

Diffraction studies in polymeric and other beam sensitive materials may bring to mind the many experiments where diffracted intensity has been used as a measure of the electron dose required to destroy fine structure in the TEM. But this paper is concerned with a range of cases where the diffraction pattern itself contains the important information.In the first case, electron diffraction from paraffins, degraded polyethylene and polyethylene single crystals, all the samples are highly ordered, and their crystallographic structure is well known. The diffraction patterns fade on irradiation and may also change considerably in a-spacing, increasing the unit cell volume on irradiation. The effect is large and continuous far C94H190 paraffin and for PE, while for shorter chains to C 28H58 the change is less, levelling off at high dose, Fig.l. It is also found that the change in a-spacing increases at higher dose rates and at higher irradiation temperatures.

Download Full-text

Copper-dependent ATP7B up-regulation drives the resistance of TMEM16A-overexpressing head-and-neck cancer models to platinum toxicity

Biochemical Journal ◽

10.1042/bcj20190591 ◽

2019 ◽

Vol 476 (24) ◽

pp. 3705-3719 ◽

Cited By ~ 2

Author(s):

Avani Vyas ◽

Umamaheswar Duvvuri ◽

Kirill Kiselyov

Keyword(s):

Oxidative Stress ◽

Head And Neck ◽

Transcriptional Activation ◽

Platinum Resistance ◽

Mrna Levels ◽

Strong Positive Correlation ◽

Platinum Compounds ◽

Copper Chelation ◽

Novel Approach ◽

Cancer Models

Platinum-containing drugs such as cisplatin and carboplatin are routinely used for the treatment of many solid tumors including squamous cell carcinoma of the head and neck (SCCHN). However, SCCHN resistance to platinum compounds is well documented. The resistance to platinum has been linked to the activity of divalent transporter ATP7B, which pumps platinum from the cytoplasm into lysosomes, decreasing its concentration in the cytoplasm. Several cancer models show increased expression of ATP7B; however, the reason for such an increase is not known. Here we show a strong positive correlation between mRNA levels of TMEM16A and ATP7B in human SCCHN tumors. TMEM16A overexpression and depletion in SCCHN cell lines caused parallel changes in the ATP7B mRNA levels. The ATP7B increase in TMEM16A-overexpressing cells was reversed by suppression of NADPH oxidase 2 (NOX2), by the antioxidant N-Acetyl-Cysteine (NAC) and by copper chelation using cuprizone and bathocuproine sulphonate (BCS). Pretreatment with either chelator significantly increased cisplatin's sensitivity, particularly in the context of TMEM16A overexpression. We propose that increased oxidative stress in TMEM16A-overexpressing cells liberates the chelated copper in the cytoplasm, leading to the transcriptional activation of ATP7B expression. This, in turn, decreases the efficacy of platinum compounds by promoting their vesicular sequestration. We think that such a new explanation of the mechanism of SCCHN tumors’ platinum resistance identifies novel approach to treating these tumors.

Download Full-text

Collecting Words: A Clinical Example of a Morphology-Focused Orthographic Intervention

Language Speech and Hearing Services in Schools ◽

10.1044/2020_lshss-19-00050 ◽

2020 ◽

Vol 51 (3) ◽

pp. 544-560 ◽

Cited By ~ 3

Author(s):

Kimberly A. Murphy ◽

Emily A. Diehm

Keyword(s):

Written Language ◽

Morphological Knowledge ◽

English Orthography ◽

Word Level ◽

Novel Approach ◽

Language Pathology ◽

The One ◽

Critical Intervention ◽

Reading And Spelling ◽

Reading And Spelling Difficulties

Purpose Morphological interventions promote gains in morphological knowledge and in other oral and written language skills (e.g., phonological awareness, vocabulary, reading, and spelling), yet we have a limited understanding of critical intervention features. In this clinical focus article, we describe a relatively novel approach to teaching morphology that considers its role as the key organizing principle of English orthography. We also present a clinical example of such an intervention delivered during a summer camp at a university speech and hearing clinic. Method Graduate speech-language pathology students provided a 6-week morphology-focused orthographic intervention to children in first through fourth grade ( n = 10) who demonstrated word-level reading and spelling difficulties. The intervention focused children's attention on morphological families, teaching how morphology is interrelated with phonology and etymology in English orthography. Results Comparing pre- and posttest scores, children demonstrated improvement in reading and/or spelling abilities, with the largest gains observed in spelling affixes within polymorphemic words. Children and their caregivers reacted positively to the intervention. Therefore, data from the camp offer preliminary support for teaching morphology within the context of written words, and the intervention appears to be a feasible approach for simultaneously increasing morphological knowledge, reading, and spelling. Conclusion Children with word-level reading and spelling difficulties may benefit from a morphology-focused orthographic intervention, such as the one described here. Research on the approach is warranted, and clinicians are encouraged to explore its possible effectiveness in their practice. Supplemental Material https://doi.org/10.23641/asha.12290687

Download Full-text