Mechanistic implications of plastic degradation

Recent trends in biodegradable polymers indicate significant developments in terms of novel design strategies and engineering to provide advanced polymers with comparably good performance. However, there are several inadequacies in terms of either technology or cost of production especially in the case of applications in environmental pollution. So, there is a need to have a fresh perspective on the design, properties and functions of these polymers with a view to developing strategies for future developments. The paper reviews the present state-of-art on biodegradable polymers and discusses the salient features of the design and properties of biodegradable polymers. Special emphasis is given to the problems and prospects of (1) approaches adopted to make non-biodegradable synthetic polymers such as polyethylene biodegradable and (2) biodegradable polymers and copolymers made from renewable resources especially poly(lactic acid) based polymers and copolymers which are emerging as the candidate biodegradable materials for the future.

Biodegradable Polymers- A Review on Recent Trends and Emerging Perspectives

https://digital.library.unt.edu/ark:/67531/metadc841162/m2/1/high_res_d/1004212.pdf

Biofuel alternatives to ethanol: pumping the microbial well

Sustainability of bio-based plastics: general comparative analysis and recommendations for improvement

The growing use of plastics in agriculture has enabled farmers to increase their crop production. One major drawback of most polymers used in agriculture is the problem with their disposal, following their useful life-time. Non-degradable polymers, being resistive to degradation (depending on the polymer, additives, conditions etc) tend to accumulate as plastic waste, creating a serious problem of plastic waste management. In cases such plastic waste ends-up in landfills or it is buried in soil, questions are raised about their possible effects on the environment, whether they biodegrade at all, and if they do, what is the rate of (bio?)degradation and what effect the products of (bio?)degradation have on the environment, including the effects of the additives used. Possible degradation of agricultural plastic waste should not result in contamination of the soil and pollution of the environment (including aesthetic pollution or problems with the agricultural products safety). Ideally, a degradable polymer should be fully biodegradable leaving no harmful substances in the environment. Most experts and acceptable standards define a fully biodegradable polymer as a polymer that is completely converted by microorganisms to carbon dioxide, water, mineral and biomass, with no negative environmental impact or ecotoxicity. However, part of the ongoing debate concerns the question of what is an acceptable period of time for the biodegradation to occur and how this is measured. Many polymers that are claimed to be ‘biodegradable’ are in fact ‘bioerodable’, ‘hydrobiodegradable’, ‘photodegradable’, controlled degradable or just partially biodegradable. This review paper attempts to delineate the definition of degradability of polymers used in agriculture. Emphasis is placed on the controversial issues regarding biodegradability of some of these polymers.

https://link.springer.com/content/pdf/10.1007%2Fs10924-007-0063-6.pdf

Biodegradation of Agricultural Plastic Films: A Critical Review

Plastic waste disposal is a huge ecotechnological problem and one of the approaches to solving this problem is the development of biodegradable plastics This review summarizes data on their use, biodegradability, commercial reliability and production from renewable resources Some commercially successful biodegradable plastics are based on chemical synthesis (ie polyglycolic acid, polylactic acid, polycaprolactone, and polyvinyl alcohol) Others are products of microbial fermentations (ie polyesters and neutral polysaccharides) or are prepared from chemically modified natural products (eg, starch, cellulose, chitin or soy protein)

Biodegradable plastics from renewable sources

Oligosaccharides produced by submerged cultures ofC. africana andC. sorghi were isolated by semipreparative HPLC. Structure of 6-O-β-d-fructofuranosyl-d-glucopyranose (blastose), 1,6-bis-O-(β-d-fructofuranosyl)-α-d-glucopyranoside (neokestose) and two sugar alcohols, 1-O-β-d-fructofuranosyl-d-mannitol (fructosylmannitol) and 1,6-bis-O-(β-d-fructofuranosyl)-d-mannitol (bisfructosylmannitol) was determined by NMR spectrometry. MALDI TOF MS analysis revealed molecular ions [M+Na]+ that indicate the presence of other tetra- and pentasaccharides (m/z=689.4 and 851.5, respectively) and corresponding sugar alcohol (m/z=691.4). Rapid conversion of sucrose into series of oligosaccharides and corresponding sugar alcohols was observed in all tested strains.

Oligosaccharides produced by submerged cultures of Claviceps africana and Claviceps sorghi.

Invasive pulmonary aspergillosis (IPA) may be a rare cause of granulomatous pneumonia in horses. The mortality of IPA is almost 100%; direct diagnostic tools in horses are needed. Bronchoalveolar lavage fluid (BALF) and serum samples were collected from 18 horses, including individuals suffering from IPA (n = 1), equine asthma (EA, n = 12), and 5 healthy controls. Serum samples were collected from another 6 healthy controls. Samples of BALF (n = 18) were analyzed for Aspergillus spp. DNA, fungal galactomannan (GM), ferricrocin (Fc), triacetylfusarinin C (TafC), and gliotoxin (Gtx). Analysis of 24 serum samples for (1,3)-β-D-glucan (BDG) and GM was performed. Median serum BDG levels were 131 pg/mL in controls and 1142 pg/mL in IPA. Similar trends were observed in BALF samples for GM (Area under the Curve (AUC) = 0.941) and DNA (AUC = 0.941). The fungal secondary metabolite Gtx was detected in IPA BALF and lung tissue samples (86 ng/mL and 2.17 ng/mg, AUC = 1).

/pdf/diagnosis-of-aspergillosis-in-horses-1syo1nkf.pdf

M. Kantorová

Papers

Biodegradable plastics from renewable sources

Oligosaccharides produced by submerged cultures of Claviceps africana and Claviceps sorghi.

Diagnosis of Aspergillosis in Horses