Degradability of Polyurethanes and Their Blends with Polylactide, Chitosan and Starch

One of the methods of making traditional polymers more environmentally friendly is to modify them with natural materials or their biodegradable, synthetic equivalents. It was assumed that blends with polylactide (PLA), polysaccharides: chitosan (Ch) and starch (St) of branched polyurethane (PUR) based on synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) would degrade faster in the processes of hydrolysis and oxidation than pure PUR. For the sake of simplicity in the publication, all three modifiers: commercial PLA, Ch created by chemical modification of chitin and St are called bioadditives. The samples were incubated in a hydrolytic and oxidizing environment for 36 weeks and 11 weeks, respectively. The degradation process was assessed by observation of the chemical structure as well as the change in the mass of the samples, their molecular weight, surface morphology and thermal properties. It was found that the PUR samples with the highest amount of R,S-PHB and the lowest amount of polycaprolactone triol (PCLtriol) were degraded the most. Moreover, blending with St had the greatest impact on the susceptibility to degradation of PUR. However, the rate of weight loss of the samples was low, and after 36 weeks of incubation in the hydrolytic solution, it did not exceed 7% by weight. The weight loss of Ch and PLA blends was even smaller. However, a significant reduction in molecular weight, changes in morphology and changes in thermal properties indicated that the degradation of the samples should occur quickly after this time. Therefore, when using these polyurethanes and their blends, it should be taken into account that they should decompose slowly in their initial life. In summary, this process can be modified by changing the amount of R,S-PHB, the degree of cross-linking, and the type and amount of second blend component added (bioadditives).This research was founded by the National Science Center Poland Miniatura 2 project no. 2018/02/X/ST5/02005 and partially by the UMG research project no. WZNJ/2021/PZ/02

Properties of poly(acrylic acid)/modified starch compositions applied as a new polymeric binders

Zbadano stabilność wybranych właściwości fizykochemicznych nowych, ekologicznych spoiw polimerowych w postaci wodorozcieńczalnych kompozycji poli(kwas akrylowy)/sól sodowa karboksymetyloskrobi (PAA/CMS-Na). Wodną kompozycję PAA/CMS-Na przechowywano w zamkniętych naczyniach w temp. 10 °C. Podczas trzymiesięcznego przechowywania badano zmiany zabarwienia, lepkości, kąta zwilżania szkła kwarcowego, struktury oraz rozkładu wymiarów cząstek spoiwa i na tej podstawie dokonano wstępnej oceny stabilności kompozycji. Sporządzono i utwardzono masy formierskie z udziałem wodnej kompozycji PAA/CMS-Na i określono ich wytrzymałość na zginanie. Stwierdzono, że w założonym czasie przechowywania, w warunkach zbliżonych do panujących w odlewni, nowe spoiwo nie traci właściwości wiążących ziarna piasku osnowy w masie formierskiej.The selected physicochemical properties of water-thinnable poly(acrylic acid)/sodiumsalt of carboxymethyl starch (PAA/CMS-Na) compositions — new environmentally friendly polymer binding agents — were investigated as a function of time. The aqueous composition PAA/CMS-Na was stored in closed vessels in a cooling chamber at 10 °C. During the three-month storage period the changes of coloration, viscosity, wetting angle on quartz glass, structure and size distribution of the binding agent particles were studied. On this basis, the stability of the binder properties was preliminarily evaluated. Additionally, the moulding sands containing an aqueous composition PAA/CMS-Naas a binder (stored for a week or three months) were prepared, hardened and subjected to the bending strength tests. It was found, that after three months of storage under conditions resembling those found in a foundry the new binder did not lose its properties as a binding agent for the moulding sand

Poly-Gamma-Glutamic Acid (γ-PGA)-based encapsulation of Adenovirus to evade neutralizing antibodies.

In recent years, there has been an increasing interest in oncolytic adenoviral vectors as an alternative anticancer therapy. The induction of an immune response can be considered as a major limitation of this kind of application. Significant research efforts have been focused on the development of biodegradable polymer poly-gamma-glutamic acid (γ-PGA)-based nanoparticles used as a vector for effective and safe anticancer therapy, owing to their controlled and sustained-release properties, low toxicity, as well as biocompatibility with tissue and cells. This study aimed to introduce a specific destructive and antibody blind polymer-coated viral vector into cancer cells using γ-PGA and chitosan (CH). Adenovirus was successfully encapsulated into the biopolymer particles with an encapsulation efficiency of 92% and particle size of 485 nm using the ionic gelation method. Therapeutic agents or nanoparticles (NPs) that carry therapeutics can be directed specifically to cancerous cells by decorating their surfaces using targeting ligands. Moreover, in vitro neutralizing antibody response against viral capsid proteins can be somewhat reduced by encapsulating adenovirus into γ-PGA-CH NPs, as only 3.1% of the encapsulated adenovirus was detected by anti-adenovirus antibodies in the presented work compared to naked adenoviruses. The results obtained and the unique characteristics of the polymer established in this research could provide a reference for the coating and controlled release of viral vectors used in anticancer therapy.This work was funded by the Ministry of Higher Education and Scientific Research (Iraq). This work was also partially funded by the Research Investment Fund, University of Wolverhampton (Wolverhampton, United Kingdom) and the Italian Ministry of University and Research (MIUR)

Building a circular economy around poly(D/L-γ-glutamic acid)- a smart microbial biopolymer

© 2022 The Authors. Published by Elsevier. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1016/j.biotechadv.2022.108049Bio-derived materials have long been harnessed for their potential as backbones of biodegradable constructs. With increasing understanding of organismal biochemistry and molecular genetics, scientists are now able to obtain biomaterials with properties comparable to those achieved by the petroleum industry. Poly-γ-glutamic acid (γ-PGA) is an anionic pseudopolypeptide produced and secreted by several microorganisms, especially Bacillus species. γ-PGA is polymerised via the pgs intermembrane enzymatic complex expressed by many bacteria (including GRAS member - Bacillus subtilis). γ-PGA can exist as a homopolymer of L- glutamic acid or D- glutamic acid units or it can be a co-polymer comprised of D and L enantiomers. This non-toxic polymer is highly viscous, soluble, biodegradable and biocompatible. γ-PGA is also an example of versatile chiral-polymer, a characteristic that draws great attention from the industry. Increased understanding in the correlation between microbial genetics, substrate compositions, fermentation conditions and polymeric chemical characteristics have led to bioprocess optimisation to provide cost competitive, non-petroleum-based, biodegradable solutions. This review presents detailed insights into microbial synthesis of γ-PGA and summaries current understanding of the correlation between genetic makeup of γ-PGA-producing bacteria, range of culture cultivation conditions, and physicochemical properties of this incredibly versatile biopolymer. Additionally, we hope that review provides an updated overview of findings relevant to sustainable and cost-effective biosynthesis of γ-PGA, with application in medicine, pharmacy, cosmetics, food, agriculture and for bioremediation.This work was partially supported the University of Wolverhampton Research Investment Fund (RIF4); ERDF Science in Industry Research Centre (SIRC 01R19P03464) project and BBSRC Algae-UK for Proof of Concept project BB/S009825/1; UCL Ref: 5749484.Published versio

The microbial production of polyhydroxyalkanoates from waste polystyrene fragments attained using oxidative degradation

© 2018 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/polym10090957Excessive levels of plastic waste in our oceans and landfills indicate that there is an abundance of potential carbon sources with huge economic value being neglected. These waste plastics, through biological fermentation, could offer alternatives to traditional petrol-based plastics. Polyhydroxyalkanoates (PHAs) are a group of plastics produced by some strains of bacteria that could be part of a new generation of polyester materials that are biodegradable, biocompatible, and, most importantly, non-toxic if discarded. This study introduces the use of prodegraded high impact and general polystyrene (PS0). Polystyrene is commonly used in disposable cutlery, CD cases, trays, and packaging. Despite these applications, some forms of polystyrene PS remain financially and environmentally expensive to send to landfills. The prodegraded PS0 waste plastics used were broken down at varied high temperatures while exposed to ozone. These variables produced PS flakes (PS1–3) and a powder (PS4) with individual acid numbers. Consequently, after fermentation, different PHAs and amounts of biomass were produced. The bacterial strain, Cupriavidus necator H16, was selected for this study due to its well-documented genetic profile, stability, robustness, and ability to produce PHAs at relatively low temperatures. The accumulation of PHAs varied from 39% for prodegraded PS0 in nitrogen rich media to 48% (w/w) of dry biomass with the treated PS. The polymers extracted from biomass were analyzed using nuclear magnetic resonance (NMR) and electrospray ionization tandem mass spectrometry (ESI-MS/MS) to assess their molecular structure and properties. In conclusion, the PS0–3 specimens were shown to be the most promising carbon sources for PHA biosynthesis; with 3-hydroxybutyrate and up to 12 mol % of 3-hydroxyvalerate and 3-hydroxyhexanoate co-monomeric units generated

Nanolayers of Poly(N,N’-Dimethylaminoethyl Methacrylate) with a Star Topology and Their Antibacterial Activity

In this paper, we focus on the synthesis and characterization of novel stable nanolayers made of star methacrylate polymers. The e ect of nanolayer modification on its antibacterial properties was also studied. A covalent immobilization of star poly(N,N0-dimethylaminoethyl methacrylate) (PDMAEMA) to benzophenone functionalized glass or silicon supports was carried out via a “grafting to” approach using UV irradiation. To date, star polymer UV immobilization has never been used for this purpose. The thickness of the resulting nanolayers increased from 30 to 120 nm with the molar mass of the immobilized stars. The successful bonding of star PDMAEMA to the supports was confirmed by surface sensitive quantitative spectroscopic methods. Next, amino groups in the polymer layer were quaternized with bromoethane, and the influence of this modification on the antibacterial properties of the obtained materials was analyzed using a selected reference strain of bacteria. The resulting star nanolayer surfaces exhibited higher antimicrobial activity against Bacillus subtilis ATCC 6633 compared to that of the linear PDMAEMA analogues grafted onto a support. These promising results and the knowledge about the influence of the topology and modification of PDMAEMA layers on their properties may help in searching for new materials for antimicrobial applications in medicine

A circular bioprocess application of algal-based substrate for Bacillus subtilis natto production of γ-PGA

© 2023 The Authors. Published by Frontiers Media. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3389/fchem.2023.1158147Poly-γ-glutamic acid (γ-PGA) is a bio-derived water-soluble, edible, hydrating, non-immunogenic polymer. Bacillus subtilis natto is a wild-type γ-PGA producer originally isolated from Japanese fermented natto beans whose activity has been shown to be enhanced through ion-specific activation of Extrachromosomal DNA maintenance mechanisms. Being a GRAS γ-PGA producer, this microorganism has attracted great interest in its use within an industrial context. Here we successfully synthesised amorphous, crystalline and semi-crystalline γ-PGA between 11–27 g/L. In line with circular economy principles, scalable macroalgal biomass has been evaluated as substrate for γ-PGA, displaying great potential in both yields and material composition. In this study whole cell, freeze dried seaweed -namely Laminaria digitata, Saccharina latissima and Alaria esculenta-were pre-treated by means of mechanical methods, sterilised and subsequently inoculated with B. subtilis natto. High shear mixing was found to be the most suitable pre-treatment technique. Supplemented L. digitata (9.1 g/L), S. latissima (10.2 g/L), A. esculenta (13 g/L) displayed γ-PGA yields comparable to those of standard GS media (14.4 g/L). Greatest yields of pure γ-PGA were obtained during the month of June for L. digitata (Avg. 4.76 g/L) comparable to those obtained with GS media (7.0 g/L). Further, pre-treated S. latissima and L. digitata complex media enabled for high molar mass (4,500 kDa) γ-PGA biosynthesis at 8.6 and 8.7 g/L respectively. Compared to standard GS media, algal derived γ-PGA displayed significantly higher molar masses. Further studies will be necessary to further evaluate the impact of varying ash contents upon the stereochemical properties and modify the properties of algal media based γ-PGA with the aid of key nutrients; however, the material synthesised to date can directly displace a number of fossil fuel derived chemicals in drug delivery applications, cosmetics, bioremediation, wastewater treatment, flocculation and as cryoprotectants.This work was partially supported the University of Wolverhampton Research Investment Fund (RIF4); ERDF Science in Industry Research Centre (SIRC 01R19P03464) project, BBSRC Algae-UK for Proof of Concept project BB/S009825/1; UCL Ref: 5749484, partially funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 872152, project GREEN-MAP and co-financed by the program of the Polish Minister of Science and Higher Education entitled “PMW” in the years 2020–2023; contract No 5092/H2020/2020/2 and European Union’s Horizon 2020 research and innovation programme under grant agreement No 774109 (project “Intelligent Management System for Integrated Multi-trophic Aquaculture—IMPAQT”)

Mass spectrometry reveals molecular structure of polyhydroxyalkanoates attained by bioconversion of oxidized polypropylene waste fragments

This study investigated the molecular structure of the polyhydroxyalkanoate (PHA) produced via a microbiological shake flask experiment utilizing oxidized polypropylene (PP) waste as an additional carbon source. The bacterial strain Cupriavidus necator H16 was selected as it is non-pathogenic, genetically stable, robust, and one of the best known producers of PHA. Making use of PHA oligomers, formed by controlled moderate-temperature degradation induced by carboxylate moieties, by examination of both the parent and fragmentation ions, the ESI-MS/MS analysis revealed the 3-hydroxybutyrate and randomly distributed 3-hydroxyvalerate as well as 3-hydroxyhexanoate repeat units. Thus, the bioconversion of PP solid waste to a value-added product such as PHA tert-polymer was demonstrated.This research was funded by the Research Investment Fund, University of Wolverhampton, Faculty of Science and Engineering, UK. This work was also partially supported the European Regional Development Fund Project EnTRESS No 01R16P00718 and the PELARGODONT Project UM0-2016/22/Z/STS/00692 financed under the M-ERA.NET 2 Program of Horizon 2020.Published onlin

The effect of biologically and chemically synthesized silver nanoparticles (AgNPs) on biofilm formation

Bionanotechnology has emerged up as integration between biotechnology and nanotechnology for developing biosynthetic and environmental-friendly technology for synthesis of nanomaterials. Different types of nanomaterials like copper, zinc, titanium, magnesium, gold, and silver have applied in the various industries but silver nanoparticles have proved to be most effective against bacteria, viruses and eukaryotic microorganisms. The antimicrobial property of silver nanoparticles are widely known. Due to strong antibacterial property silver nanoparticles are used, e.g. in clothing, food industry, sunscreens, cosmetics and many household and environmental appliances. The aim of the study was to compare the effect of silver nanoparticles (AgNPs) synthesized biologically and chemically on the biofilm formation. The biofilm was formed by the bacteria isolated from the water supply network. The commonly used crystal violet assay (CV) was applied for biofilm analysis. In this study effect of biologically synthesized Ag-NPs on the biofilm formation was evaluated

The effect of biologically and chemically synthesized silver nanoparticles (AgNPs) on biofilm formation

Bionanotechnology has emerged up as integration between biotechnology and nanotechnology for developing biosynthetic and environmental-friendly technology for synthesis of nanomaterials. Different types of nanomaterials like copper, zinc, titanium, magnesium, gold, and silver have applied in the various industries but silver nanoparticles have proved to be most effective against bacteria, viruses and eukaryotic microorganisms. The antimicrobial property of silver nanoparticles are widely known. Due to strong antibacterial property silver nanoparticles are used, e.g. in clothing, food industry, sunscreens, cosmetics and many household and environmental appliances. The aim of the study was to compare the effect of silver nanoparticles (AgNPs) synthesized biologically and chemically on the biofilm formation. The biofilm was formed by the bacteria isolated from the water supply network. The commonly used crystal violet assay (CV) was applied for biofilm analysis. In this study effect of biologically synthesized Ag-NPs on the biofilm formation was evaluated