Agnieszka Richert

• PhD
• Research Assistant at Nicolaus Copernicus University

The purpose of this study was to assess the ability of Bacillus aryabhattai RAF 5 to produce P(3HB) under conditions of periodic medium renewal (PMR). The producer was isolated and confirmed using transmission electron microscopy (TEM), which revealed the presence of more than 10 dense P(3HB) granules per cell. The purity of the isolated polymer wa...

In this article, we present polymer materials consisting of polylactide (PLA) and nisaplin (N), as well as PLA and natamax (X). These materials were obtained using the solvent method and tested by various test methods, i.e., functional properties—water vapor permeability, light transmission, gloss, and bactericidal activity against strains E. coli...

We present new polymer materials consisting of polycaprolactone (PCL), polyethylene glycol (PEG), and birch tar (D). PEG was introduced into the polymer matrix in order to obtain a plasticizing effect, while tar was added to obtain antibacterial properties and to change the physicochemical properties of the film. The materials were obtained by the...

The aim of the study was to determine the potential use of fungi of the genus Trichoderma for the degradation of phenolic acid-modified chitosan in compost. At the same time, the enzymatic activity in the compost was checked after the application of a preparation containing a suspension of the fungi Trichoderma (spores concentration 105/mL). The Tr...

A series of biopolymeric chitosan-based (Ch) films were prepared with choline chloride and citric acid plasticizer (deep eutectic solvent, DES). An effect of adenine (A, vitamin B4) addition on the functional properties of these films was evaluated. Several physicochemical and mechanical properties were tested: Fourier-transformed infrared spectra...

The plasticized film was made of polylactide and birch tar, which was used in a concentration of 1, 5 and 10 % by weight. Tar was added to the polymer to obtain materials with antimicrobial properties. The main purpose of this work is to characterize and biodegradation of this film after the end of its use. Therefore, the following analyzes were pe...

The aim of the study was to evaluate possibility of producing a polylactide film with birch tar by the industrial extrusion method and whether the addition of 10% birch tar can ensure adequate biocidal properties of PLA against pathogenic microorganisms (E. coli, S. aureus, P. aeruginosa, A. tumefaciens, X. campestris, P. brassicacearum, P. corruga...

Serratia plymuthica strain IV-11-34 belongs to the plant growth promoting bacteria (PGPR). In the sequenced genome of S. plymuthica IV-11-34, we have identified the genes involved in biodegradation and metabolisms of xenobiotics. The potential of S. plymuthica IV-11-34 for the degradation of biodegradable aliphatic polyester polylactide (PLA) and r...

The microbial biodegradation of new PLA and PCL materials containing birch tar (1–10% v/v) was investigated. Product of dry distillation of birch bark (Betula pendula Roth) was added to polymeric materials to obtain films with antimicrobial properties. The subject of the study was the course of enzymatic degradation of a biodegradable polymer with...

Agnieszka Richert1, Justine Gaurenne2, Guillaume Cogne2 and Gra􏰠yna B. Dąbrowska1 1 Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University (NCU), Lwowska1,PL-87-100Toruń,Poland, 2 BioprocessingengineeringatPolytechNantes,campusGavy,Boulevard de l’université, 44600 Saint-Nazaire, France e-mail: justin...

The aim of this study was to isolate biofilm-forming bacteria that are capable of degrading polyhydroxybutyrate (PHB) with polyhexamethylene guanidine (PHMG) derivatives. The three types of derivatives incorporated in PHB and their concentration affected the biodegradability of the tested films in both water and compost. The PHMG derivative granula...

Background The aim of this study was to verify whether the presence of Bacillus strains and of miscanthus influence biodegradation and formed of biofilm of poly(lactic acid) (PLA) and poly(ethylene terephthalate) (PET). Methods The experiment conducted in compost soil showed that strains Bacillus subtilis and Bacillus cereus isolated from heavy me...

A series of new films with antibacterial properties has been obtained by means of solvent casting method. Biodegradable materials including polylactide (PLA), quercetin (Q) acting as an antibacterial compound and polyethylene glycol (PEG) acting as a plasticizer have been used in the process. The effect of quercetin as well as the amount of PEG on...

The present article presents the results of research on the susceptibility of polylactide, poly(ɛ-caprolactone) and mixtures to biodegradation in conditions imitating natural extracts of compost, activated sludge, sea and river water, determined by the biochemical oxygen consumption by microorganisms and susceptibility to enzymatic degradation with...

The aim of the study was to establish the influence of poly(ethylene glycol) (PEG) on the properties of potential biodegradable packaging materials with antibacterial properties, based on polylactide (PLA) and tea tree essential oil (TTO). The obtained polymeric films consisted of PLA, a natural biocide, and tea tree essential oil (5–20 wt. %) was...

The research objective of this study was to verify the effectiveness of selected rhizosphere strains in accelerating the biodegradation of plastics in cultivated soil. The study was a continuation of experiments conducted in compost soil. The experiments confirmed the ability of the two bacteria and fungi strains in biodegradation of polylactide (P...

Biodegradable materials, namely pure polylactide (PLA), poly (3,4-hydroxybutyrate) (PHB), poly(ε-caprolactone) (PCL) were investigated to assess their degradability by activated sludge. The study aimed at the isolation of biofilm-forming bacteria and the determination of their hydrolytic activity toward the PLA, PHB, and PCL with embedded PHMG deri...

This paper presents a brief characterization of bacterial biofilm, formed on polylactide, ecologically important biodegradable material. The concept of bacterial biofilm was explained, including the process of its formation as well as the structure and model of functioning in a biological environment. Three methods of its determination and document...

A modified differential display procedure was used to compare Ipomoea nil gene expression under flower inductive and non-inductive light/dark conditions and a 170 bp cDNA fragment was displayed. Screening of the cDNA library from I. nil cotyledons led to the isolation of a 577 bp cDNA clone with high nucleotide and amino acids homology to One Helix...

The work describes the effect of three types of polyhexamethylene guanidine (PHMG) derivatives on the enzymatic degradation of polylactide (PLA) based composites. In order to evaluate the degradation process caused by proteinase K, analyses of mass loss, of changes in the geometric structure of the surface and in thermal properties were determined....

Currently the use of different types of cosmetics is an integral part of our life. For this reason the stability of packaging materials in contact with popular cosmetic ingredients is crucial. In this work a study on the properties of polylactide (PLA) as potential packaging in selected surfactant solutions (sodium lauryl sulfate (SLS) and sodium l...

This study gives insight into basic physicochemical properties of new polylactide-based materials containing 1%wt of one of the three polyhexamethylene guanidine (PHMG) derivatives: PHMG stearate (LS), PHMG in granular polyethylene wax (LW) and PHMG sulfanilic acid salt (LA). The resulting materials after processing into films were studied by means...

Polyethylene oxo-degradable composites containing antibacterial substances in the form of vegetable oils: geranium, clove and eucalyptus as well as a mixture of nanoAg with nanoCu were discussed. Antibacterial film: PE-0, PE-1A, PE-2B, PE-3C, PE-4D properties were verified according to ISO 22196:2011 “Measurement of antibacterial activity on plasti...

This study presents the data summary on growth speed of selected species of fungi on some of biodegradable polymer ma-terials. Growth rate was assessed on films composed of poly(lactide), poly(ϵ-caprolactone) and poly(hydroxybutyrate) after a month of incubation in 24°C. To assess growth of fungi optical microscopy on densitometric measurements wer...

The paper presents the research results for enzymatic degradation of biodegradable materials in proteinase K. Polylactide and its composites containing a biostatic substance in the form of sulphanilic acid salt PHMG were tested as part of the research project. Three different concentrations of the biostatic substance were used: 0.2%, 0.6% and 1.0%...

The article describes a laboratory method for testing the effectiveness of paint and varnish protection products against fungi on the basis of PN-EN 15457:2014. Both the research subject and the individual stages of the study were presented. Also made a short presentation of the microorganisms used in the study.

Polyethylene was filled with 3 etheric oils (1% by mass.) and a mixt. of Ag and Cu nanoparticles and tested for interaction with bacteria. The composites were bacteria – resistant and showed antibacterial properties.

The study presents data on the distribution of selected species of lichens - Cladoniafurcata (Huds.) Schrad., C. rangiferina (L.) Weber ex F.H. Wigg. and C. uncialis (L.) Weber ex F.H. Wigg. in Torun and along its southern boundary - on a heathland on the military training ground. A comparison was carried out of the research findings on the occurre...

The purpose of this paper is to present the standards and the research methods enabling biological examination of polymeric materials or active packaging. These procedures apply to polymeric materials containing additives such as bactericides and fungicides.

Polylactide was filled with the polyhexamethylene guanidine wax (0.2–1.0% by mass) and studied for enzymatic degrdn. in proteinase K. The addn. of the wax resulted in decreasing the crystallinity and glass transition temp.

Polyethylene was filled with Cu powder (0.05–5% by mass) and tested for tensile strength, H2O vapour permeability, gloss and free surface energy. The addn. of Cu resulted in decreasing the permeability of the composites.

Polyethylene was filled with ZnO, SiO2 or Cu powders (up to 5% by mass), formed as a film by extrusion with blowing and studied for antimicrobial properties of the composite surface by std. methods. The films showed bacteriostatic properties against S. aureus.

Nisaplin or natamax-contg. films (concns. 0.2-1% by mass) were treated with compost ext. at 20°C for 7 days to det. the permeabilities of H2O vapor and O2 through the films before and after their degrdn. by std. methods. The addn. of bacteriocides resulted in improving the barrier properties. The permeablity decreased after film degrdn.

Polyhexamethylene guanidyne (PHMG) derivatives-contg. polylactide films (concn. 0.2–1.0% by mass) were exposed on action of seawater at 20°C for 7 days to study their biodegradability by detn. of BOD by microorganisms present in the water by a std. method. The addn. of PHMG resulted in deterioration of barrier properties of the film but did not aff...

Polyhexamethylene guanidynȩ (PHMG) derivatives-contg. polylactide films (concn. 0.2-1.0% by mass) were exposed on action of seawater at 20°C for 7 days to study their biodegradability by detn. of BOD by microorganisms present in the water by a std. method. The addn. of PHMG resulted in deterioration of barrier properties of the film but did not aff...

Escherichia coli and Staphylococcus aureus were able to produce biofilm on the surface of polyhydroxybutyrate (PHB), but their abundance depended on type and the concentrations of the polyhexamethylene guanidine (PHMG) derivatives introduced in PHB. Different types of PHMG derivatives inhibited S. aureus ATCC 6538P biofilm formation, but PHB with P...

The present study was aimed at investigating bactericidal properties of polylactide (PLA) films containing three different polyhexamethylene guanidine hydrochloride (PHMG) derivatives and effect of the derivatives on extracellular hydrolytic enzymes and intracellular dehydrogenases. All PHMG derivatives had a slightly stronger bactericidal effect o...

The present study involved the addition of several potentially biocidal PHMG derivatives into polylactide (PLA) for the subsequent assessment of the changes in physical properties and properties important for the practical application of the prepared composites. In addition, biofilm formation on the surface of the PLA composites as well as their bi...

Results of investigation of mass losses, geometrical surface structure changes and variations in crystallinity of poly(lactic acid) (PLA), poly(ɛ-caprolactone) (PCL) and commercially available material (PHB) consisting of poly(3,4-hydroxybutyrate) and poly(lactic acid) are presented. These structural changes occurred due to degradation of these pol...

The potato starch has been subjected to plastification with glycerol using twin-screw extruder in different conditions. The structure of obtained samples has been determined by Fourier transform infrared spectroscopy with attenuated total reflectance methods. The average molecular weights by chromatographic method and solubility in water have also...

Polylactide (PLA) was filled with derivatives of polyhexamethyleneguanidine (PHMG) to produce resp. composites studied then for their melt flow index and BOD before and after biodegradn. in river water. Sulfanilic acid salt of PHMG was the most efficient additive to the PLA composites studied.

Polylactide was mixed with triallyl isocyanurate, 1,5-dihydroxy-3-hydroxy- methylpentane triacrylate or 1,6-hexandiol diacrylate (1-5% by mass), granulated by extrusion, crosslinked by high-power electron radiation (dosis up to 90 kGy) and studied for gelation and swelling degrees detd. by dissoln. in CHCI 3 at 23°C. The addn. of triallyl isocyanur...

Ag nanoparticles were added to low.-d. polyethylene (0.2-1.0% by mass) to improve its biocide activity. The nanocomposite was homogenized by extrusion, processed to test samples by injection molding and studied for mech. strength, rheolog. properties, H2O vapor permeability and biocidic action against Escherichia coli, Bacillus subtilis and Candida...

Polylactide (PLA) crosslinked by using both triallyl isocyanurate (TAIC) and electron radiation or using dicumyl peroxide (DCP) was studied with the aim of examining the behaviour of the modified polymer under various environmental conditions. Thus, the polymer samples were subjected to composting in an industrial pile, exposed to proteinase K, or...

The influence of shungite and graphite on some properties of composites with polylactide as matrix and containing up to 50 wt% of these fillers was investigated. It was found that the composites loaded with graphite, as compared to those with shungite, exhibit superior mechanical and thermomechanical properties (higher tensile strength, impact stre...

The influence of graphite on volume and surface resistivity as well as on some thermal properties of composites containing a polylactide matrix was studied. The graphite content was up to 50 wt. %. Itwas found that the volume and surface resistivity decreased with the increasing graphite content and the percolation threshold appeared at the level o...

Polylactide was filled with shungite (5-50% by mass) to produce polylactide/shungite composites studied then for their mech., processing and functional properties. Tensile strength, elongation at break, impact strength and melt flow index decreased with increasing the shungite content, while Young modulus, barrier and antielectrostatic properties o...