Search

Amylases are industrially important enzymes which could convert starch to glucose, maltose and oligosaccharides. A bacterial strain designated as Paenibacillus chitinolyticus CKS1which was isolated from the soil of the coniferous forest, produced β-amylases using different commercial and waste substrates. Maximum β-amylases activity of 0.820 U/mL was obtained using a sugar alcohol-isomaltidex (0.5% w/v), as a substrate for microorganism growth and enzyme production. After 48 h of fermentation in a medium that contained starch (0.5%, w/v) and 0.05% v/v of ethanol, CKS1 produced β-amylase with the activity of 0.518 U/mL. The latest trends in enzyme production include utilisation of various waste products, mainly of agroindustrial origin, as a substrate for microorganisms growth. The strain CKS1 was also able to grow and produce β-amylases by using plant waste material. The plant waste substrate (PWS) contained plant biomass that is left after the ethanol extraction of various medicinal herbs (marigold and chamomile flowers, artichoke leaf, lemon balm leaf, nettle leaf, thyme leaf, yarrow shoot, yellow gentian shoot, primrose shoot, valerian shoot and chestnut and hawthorn seeds).This mixture of dried plant biomass is dissposed as such as a waste. In a medium with 0.1% (w/v) of PWS, CKS1 produced β-amylases with a maximum activity of 0.569 U/mL. The results show the potential of utilising waste plant biomass, left after ethanol extraction of medicinal herbs, in production of amylases. The application of microorganisms in β-amylase production using waste substrate is economically and environmentally accepted. Amilaze predstavljaju grupu industrijski veoma važnih enzima koji hidrolizuju skrob do glukoze, maltoze i različitih oligosaharida. Bakterijski izolat Paenibacillus chitinolyticus CKS1, izolovan iz zemljišta četinarske šume, pokazao je sposobnost proizvodnje β-amilaza tokom svog rasta na različitim komercijalnim ali i na otpadnim supstratima. Maksimalna aktivnosti β-amilaza koja je iznosila 0,820 U/mL postignuta je korišćenjem izomaltideksa, šećernog alkohola, u koncentraciji od 0,5% (w/v), kao supstrata za rast mikroorganizma i proizvodnju enzima. U podlozi sa skrobom (0,5% w/v) i sa dodatkom 0,05% (v/v) etanola, nakon 48h fermentacije, maksimum aktivnosti β-amilaza iznosila je 0,518 U/mL. Najnoviji trendovi u proizvodnji enzima odnose se na korišćenje različitih otpadnih sirovina agroindustrijskog porekla kao supstrata za rast mikroorganizma. Soj CKS1 je pokazao mogućnost korišćenja otpadnog biljnog materijala kao supstrata za rast i proizvodnju enzima amilaza. Otpadni biljni supstrat (PWS), činila je biljna masa zaostala nakon etanolne ekstrakcije različitog lekovitog bilja (cveta nevena i kamilice, lista matičnjaka, artičoke, koprive, timijana, nadzemnog dela hajdučke trave, lincure, jagorčevine i valerijane i semena divljeg kestena i gloga). Ova biljna biomasa, iz koje su ekstrahovane bioaktivne materije, meša se i odlaže kao takva u vidu otpada. Nakon rasta u podlozi sa 1,0 % (w/v) PWS, soj CKS1 proizveo je β-amilaze sa aktivnošću od 0,569 U/mL. Ovi reziltati ukazuju na mogućnost iskorišćenja otpadne biljne biomase, zaostale nakon alkoholne ekstrakcije lekovitog bilja, u procesima ekonomičnije proizvodnje amilaza. Korišćenje otpadne sirovine u mikrobnim procesima proizvodnje enzima je i ekološki mnogo prihvatljivije usled uticaja na smanjene skladištenja otpada a samim tim i sveukupnog zagađenje životne sredine.

The aim of this work was to synthesize a series of semi-interpenetrating polymer networks (semi-IPNs) of 2-hydroxyethyl acrylate and itaconic acid, in the presence of poly(N-vinylpyrrolidone). Samples were synthesized by free radical copolymerization with constant PVP and variable IA content and characterized for structural, morphological, thermal, swelling, drug release, antibacterial and cytotoxic properties. The chemical structure of samples was confirmed by Fourier-transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was used to examine morphology of samples and glass transition temperatures were determined by differential scanning calorimetry (DCS). The pH and temperature sensitivity was confirmed by measuring the dependence of the degree of swelling on pH and temperature. All samples show volume phase transition temperature (VPTT) around 47 °C. Drug release profiles were investigated using vitamin B3 as a model drug. The vitamin B3 transport mechanism was studied by fitting experimental data to five different model equations and calculating the corresponding parameters. It was also observed that IA content has a marked influence on the release profiles of vitamin B3, so the rate of drug release can be designed by changing the HEA/IA ratio. Cell viability, performed using MTT test, was high for all samples and all concentration of extract used. The antibacterial activity of hydrogels was determined against Pseudomonas aeruginosa. It turns out that IA content and time of exposure have an influence on the antibacterial potential. All samples showed satisfied cell viability. Due to these characteristics, P(HEA/IA)/PVP semi-IPNs represent interesting biomaterials for biomedical applications.

The aim of this study was the development of a non-toxic, biosynthetic antimicrobial agent which selectively acts on only one type of microorganism, and preserves the microbiota. Antimicrobial performance of biosynthesized silver nanoparticles (Ag NPs) by horsetail (Equisetum arvense L.) extract was examined against Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus, as well as yeasts Candida albicans and Saccharomyces boulardii. Also, the cytotoxicity of Ag NPs was examined toward pre-osteoblast cells. The synthetic conditions—concentration of extract, temperature, and pH—were optimized to prepare silver colloids with different particle size distributions and long-term stability. The obtained samples were characterized using transmission electron microscopy, X-ray diffraction analysis, and absorption spectroscopy. The smaller-sized Ag NPs (~ 10–20 nm), prepared at a lower temperature (20 °C), showed better antimicrobial performance against E. coli compared to larger ones (~ 40–60 nm), prepared at high temperature (100 °C). On the other hand, both samples did not display any toxic action against bacteria S. aureus, or yeasts C. albicans and S. boulardii. Non-cytotoxic behavior of Ag NPs toward pre-osteoblast cells was observed for the concentrations of silver ≤ 2.25 and ≤ 4.5 mg L−1 for 10–20 and 40–60 nm-sized Ag NPs, respectively. Biosynthesized Ag NPs by horsetail extract display selective toxic action against E. coli at the ecologically acceptable concentration level., Financial support for this study was granted by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Projects III 45020 and TR 31035).

Sugar beet pulp (SBP) and molasses, as an agro industrial waste material, are produced in large amounts annually. Thus, a major challenge nowadays is to develop procedures that could increase the value of the generated waste. In this study, SBP as a support for cell immobilization and molasses as a source of nutrients were used for a dextransucrase (DS) production by Leuconostoc mesenteroides T3. The influence of SBP in native form (SBP-N) and after treatment with NaOH (SBP-NaOH) on DS production was investigated. The optimal medium composition for the maximum DS production was determined by varying the concentration of molasses, SBP, and sucrose. The maximum DS yield of 2.02 U/ml was obtained in the medium with 2.5 % of molasses, 2.5 % SBP-NaOH, and 4 % of sucrose concentration. Scanning electron microscopy (SEM) showed immobilization of Lc. mesenteroides T3 cells onto SBP-NaOH. According to the obtained results, the production of DS on molasses could be improved by using NaOH-treated SBP as a carrier for whole-cell immobilization. Our study reveals the basis for the development of process for DS production with additional reduction of expenses by using waste materials for obtaining the valuable biotechnological product.

The antibacterial ability of in situ prepared nanometer-sized silver particles, immobilized in agar-agar films, was studied as a function of the concentration of co-dopant, magnesium ions. Content of inorganic components in hybrid films was determined using inductively coupled plasma optic emission spectroscopy, and found to be low (

This study was aimed to highlight the possibility of cotton fabric impregnation with silver nanoparticles synthesized by dextran isolated from Leuconostoc mesenteroides T3 in order to obtain antimicrobial properties. The fabrication of dextran was proved by FTIR spectroscopy. Particle sizes of synthesized dextran and silver nanoparticles were measured by dynamic light scattering method. The presence of silver nanoparticles on the surface of cotton fabric was confirmed by scanning electron microscopy, X-ray diffraction measurements and reflectance spectrophotometry. Antimicrobial activity of cotton fabric impregnated with silver nanoparticles was tested against bacteria Escherichia coli and Staphylococcus aureus, and fungus Candida albicans. The results indicated that synthesized silver nanoparticles can provide satisfactory antimicrobial activity. However, maximum reduction (99.9%) of all tested microorganisms can be obtained only when 1.0mmolL(-1) colloid consisting of silver nanoparticles is applied.

In this study, three series of hydrogels based on 2-hydroxyethyl acrylate and itaconic acid, unloaded, with incorporated copper(II) ions and reduced copper, were successfully prepared, characterized and evaluated as novel wound healing materials. Fourier transform infrared spectroscopy (FTIR) confirmed the expected structure of obtained hydrogels. Scanning electron microscopy (SEM) revealed porous morphology of unloaded hydrogels, and the morphological modifications in case of loaded hydrogels. Thermal characteristics were examined by differential scanning calorimetry (DSC) and the glass transition temperatures were observed in range of 12-50 degrees C. Swelling study was conducted in wide range of pHs at 37 degrees C, confirming pH sensitive behaviour for all three series of hydrogels. The in vitro copper release was investigated and the experimental data were analysed using several models in order to elucidate the transport mechanism. The antimicrobial assay revealed excellent antimicrobial activity, over 99% against Escherichia coli, Staphylococcus aureus and Candida albicans, as well as good correlation with the copper release experiments. In accordance with potential application, water vapour transmission rate, oxygen penetration, dispersion characteristics, fluid retention were observed and the suitability of the hydrogels for wound healing application was discussed.

The TiO

The aim of this study was to develop dextran-based edible films plasticized by sorbitol. In order to optimise the film-forming formulation, response surface methodology was used. The influence of dextran and sorbitol concentration on the mechanical and water vapour barrier properties of obtained films was investigated. The results showed that both parameters exhibited significant effect on the water vapour permeability of a film. Both dextran and sorbitol concentration had significant influence on tensile strength and elongation at break, whereas only sorbitol concentration had significant effect on Young’s modulus. After optimisation by desirability approach, it was found that a film made of 3.40 wt% of dextran and 20.43 wt% of sorbitol showed the lowest water vapour permeability and the highest tensile strength and elasticity.

The TiO2 based hybrid supports with different functional groups (amino, glutaraldehyde or epoxy) were prepared and their influence on immobilization of dextransucrase (DS) was studied. Novel synthetic route for surface modification of TiO2 with amino and glutaraldehyde groups was developed taking advantage of charge transfer complex (CTC) formation between surface Ti atoms and salicylate-type of ligand (5 aminosalicylic acid (5-ASA)). The proposed coordination of 5-ASA to the surface of TiO2 powder and optical properties of CTC was presented. The pristine TiO2 and amino functionalized TiO2 have higher sorption capacity for DS (12.6 and 12.0 mg g(-1), respectively) compared to glutaraldehyde and epoxy activated supports (9.6 and 9.8 mg g(-1) respectively). However, immobilized enzyme to either glutaraldehyde or epoxy functionalized TiO2 have almost two times higher expressed activities compared to pristine TiO2 support (258, 235 and 142 IU g(-1), respectively). Thermal stability of enzyme immobilized on glutaraldehyde and epoxy functionalized supports was studied at 40 degrees C, as well as operational stability under long-run working conditions in repeated cycles. After five cycles, DS imobilized on glutaraldehyde activated support retained almost 70% of its initial expressed activity, while, after five cycles, performance of DS immobilized on epoxy activated support was significantly lower (15%).

Transport packaging factories generate a large amount of wastewater that contains residuals of starch glue. These residuals could be used as substrates for microorganism growth and enzyme production. In this study, beta-amylase production using a new strain Paenibacillus chitinolyticus CKS1 was optimized using wastewater from a Serbian transport packaging factory. The optimization of beta-amylase production was carried out using Response Surface Methodology (RSM). A Central Composite Design under the RSM with four interacting parameters (incubation time, inoculum concentration, casein hydrolysate concentration and yeast extract concentration) was employed to identify the optimal conditions for maximum beta-amylase activity (334.20 U L-1) as 62 h of incubation with 2.40% inoculum, 2.02 g L-1 casein hydrolysate and 3.98 g L-1 yeast extract. High performance liquid chromatography showed that the P. chitinolyticus CKS1 strain hydrolyzed starch to form maltose as a major product. Due to the application of wastewater as an inexpensive material for enzyme and maltose production it may be considered that the economic and eco-friendly aspects of this method are very promising.

In this work, antimicrobial bioinspired films made from chitosan incorporated with triclosan were investigated. The tensile strenght of these films were in the range of 33 and 39 MPa, which presented satisfied mechanical stability comparable to the synthetic-based packages commonly used in industry. The addition of triclosan enhanced thermal stability and antimicrobial activity of chitosan films against Escherichia coli and Staphylococus aureus . Results obtained in this work demonstrated that chitosan/triclosan films could be potentially used as an eco-sustainable package in healthcare sector to prevent infections/contaminations.

The interaction of the tryptophan functionalized Ag nanoparticles and live Candida albicans cells was studied by synchrotron excitation deep-ultraviolet (DUV) fluorescence imaging at the DISCO beamline of Synchrotron SOLEIL. DUV imaging showed that incubation of the fungus with functionalized nanoparticles results in significant increase in the fluorescence signal. The analysis of the images revealed that the interaction of the nanoparticles with (pseudo)hyphae polymorphs of the diploid fungus was less pronounced than in the case of yeast cells or budding spores. The changes in the intensity of the fluorescence signals of the cells after incubation were followed in [327-353 nm] and [370-410 nm] spectral ranges that correspond to the fluorescence of tryptophan in non-polar and polar environment, respectively. As a consequence of the environmental sensitivity of the silver-tryptophan fluorescent nanoprobe, we were able to determine the possible accumulation sites of the nanoparticles. The analysis of the intensity decay kinetics showed that the photobleaching effects were more pronounced in the case of the functionalized nanoparticle treated cells. The results of time-integrated emission in the mentioned spectral ranges suggested that the nanoparticles penetrate the cells, but that the majority of the nanoparticles attach to the cells surfaces. (C) 2017 Elsevier B.V. All rights reserved.