Support Materials of Organic and Inorganic Origin as Platforms for Horseradish Peroxidase Immobilization: Comparison Study for High Stability and Activity Recovery.

In the presented study, a variety of hybrid and single nanomaterials of various origins were tested as novel platforms for horseradish peroxidase immobilization. A thorough characterization was performed to establish the suitability of the support materials for immobilization, as well as the activity and stability retention of the biocatalysts, which were analyzed and discussed. The physicochemical characterization of the obtained systems proved successful enzyme deposition on all the presented materials. The immobilization of horseradish peroxidase on all the tested supports occurred with an efficiency above 70%. However, for multi-walled carbon nanotubes and hybrids made of chitosan, magnetic nanoparticles, and selenium ions, it reached up to 90%. For these materials, the immobilization yield exceeded 80%, resulting in high amounts of immobilized enzymes. The produced system showed the same optimal pH and temperature conditions as free enzymes; however, over a wider range of conditions, the immobilized enzymes showed activity of over 50%. Finally, a reusability study and storage stability tests showed that horseradish peroxidase immobilized on a hybrid made of chitosan, magnetic nanoparticles, and selenium ions retained around 80% of its initial activity after 10 repeated catalytic cycles and after 20 days of storage. Of all the tested materials, the most favorable for immobilization was the above-mentioned chitosan-based hybrid material. The selenium additive present in the discussed material gives it supplementary properties that increase the immobilization yield of the enzyme and improve enzyme stability. The obtained results confirm the applicability of these nanomaterials as useful platforms for enzyme immobilization in the contemplation of the structural stability of an enzyme and the high catalytic activity of fabricated biocatalysts.

Advances in electrospun materials for the adsorption and separation of environmental pollutants: A comprehensive review.

Despite a broad range of new techniques developed, adsorption methods remain one of the technologies of choice for the removal of contaminants. However, significant progress has also been made in these, which finds reflection in a new spectrum of adsorbents that can be used. This comprehensive review discusses properties, advantages, and perspectives on the use of custom-made electrospun adsorbents in the processes of heavy metals, agrochemicals, and microplastic contaminants removal from the environment. It presents the versatility and adaptability of materials that can be used as electrospun fibers matrix, also considering the mechanism and parameters of the sorption process carried out with them. The presented review proves, that due to the use of new, custom-made sorbents, such as electrospun materials, the adsorption processes still possess great application potential and development opportunities to provide an attractive and effective alternative to other remediation techniques.

Nanomechanical changes in probiotic bacteria under antibiotics exposure: Implications on Lactobacillus biofilm formation.

Recognition of the microbial cell's surface constituents' biophysical properties is an important research topic, allowing a better understanding of the cell's behaviour under different conditions. Atomic force microscopy (AFM) was employed in this study to analyse the basis of the nanomechanical changes in probiotic bacteria under nitrofurantoin, furazolidone, and nitrofurazone exposure. Recorded significant changes in the two Lactobacillus strains cells morphology, topography, and adhesion parameters resulted in the increase of the cells' longitude (up to 2.58 µm), profile height (by around 0.50 µm), and decrease in the adhesion force (up to 13.58 nN). Young's modulus and adhesion energy decreased within 96 h, however with no negative effect on the cells' morphology or loss of structural integrity. Observed modifications present the mode of action of the 5-nitrofuran derivative antibiotics on probiotic biofilm formation and suggest activation of the multilevel adaptation mechanisms to counteract unfavorable environments. A visual change in bacterial morphology such as an increased surface-to-volume ratio might be a link between molecular-level events and outcomes in individual cells and biofilms. This paper for the first time shows, that these antibiotics affect the properties of non-target microorganisms as lactobacilli, and might impair biofilm formation. However, the degree of such transformations depends on the delivered active substance.

Study of Membrane-Immobilized Oxidoreductases in Wastewater Treatment for Micropollutants Removal.

The development of efficient strategies for wastewater treatment to remove micropollutants is of the highest importance. Hence, in this study, we presented a rapid approach to the production of biocatalytic membranes based on commercially available cellulose membrane and oxidoreductase enzymes including laccase, tyrosinase, and horseradish peroxidase. Effective enzyme deposition was confirmed based on Fourier transform infrared spectra, whereas results of spectrophotometric measurements showed that immobilization yield for all proposed systems exceeded 80% followed by over 80% activity recovery, with the highest values (over 90%) noticed for the membrane-laccase system. Further, storage stability and reusability of the immobilized enzyme were improved, reaching over 75% after, respectively, 20 days of storage, and 10 repeated biocatalytic cycles. The key stage of the study concerned the use of produced membranes for the removal of hematoporphyrin, (2,4-dichlorophenoxy)acetic acid (2,4-D), 17α-ethynylestradiol, tetracycline, tert-amyl alcohol (anesthetic drug), and ketoprofen methyl ester from real wastewater sampling at various places in the wastewater treatment plant. Although produced membranes showed mixed removal rates, all of the analyzed compounds were at least partially removed from the wastewater. Obtained data clearly showed, however, that composition of the wastewater matrix, type of pollutants as well as type of enzyme strongly affect the efficiency of enzymatic treatment of wastewater.

Immobilized Lipase in Resolution of Ketoprofen Enantiomers: Examination of Biocatalysts Properties and Process Characterization.

In this study, lipase from Aspergillus niger immobilized by physical immobilization by the adsorption interactions and partially interfacial activation and mixed physical immobilization via interfacial activation and ion exchange was used in the kinetic resolution of the ketoprofen racemic mixture. The FTIR spectra of samples after immobilization of enzyme-characteristic signals can be seen, and an increase in particle size diameters upon immobilization is observed, indicating efficient immobilization. The immobilization yield was on the level of 93% and 86% for immobilization unmodified and modified support, respectively, whereas activity recovery reached around 90% for both systems. The highest activity of immobilized biocatalysts was observed at pH 7 and temperature 40 °C and pH 8 and 20 °C for lipase immobilized by physical immobilization by the adsorption interactions and partially interfacial activation and mixed physical immobilization via interfacial activation and ion exchange, respectively. It was also shown that over a wide range of pH (from 7 to 10) and temperature (from 20 to 60 °C) both immobilized lipases retained over 80% of their relative activity, indicating improvement of enzyme stability. The best solvent during kinetic resolution of enantiomers was found to be phosphate buffer at pH 7, which obtained the highest efficiency of racemic ketoprofen methyl ester resolution at the level of over 51%, followed by enantiomeric excess 99.85% in the presence of biocatalyst obtained by physical immobilization by the adsorption interactions and partially interfacial activation.

Enzymatic membrane reactor in xylose bioconversion with simultaneous cofactor regeneration.

In this study, we present the concept of co-immobilization of xylose dehydrogenase and alcohol dehydrogenase from Saccharomyces cerevisiae on an XN45 nanofiltration membrane for application in the process of xylose bioconversion to xylonic acid with simultaneous cofactor regeneration and membrane separation of reaction products. During the research, the effectiveness of the co-immobilization of enzymes was confirmed, and changes in the properties of the membrane after the processes were determined. Using the obtained biocatalytic system it was possible to obtain 99% xylonic acid production efficiency under optimal conditions, which were 5 mM xylose, 5 mM formaldehyde, ratio of NAD+:NADH 1:1, and 60 min of reaction. Additionally, the co-immobilization of enzymes made it possible to improve stability of the co-immobilized enzymes and to carry out xylose conversion in six consecutive cycles and after 7 days of storage at 4 °C with over 90% efficiency. The presented data confirm the effectiveness of the co-immobilization, improvement of the stability and reusability of the biocatalysts, and show that the obtained enzymatic system is promising for use in xylose bioconversion and simultaneous regeneration of nicotinamide cofactor.

New Biocomposite Electrospun Fiber/Alginate Hydrogel for Probiotic Bacteria Immobilization.

Biotechnological use of probiotic microorganisms involves providing them with appropriate conditions for growth, but also protection against environmental changes caused by an exchange of the medium, isolation of metabolites, etc. Therefore, the research on effective immobilization of probiotic microorganisms should be focused in this direction. The present study aimed to evaluate the effectiveness of an innovative hybrid immobilization system based on electrospun nanofibers and alginate hydrogel. The analyses carried out included the study of properties of the initial components, the evaluation of the degree and durability of cell immobilization in the final material, and their survival under stress conditions. Effective binding of microorganisms to the hydrogel and nanofibers was confirmed, and the collected results proved that the proposed biocomposite is an efficient method of cell protection. In addition, it was shown that immobilization on electrospun nanofibers leads to the preservation of the highest cell activity and the least cell growth restriction as compared to free or lyophilized cells only. The completed research opens new perspectives for the effective immobilization of microorganisms of significant economic importance.

Significance of the presence of antibiotics on the microbial consortium in wastewater - The case of nitrofurantoin and furazolidone.

Antibiotics in wastewater leads to migration of pollutants and disrupts natural processes of mineralization of organic matter. In order to understand the mechanism of this, research was undertaken on the influence of nitrofurantoin (NFT) and furazolidone (FZD), on the behaviour of a consortium of microorganisms present in a model wastewater in a bioreactor. Our study confirmed biodegradation of the antibiotics by the microbial consortium, with the degradation efficiency within 10 days of 65% for FZD, but only 20% for NFT. The kinetic study proved that the presence of analysed antibiotics had no adverse effect on the microbes, but the consortium behaviour differ significantly with the NFT reducing the consumption of organic carbon in wastewater and increasing the production of extracellular biopolymeric and volatile organic compounds, and the FZD reducing assimilation of other carbon sources to a less extent, at the expense of cellular focus on biodegradation of this antibiotic.

Nitrofurazone Removal from Water Enhanced by Coupling Photocatalysis and Biodegradation.

(1) Background: Environmental contamination with antibiotics is particularly serious because the usual methods used in wastewater treatment plants turn out to be insufficient or ineffective. An interesting idea is to support natural biodegradation processes with physicochemical methods as well as with bioaugmentation with efficient microbial degraders. Hence, the aim of our study is evaluation of the effectiveness of different methods of nitrofurazone (NFZ) degradation: photolysis and photodegradation in the presence of two photocatalysts, the commercial TiO2-P25 and a self-obtained Fe3O4@SiO2/TiO2 magnetic photocatalyst. (2) Methods: The chemical nature of the photocatalysis products was investigated using a spectrometric method, and then, they were subjected to biodegradation using the strain Achromobacter xylosoxidans NFZ2. Additionally, the effects of the photodegradation products on bacterial cell surface properties and membranes were studied. (3) Results: Photocatalysis with TiO2-P25 allowed reduction of NFZ by over 90%, demonstrating that this method is twice as effective as photolysis alone. Moreover, the bacterial strain used proved to be effective in the removal of NFZ, as well as its intermediates. (4) Conclusions: The results indicated that photocatalysis alone or coupled with biodegradation with the strain A. xylosoxidans NFZ2 leads to efficient degradation and almost complete mineralization of NFZ.

Surfactant addition in diesel oil degradation - how can it help the microbes?

PURPOSE: Despite wide research on bioremediation of hydrocarbon-contaminated soil, the mechanisms of surfactant-enhanced bioavailability of the contaminants are still unclear. The presented study was focused on the in-depth description of relationships between hydrocarbons, bacteria, and surfactants. In order to that, the biodegradation experiments and cell viability measurements were conducted, and the properties of cell surface were characterized. METHODS: MTT assay was employed to measure plant extracts toxicity to microbes. Then, membrane permeability changes were evaluated, followed by diesel oil biodegradation in the presence of surfactants measurements by GCxGC-TOFMS and PCR-RAPD analysis. RESULTS: Our study undoubtedly proves that different surfactants promote assimilation of different groups of hydrocarbons and modify cell surface properties in different ways. Increased biodegradation of diesel oil was observed when cultures with Acinetobacter calcoaceticus M1B were supplemented with Saponaria officinalis and Verbascum nigrum extracts. Interestingly, these surfactants exhibit different influences on cell surface properties and their viability in contrast to the other surfactants. Moreover, the preliminary analyses have shown changes in the genome caused by exposure to surfactants. CONCLUSIONS: The results indicated that the benefits of surfactant use may be related to deep modification at the omics level, not only that of cell surface properties and confirms the complexity of the interactions between bacterial cells, pollutants and surfactants.

Evaluation of the physico-chemical properties of hydrocarbons-exposed bacterial biomass.

In the efforts for the removal of hazardous materials from the environment biological processes are a valuable tool. Although much attention has been paid to the changes in bacteria at the omics level, another, physical-chemical perspective on the issue is essential, as little is known of microbial response to continuous exposition on harmful substances. This study provides in-depth characterization of the physical-chemical parameters of bacterial biomass after hydrocarbons exposure. To provide comparability of the harmful effects of chlorotoluenes and xylenes non-exposed and 12-months hydrocarbons exposed cells were analyzed, using the advanced spectrometric methods, inverse gas chromatography and low-temperature N2 sorption to evaluate acid-base as well as dispersive properties of the studied biomass. Presented results indicate P. fluorescens B01 cells strategy aimed at protecting the cell, thus lowering its' biodegradation efficiency as a result of metabolic stress. The outcome of the study was that prolonged exposure to pollutants might reduce the bioavailability of hydrocarbons to bacteria cells, and consequently decrease the effectiveness of decontamination of polluted sites by indigenous microorganisms.

Multilevel changes in bacterial properties on long-term exposure to hydrocarbons and impact of these cells on fresh-water communities.

To handle the impact of habitat transformations, the microbial cells developed mechanisms aimed at adjustment of their biological processes in response to signals indicating environmental changes. One of the first changes in their properties is observed on their surface, which has direct contact with the dynamically varying surroundings. In this study, we present results of changes in the cell surface properties which may have a decisive impact on the xenobiotics' bioavailability and microbial cell survival. These changes influence their ability to remove xenobiotics by accelerating and empowering this process. Moreover, the application of microorganisms exposed for long-term to hydrocarbons in bioremediation processes might have positive impact on biodegradation of the latter in the natural environment as well as natural microbial community diversity. This study demonstrates a variety of microbial cell mechanisms of adaptation to long-term exposure to hydrocarbons and their potential as the bioremediation tools.

Co-Immobilization of Glucose Dehydrogenase and Xylose Dehydrogenase as a New Approach for Simultaneous Production of Gluconic and Xylonic Acid.

The conversion of biomass components catalyzed via immobilized enzymes is a promising way of obtaining valuable compounds with high efficiency under mild conditions. However, simultaneous transformation of glucose and xylose into gluconic acid and xylonic acid, respectively, is an overlooked research area. Therefore, in this work we have undertaken a study focused on the co-immobilization of glucose dehydrogenase (GDH, EC 1.1.1.118) and xylose dehydrogenase (XDH, EC 1.1.1.175) using mesoporous Santa Barbara Amorphous silica (SBA 15) for the simultaneous production of gluconic acid and xylonic acid. The effective co-immobilization of enzymes onto the surface and into the pores of the silica support was confirmed. A GDH:XDH ratio equal to 1:5 was the most suitable for the conversion of xylose and glucose, as the reaction yield reached over 90% for both monosaccharides after 45 min of the process. Upon co-immobilization, reaction yields exceeding 80% were noticed over wide pH (7-9) and temperature (40-60 °C) ranges. Additionally, the co-immobilized GDH and XDH exhibited a significant enhancement of their thermal, chemical and storage stability. Furthermore, the co-immobilized enzymes are characterized by good reusability, as they facilitated the reaction yields by over 80%, even after 5 consecutive reaction steps.

Increased biological removal of 1-chloronaphthalene as a result of exposure: A study of bacterial adaptation strategies.

Effective biodegradation of hydrophobic pollutants, such as 1-chloronaphthalene, is strictly associated with the adaptation of environmental bacteria to their assimilation. This study explores the relation between the modifications of cell properties of bacteria belonging to Pseudomonas and Serratia genera resulting from a 12-month exposure to 1-chloronaphthalene, and their biodegradation efficiency. In the presented study, both bacterial strains exhibited higher (70%) degradation of this compound after exposure compared to unexposed (55%) systems. This adaptation can be associated with increased ratio of polysaccharides in the outer layers of bacterial cells, which was confirmed using infrared spectroscopy analysis. Additionally, the analysis of Raman spectra indicated conformational changes of extracellular carbohydrates from α- to ß-anomeric structure. Moreover, the changes in the cell surface hydrophobicity and cell membrane permeability differed between the strains and the Pseudomonas strain exhibited more significant modifications of these parameters. The results suggest that adaptation strategies of both tested strains are different and involve diverse reconstructions of the cell wall and membranes. The results provide a novel and deep insight into the interactions between environmental bacterial strains and chloroaromatic compounds, which opens new perspectives for applying spectrometric methods in investigation of cell adaptation strategies as a result of long-term contact with toxic pollutants.

Environmental Aspects of the Use of Hedera helix Extract in Bioremediation Process.

This paper analyzes the impact of saponins from English ivy leaves on the properties of environmental bacterial strains and hydrocarbon degradation ability. For this purpose, two bacterial strains, Raoultella ornitinolytica M03 and Acinetobacter calcoaceticus M1B, have been used in toluene, 4-chlorotoluene, and α,α,α-trifluorotoluene biodegradation supported by Hedera helix extract. Moreover, theeffects of ivy exposition on cell properties and extract toxicity were investigated. The extract was found to cause minor differences in cell surface hydrophobicity, membrane permeability, and Zeta potential, although it adhered to the cell surface. Acinetobacter calcoaceticus M1B was more affected by the ivy extract; thus, the cells were more metabolically active and degraded saponins at greater amounts. Although the extract influenced positively the cells' viability in the presence of hydrocarbons, it could have been used by the bacteria as a carbon source, thus slowing down hydrocarbon degradation. These results show that the use of ivy saponins for hydrocarbon remediation is environmentally acceptable but should be carefully analyzed to assess the efficiency of the selected saponins-rich extract in combination with selected bacterial strains.

Properties and potential application of efficient biosurfactant produced by Pseudomonas sp. KZ1 strain.

Increasing use of biosurfactants has stimulated the search for new and efficient biosurfactant-producing bacterial strains, preferably nonpathogenic ones. The aim of the present study was to characterize a new isolated Pseudomonas sp. KZ1 strain and its exocellular surface active compounds. After examining several mineral media of different compositions, the bioreactor-scale production of biosurfactants under optimum conditions was tested. Then, the composition of the isolated biosurfactants was investigated by Fourier-transform infrared spectroscopy and gas chromatography-mass spectrometry analysis and their surface active properties were characterized by adsorption parameters. The results indicated that the Pseudomonas sp. KZ1 biosurfactant had the critical micelle concentration of 0.12 g L-1 and decreased the surface tension decreased to 31.7 mN m-1. Moreover, the biosurfactant increased the rate of biodegradation of diesel oil by the strains: Pseudomonas sp. KZ1, Pseudomonas sp. OS4 and Achromobacter sp. KW1. The obtained biosurfactant showing attractive properties is a promising and much 'greener' alternative in the application for surfactant-enhanced biodegradation of hydrocarbons.

Biological impact of octyl d-glucopyranoside based surfactants.

Development of many branches of industry has stimulated the search for new, effective surfactants with interesting properties. Potential use of alkyl glucose derivatives on a large scale, raises questions about the possible risks associated with their entry into the natural environment. To be able to evaluate this risk, the aim of the study was to determine the physicochemical properties of octyl d-glucopyranoside and its three derivatives: N-(octyl d-glucopyranosiduronyl)aspartic acid, N-(octyl d-glucopyranosiduronyl)glicyne and octyl d-glucopyranosiduronic acid. Moreover, their biodegradability by pure bacterial strains and biocenosis present in river water was examined. While descriptions of sugar-based surfactants on microbial cells are limited, the essential element of the study was to determine the effect of surfactants on cell surface properties of microorganisms isolated from activated sludge and compare it to the effects of the petroleum based surfactants and the surfactants produced from renewable materials. The results obtained indicate that physicochemical properties of surface active agents differ depending on the presence of functional groups in the surfactants molecules. What is more, the presence of amino acid substituent in the derivatives of octyl d-glucopyranoside resulted in a slight decrease in the surfactants biodegradation efficiency, in comparison to the compounds that did not contain such a substituent, prolonging this process from 5 to 10 days. Interestingly, even relatively slightly different derivatives modified the cell surface properties in a different way. Importantly, the surfactants based on octyl d-glucopyranoside have less negative impact on environmental microorganism and better biodegradability than the surfactant synthesized from petroleum products.

Butylbenzene and tert-Butylbenzene-Sorption on Sand Particles and Biodegradation in the Presence of Plant Natural Surfactants.

The effects of hydrocarbons sorption on sand and saponins presence in the system on butylbenzene and tert-butylbenzene biological degradation was investigated. Additionally, the impact of saponins-containing plant extracts on environmental microorganisms was studied. Results of cell surface property measurements in samples with saponins only revealed changes in cell surface hydrophobicity, electrokinetic potential and membrane permeability when compared to corresponding values for glucose-grown microbes. Subsequently, in sorption experiments, the hydrocarbon adsorption kinetics in bacteria-free samples were better explained with the pseudo-second order kinetic model as compared to the pseudo-first order and intraparticular diffusion models. Moreover, the equilibrium data fitted better to the Freundlich isotherm for both benzene derivatives. In the samples combining hydrocarbons sorption and biological degradation in the presence of saponins, alkane-substituted hydrocarbons removal was accelerated from 40% to 90% after 14 days and the best surfactant in this aspect was S. officinalis extract.

Environmental biodegradation of halophenols by activated sludge from two different sewage treatment plants.

Halophenols make a group of aromatic compounds that are resistible to biodegradation by environmental microorganisms. In this study, the biodegradation of 4-bromo-, 4-chloro- and 4-fluorophenols was studied with two types of activated sludges (from a small rural plant and from a bigger municipal plant) as an inoculum. Because of their wide use, surfactants are present in the wastewater and inhibitors enhance the biodegradation of different pollutants; the influence of natural surfactants on halophenols' biodegradation was also tested. Both types of activated sludge contained bacterial strains which were active in the halophenols' biodegradation process. The coexistence of surfactants and halophenols in the wastewater does not prevent microorganisms from effective halophenols' biodegradation. Moreover, surfactants can enhance the effectiveness of halophenols' removal from the environment. Different cell surface modifications of two isolated bacterial strains were observed in the same system of halophenols with or without surfactants. Halophenols and surfactants may also induce changes in bacteria cell surface properties.

Saponaria officinalis L. extract: Surface active properties and impact on environmental bacterial strains.

Plant-derived surfactants are characterised by low toxicity, high biodegradability and environmental compatibility. They therefore have many applications; for instance, they can be used in bioremediation to accelerate biodegradation processes, especially of hydrophobic pollutants. This paper analyses the properties of an extract from Saponaria officinalis L. containing saponins and its impact on bacterial strains isolated from soil, as well as its potential for application in hydrocarbon bioremediation. The tested extract from Saponaria officinalis L. contains gypsogenin, hederagenin, hydroxyhederagenin and quillaic acid aglycone structures and demonstrates good emulsification properties. Contact with the extract led to modification of bacterial cell surface properties. A decrease in cell surface hydrophobicity and an increase in membrane permeability were recorded in the experiments. An increase of up to 63% in diesel oil biodegradation was also recorded for Pseudomonas putida DA1 on addition of 1gL-1 of saponins from Saponaria officinalis L. Saponaria extract showed no toxic impact on the tested environmental bacterial strains at the concentration used in the biodegradation process.