Rafal Rakoczy

Rafal Rakoczy

Professor

About

117
Publications
24,675
Reads
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1,106
Citations
Citations since 2016
73 Research Items
933 Citations
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250

Publications

Publications (117)
Article
Full-text available
The corrosion process leads to high power consumption, high maintenance costs and the loss of commercial income during downtime in various branches of industry. The proper methods to measure and forecast the corrosion process would help intervene in process production where corrosion is a common phenomenon. Therefore, the main aim of this experimen...
Article
This research involves the influence of tank scale and, additionally, stirrer speed, the volumetric gas flow rate, the sucrose concentration in aqueous solution, and the yeast suspension concentration on the hydrodynamics of gas-liquid and gas-biophase-liquid systems. A stirred tank with internal diameters of T=0.288 m, and T=0.634 m was filled wit...
Chapter
An electromagnetic field (EMF) has been shown to have various stimulatory or inhibitory effects on microorganisms. Over the years, growing interest in this topic led to numerous discoveries suggesting the potential applicability of EMF in biotechnological processes. Among these observations are stimulative effects of this physical influence resulti...
Article
The growing interest in bacteriophages and antibiotics' combined use poses new challenges regarding this phenomenon's accurate description. This study aimed to apply the PhageScore methodology to assess the phage-antibiotic combination activity in liquid bacterial culture. For this purpose, previously described Acinetobacter infecting phages vB_Aba...
Article
Full-text available
This work presents the results ofa study which concerns the influence of rotating magnetic field (RMF) on the antibacterial performance of commercial pine essential oil. A suspension of essential oil in saline solution and Escherichia coli were exposed to the rotating magnetic Afield (the frequency of electrical current supplied by a RMF generator...
Article
Effective and cheap water purification is one of the most important tasks facing humanity. Among various methods of water treatment, heterogeneous photocatalysis is probably most recommended. However, the application of artificial sources of irradiation results in high investment and operating costs. Accordingly, either vis-responsive photocatalyst...
Article
Full-text available
Bacterial cellulose (BC) is a natural polymer produced by acetic acid bacteria, e.g. Komagataeibacter xylinus. BC is often preferred over plant cellulose and finds many medicinal and environmental protection applications thanks to its high purity, water holding capacity, tensile strength, and biocompatibility. This work is aimed to test the sequent...
Conference Paper
Full-text available
Wprowadzenie Publikacje "policy brief" mają na celu syntetyczne zdefiniowanie wybranych zagadnień i problemów. Z jednej strony wiążą się zazwyczaj ze sferą naukową, ale z drugiej-również z (szeroko rozumianą) sferą polityk publicznych. Do tych ostatnich można również zaliczyć zagadnienia dotyczące polityki naukowej. Publikacje "policy brief" porząd...
Article
Full-text available
Growing interest in bacteriophage research and use, especially as an alternative treatmentoption for multidrug-resistant bacterial infection, requires rapid development of production methodsand strengthening of bacteriophage activities. Bacteriophage adsorption to host cells initiates theprocess of infection. The rotating magnetic field (RMF) is a...
Article
Full-text available
Experiments describing properties of nanomaterials on bacteria are frequently limited to the disk diffusion method or other end-point methods indicating viability or survival rate in plate count assay. Such experimental design does not show the dynamic changes in bacterial physiology, mainly when performed on reference microorganisms ( Escherichia...
Article
Full-text available
Pseudomonas aeruginosa is a bacterium producing industrially utile metabolites, such as rhamnolipids, biopolymers, and pigments. Pyocyanin, the most studied example of pigments, is a virulence factor that also shows the potential for application in, e.g., agriculture, anticancer therapy, and energy production. Therefore, potential inhibitors and st...
Article
Full-text available
Pseudomonas aeruginosa is a producer of desired secondary metabolites, including pyocyanin. Potential uses of this pigment urge a search for improved production methods. Recent trends in bioprocessing show the potential of the use of electromagnetic fields (EMFs) to influence the growth of microorganisms and even modulate the concentration of biopr...
Article
Full-text available
Bacterial infectious diseases are serious health problem which extends to economic and social complications. Moreover, bacterial antibiotic resistance, lack of suitable vaccine or emergence of new mutations is forcing the development of novel antimicrobial agents. The objective of this study is to synthesize and characterize star-like zinc oxide na...
Article
Full-text available
The primary purpose of this study is to develop a novel type of magnetically assisted reactor for the production of bacterial biomass. Following this aim, we applied a ferrofluidic or water coat around the culture tubes that modified the generated rotating magnetic field (RMF) characteristics. Fe3O4 nanoparticles have been described, and their modu...
Article
Full-text available
The aim of this study was to demonstrate the applicability of a novel magnetically assisted external-loop airlift bioreactor (EL-ALB), equipped with rotating magnetic field (RMF) generators for the preparation of Komagataeibacter xylinus inoculum during three-cycle repeated fed-batch cultures , further used for bacterial cellulose (BC) production....
Article
Full-text available
Sewer systems are an integral part of our modern civilization and are an imperative underground infrastructure asset that our society relies on. In Western Europe alone, 92% of the resident pollution is connected to sewer systems. This extensive coverage of sewerage systems presents an ideal habitation for microorganisms to strive. Sewers can be co...
Article
Full-text available
Here, we designed paper sheets coated with chitosan, bacterial cellulose (nanofibers), and ZnO with boosted antibacterial and mechanical activity. We investigated the compositions, with ZnO exhibiting two different sizes/shapes: (1) rods and (2) irregular sphere-like particles. The proposed processing of bacterial cellulose resulted in the formatio...
Article
Full-text available
Bacterial cellulose membranes (BCs) are becoming useful as a drug delivery system to the skin. However, there are very few reports on their application of plant substances to the skin. Komagataeibacter xylinus was used for the production of bacterial cellulose (BC). The BC containing 5% and 10% ethanolic extract of Epilobium angustifolium (FEE) (BC...
Article
Full-text available
The potential of bacterial cellulose as a carrier for the transport of ibuprofen (a typical example of non-steroidal anti-inflammatory drugs) through the skin was investigated. Ibuprofen and its amino acid ester salts-loaded BC membranes were prepared through a simple methodology and characterized in terms of structure and morphology. Two salts of...
Article
Full-text available
The objective of this paper is to present the investigations of the heat transfer process carried out by means of the multi-ribbon mixer. It is shown that the heat transfer process for the synergic effect of the mixing process and the flowing liquid through the mixer has significantly higher values of the heat transfer coefficients than the mixer w...
Article
Full-text available
Since the effect of MFs (magnetic fields) on various biological systems has been studied, different results have been obtained from an insignificant effect of weak MFs on the disruption of the circadian clock system. On the other hand, magnetic fields, electromagnetic fields, or electric fields are used in medicine. The presented study was conducte...
Preprint
Here, we designed the composition of the coating of the paper sheets composed of chitosan, bacterial cellulose (nanofibres), and ZnO with boosted antibacterial and mechanical activity. We investigated the compositions with ZnO exhibiting two different sizes/shapes: (1) rods and (2) irregular sphere-like particles. The proposed processing of bacteri...
Preprint
The aim of this study was to demonstrate the applicability of a novel magnetically-assisted external-loop airlift bioreactor (EL-ALB), equipped with RMF generators for the preparation of Komagataeibacter xylinus inoculum during three-cycle repeated fed-batch cultures, further used for bacterial cellulose (BC) production. The fermentation carried ou...
Article
The study was aimed at investigating the heating efficiency of magnetically guided nanoparticles. The effect of graphene oxide (GO), magnetite (Fe3O4) and hybrid material (GO/Fe3O4) have been studied. The samples have been inductively heated at 42 °C in the presence of rotating magnetic field (RMF). The experiments have been conducted as a function...
Article
Application of electromagnetic field in biotechnological processes is considered a promising tool to enhance their effectiveness and to control microbe-derived synthesis of desired compounds. The current work analyzes impact of non-continuous rotating magnetic field (RMF) on ability of two Komagataeibacter xylinus strains to produce bacterial cellu...
Article
Full-text available
The cultivation of bacteria sets a ground for studying biological processes in many scientific disciplines. The development of the bacterial population is commonly described with three factors that can be used to evaluate culture conditions. However, selecting only one of them for the optimization protocol is rather problematic and may lead to unin...
Article
Full-text available
This study presents the procedure of deriving a compartmental model (CM) based on an analysis obtained from the computational fluid dynamics (CFD) model of a bioreactor. The CM is composed of two parts, a structural (that takes into account the architecture of the mathematical model), and a parametric part (which contains the extrinsic parameters o...
Article
Full-text available
Biotechnological processes involving the presence of microorganisms are realized by using various types of stirred tanks or laboratory-scale dual-impeller commercial bioreactor. Hydrodynamics and mass transfer rate are crucial parameters describing the functionality and efficiency of bioreactors. Both parameters strictly depend on mixing applied du...
Article
Full-text available
In this study, hexagonal boron nitride nanosheets enriched with hydroxyl groups (h-BN-OH) were successfully grafted on the surface of cellulose fibers after the simple and effective exfoliation and oxidation of bulk h-BN. OH groups of h-BN-OH and the ones presented on the surface of cellulose fibers interacted via hydrogen bonding. Both spectroscop...
Article
Full-text available
Increasing multidrug resistance has led to renewed interest in phage-based therapy. A combination of the bacteriophages and antibiotics presents a promising approach enhancing the phage therapy effectiveness. First, phage candidates for therapy should be deeply characterized. Here we characterize the bacteriophage vB_AbaP_AGC01 that poses antibacte...
Article
The emergence of multidrug-resistant (MDR) bacterial infections poses a catastrophic threat to medicine. The development of phage-based therapy combined with antibiotics might be an advantageous weapon in the arms race between human and MDR bacteria. A cocktail composed of the MDR Acinetobacter baumannii infecting bacteriophages with high lytic act...
Article
Full-text available
This study reports on research results in the field of the neutralization process (weak acid–strong base) under the action of a rotating magnetic field. The main objective of this paper is to present the possibilities of this process application to obtain the mixing time. The results show that the applied magnetic field had a strong influence on th...
Chapter
The chapter presents the methods of bacteriophage production with the application of the alternate magnetic field. Bacteriophages are viruses that can infect and destroy bacteria cells. Up to date, numerous types of phages have been discovered. Nevertheless, the basic mechanisms and properties are common. Nowadays, the growing interest of the appli...
Chapter
Full-text available
The effect of magnetic fields (MFs) on mammalian cells in vitro has been studied to clarify in greater details potential influence on biological systems. In spite of the numerous and valuable experiments, the MF molecular mechanisms that affect cells still remain unclear. Thus, the aim of the study was to evaluate the cellular response of L929 fibr...
Chapter
Full-text available
The chapter presents the experimental investigation of influence of the rotating magnetic field (RMF) on the hydrodynamic parameters and the oxygen mass transfer process in the novel construction external loop airlift reactor. The results show that the usage of RMF generator leads to the improvement of gas hold-up and the overall volumetric mass tr...
Article
Full-text available
Nowadays, an increasing amount of studies indicate the numerous applications of bacteriophages (e.g. medical, pharmaceutical, use in animal breeding, food processing). However, so far, there is limited availability of simple, efficient, and sensitive methods for evaluation and comparison of the phage’s lytic activity against its host. The aim of th...
Article
The aim of this study was to analyze the effects of a rotating magnetic field (RMF) on the activity and stability of horseradish peroxidase (HRP) and the catalyzed enzymatic process. It was found that 8 h of exposure to RMF does not influence the operational stability of HRP. At the same time, it was observed that the RMF improved HRP activity in a...
Article
This study reports a new multiphase apparatus, the external-loop airlift reactor (EL-ALR), with the RMF generators in the riser and downcomer columns, which shows the enhancement of hydrodynamic parameters (downcomer liquid velocity; mean liquid circulation velocity; mean circulation time and mixing time) in comparison to ALR without the applicatio...
Article
Full-text available
Bacterial cellulose spheres subjected to amination and inlaid modification with superparamagnetic molecules were analyzed with regard to possibility of their application as an immobilization carrier of Lecitase® Ultra (LU) enzyme. The starting point to obtain the carrier was synthesis of bacterial cellulose spheres performed in shaking cultures of...
Article
Full-text available
In this work, three-phase partitioning (TPP) was used for the purification of laccase from liquid cultures of Trametes versicolor. For determining the optimal conditions of TPP process, parameters such as initial pH (6.5, 7.0, 7.5, 8.0), ammonium sulphate saturation (20%-80%) and the water phase to tert-butanol ratio (1:0.5, 1:1, 1:2), were analyze...
Article
The study aimed to evaluate the influence of rotating magnetic field on the growth rate and cell metabolic activity of Gram-positive (Staphylococcus aureus, ATCC 43300, Enterococcus faecalis, ATCC 29212, Streptococcus mutans ATCC 35668) and Gram-negative bacteria (Escherichia coli ATCC 8739, Serratia marcescens ATCC 274, Klebsiella oxytoca PCM 22)....
Article
Bioethanol is a promising liquid biofuel, which can be produced from the wide range of biomass feedstock by the fermentation process with the Saccharomyces cerevisiae yeast. The application of the rotating magnetic field (RMF) is one of the possibilities to increase the efficiency of the process. Therefore, the magnetically-assisted bioreactor equi...
Article
Full-text available
Infective complications are a major factor contributing to wound chronicity and can be associated with significant morbidity or mortality. Wound bacteria are protected in biofilm communities and are highly resistant to immune system components and to antimicrobials used in wound therapy. There is an urgent medical need to more effectively eradicate...
Article
The usefulness of bacterial cellulose (BC), obtained from the cultures of Komagataeibacter xylinus exposed to rotating magnetic field (RMF), as a carrier for laccase immobilization was investigated in this study. It was found that the highest yield of laccase immobilization (>70%) was achieved in pH of 4.0 and this value was optimal in the case of...
Article
Full-text available
The aim of the study was to present an experimental investigation of the influence of the RMF on mixing time. The obtained results suggest that the homogenization time for the tested experimental set-up depending on the frequency of the RMF can be worked out by means of the relationship between the dimensionless mixing time number and the Reynolds...
Article
Full-text available
The main objective of these experiments was to study the oxygen mass transfer rate through the volumetric mass transfer coefficient (
Article
The mass transfer coefficient kL is a key parameter for an aeration mixing design and optimization. From the practical point of view, the volume-related liquid side mass transfer coefficient (kLa) is commonly applied in the gas-liquid contacting devices. This parameter is affected by several factors such as geometrical and operational characteristi...
Article
Many studies have focused on the possibility of applying graphene oxide as an effective drug delivery system, but also as an effective tool for a thermally-responsive system. Thus, the main aim of the study was to evaluate the cellular response of the MCF-7 cell line to covalently and non-covalently conjugated graphene oxide with hydroxycamptotheci...
Article
Full-text available
The aim of the present study was to evaluate the impact of a rotating magnetic field (RMF) on cellular and biochemical properties of Gluconacetobacter xylinus during the process of cellulose synthesis by these bacteria. The application of the RMF during bacterial cellulose (BC) production intensified the biochemical processes in G. xylinus as compa...
Article
Studies aimed at investigating factors and mechanism of induction of prophages, a major pathogenesis factor of Shiga toxin-producing Escherichia coli (STEC), are considered important to develop an effective treatment for STEC infections. In this study, we demonstrated the synergistic effect of the rotating magnetic field (RMF) of induction B = 34 m...
Article
Full-text available
The aim of the study was to analyze the changes in the parameters of bacterial cultures and bacterial cellulose (BC) synthesized by four reference strains of Gluconacetobacter xylinus during 31-day cultivation in stationary conditions. The study showed that the most visible changes in the analyzed parameters of BC, regardless of the bacterial strai...
Article
The study presents the results of an experimental analysis of the mixing process under the influence of a rotating magnetic field (RMF). Dimensionless correlations are proposed to predict the power consumption and mixing time for the analyzed mixing system. The results showed that the mixing behavior of the RMF mixer may be described by means of th...
Article
The main aim of the current study was to evaluate the usefulness of the two-dimensional correlation analysis (2DCorr) technique in assessing the physicochemical properties of bacterial cellulose (BC) depending on the synthesis time and Komagataeibacter xylinus strain used for its production. It was demonstrated that 2DCorr analysis allows to charac...
Article
The current study describes properties of bacterial cellulose (BC) obtained from Komagataeibacter xylinus cultures exposed to the rotating magnetic field (RMF) of 50 Hz frequency and magnetic induction of 34 mT for controlled time during 6 days of cultivation. The experiments were carried out in the customized RMF exposure system adapted for biolog...
Article
Full-text available