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The potential of Stenotrophomonas maltophilia KB2 for phenol degradation under exposure to heavy metal

Gąszczak Agnieszka, Szczyrba Elżbieta, Szczotka Anna

Chemical and Process Engineering : New Frontiers

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2024

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Vol. 45, nr 2

art. no. e64

EN

The large diversity of chemical substances present in air, water, or soil makes it necessary tostudy their mutual impact on the effectiveness of microbiological decomposition ofcontaminants. This publication presents the results of the studies aimed at evaluating the effect of two biogenic heavy metals - zinc and copper - on the phenol biodegradation by the Stenotrophomonas maltophilia KB2 strain. The tests were carried out for concentrations ofmetals significantly exceeding the legally permitted wastewater values: for zinc up to13.3 g·m -3, and copper up to 3.33 g·m -3. In the tested metal concentration range, phenol biodegradation by the S. maltophilia KB2 strain was not significantly influenced by theintroduced dose of zinc. While the presence of copper inhibited both biomass growth andsubstrate degradation. Kinetic data of metal and phenol mixtures were analyzed and very goodcorrelations were obtained for the proposed equations. An equation consistents with the Hanand Levenspiel model was proposed for the system S. maltophilia KB2-phenol-copper, whilean equation consistents with the Kai model for the system St. maltophilia KB2-phenol-zinc. The simultaneous presence of Zn and Cu ions in the culture resulted in a stronger inhibition ofphenol biodegradation.

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Biodegradacja tworzyw sztucznych w obecności szczepów bakteryjnych wyizolowanych z terenów sąsiadujących z zakładami petrochemicznymi

Szczyrba Elżbieta, Gąszczak Agnieszka, Szczotka Anna, Pokynbroda Tetiana, Koretska Nataliia

Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk

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2023

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Nr 27

105--122

PL

W pracy opisano biodegradację folii LDPE w obecności nowych szczepów bakteryjnych wyizolowanych z terenów zanieczyszczonych przez przemysł petrochemii czny. Proces degradacji polimerów przez mikroorganizmy został potwierdzony poprzez zastosowanie różnych technik badań m.in.: określenie zmiany masy polimeru, spektroskopię podczerwieni FTIR i pomiar kąta zwilżania.

EN

Nowadays, plastics are widely used in all aspects of life. This is related to their physicochemical properties, high strength, durability, and low production costs. An alternative to conventional plastic waste management methods is environmentally friendly biodegradation. The importance of microorganisms in the biodegradation of plastics cannot be overstated. Bacteria, the most common organisms on Earth, are capable of surviving in various, even extreme, natural conditions. Hydrocarbon-degrading bacteria are believed to be an important factor in the formation of biofilm on the surface of petroleum-based polymers. The degradation of plastics occurs due to the metabolism of these bacteria, which can utilize hydrophobic hydrocarbons as a source of carbon and energy. Bacteria capable of breaking down aromatic hydrocarbons, such as benzene and styrene, have been isolated from soil samples taken near industrial plants. For further research, we selected strains OR13, OR23.1, and OR23.2, which exhibited the fastest styrene decomposition and the most intense biomass growth. The isolated strains showed morphological and biochemical diversity. The biodegradation of LDPE by strains OR13, OR23.1, and OR23.2 was assessed by measuring changes in film mass after incubation in bacterial cultures. The OR23.1 strain exhibited the highest biodegradation efficiency of LDPE at 1.49%. The biodegradation of LDPE by strains OR13, OR23.1, and OR23.2 was assessed by measuring changes in film mass after incubation in bacterial cultures. The OR23.1 strain exhibited the highest biodegradation efficiency of LDPE at 1.49%. The polyethylene films for strains OR13 and OR23.2 exhibited 1.29%, and 1.11% degradation efficiencies, respectively. The control sample did not experience a decrease in biomass. It has been established that the products of polyethylene biodegradation are safe for wheat, as their toxicity level did not exceed 20% for the tested strains. The experiments demonstrated that the tested strains affect the hydrophobicity of LDPE, increasing its sensitivity to biodegradation. The OR13 strain had the greatest impact, resulting in the largest decrease in contact angle when interacting with the polyethylene foil. Fourier-transform infrared spectroscopy (FTIR) showed changes in peak size and functional groups, confirming the modification of the polymer surface after biological treatment. The strains OR13, OR23.1, and OR23.2 were found to increase the carbonyl index of the biodegraded film. This is probably due to the biological activity of the microorganisms, which leads to the formation of new ketone or aldehyde C=O groups and indicates a higher degree of polymer oxidation.

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Mikrobiologiczna degradacja tworzyw sztucznych

Szczyrba Elżbieta, Gąszczak Agnieszka, Szczotka Anna, Pokynbroda Tetiana

Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk

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2022

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nr 26

49--71

PL

W pracy poruszono zagadnienia związane z biodegradacją tworzyw sztucznych, których usuwanie ze środowiska naturalnego stało się ogromnym wyzwaniem. Opisano proces degradacji polimerów przez mikroorganizmy oraz przedstawiono podstawowe techniki badań pozwalające na zbadanie stopnia rozkładu tworzyw sztucznych.

EN

Plastics are long chain synthetic polymers produced based on fossil fuels such as oil and natural gas. Due to their properties, like lightness, durability, strength, flexibility, and low production costs, they have become indispensable in everyday life. Every year, the amount of polymers produced increases, in 2020 only in Europe 49.1 million tonnes of polymers were produced. With the increasing production of plastics and their widespread use, a global problem with the accumulation of waste in the natural environment has arisen. In Europe, synthetic waste is mostly incinerated (42.6%) and recycled (34.6%). In the natural environment, plastics can be degraded both by abiotic processes and by biodegradation (Fig.5.). The susceptibility to degradation of polymers depends on their physicochemical properties, the length of the polymer chain, and their composition. Long-chain polymers containing only carbon, such as polyethylene and polypropylene, are more resistant to degradation, while in the case of polyurethane and polyethylene terephthalate, the presence of heteroatoms in the chain, e.g. oxygen, causes greater susceptibility to biodegradation. The appearance of polymer waste in the natural environment caused many microorganisms to develop the ability to use plastics as a source of carbon and energy. The evolution of the metabolic systems of cells, which allows obtaining nutrients from polymers, somehow adapts microbes to live in the era of synthetic materials. Microorganisms equipped with the ability to degrade plastic have been characterized in many scientific studies (Tab. 2). The biodegradation of plastics is a complex process that depends on several factors: substrate availability, surface characteristics, morphology, and molecular weight. The first stage of biodegradation is the deposition of microorganisms on the surface of the polymer, which is largely influenced by the hydrophobicity / hydrophilicity of the material. Microorganisms then produce specific extracellular enzymes that break down the main polymer chain into smaller fragments – dimers and monomers. Then the polymer molecules are transported inside the cell and the final products of polymer decomposition are water, CO2, and biomass. Plastics are characterized by high durability and resistance to biodegradation, therefore pre-aging or pre-treatment of synthetic materials is often necessary. The purpose of these treatments is to modify the surface, which increases susceptibility to the action of enzymes secreted by microorganisms. The most commonly used pre-treatment techniques are UV, gamma, high temperature, and nitric acid treatment. These techniques either reduce hydrophobicity or introduce more biodegradable groups on the surface of the polymer. Describing the process of biodegradation of plastics is a technical challenge because it is a long-term process and difficult to study. The most commonly used methods of assessing the biodegradation of a polymer are the examination of the amount of mass lost by polymers, the examination of hydrophobicity and surface changes by imaging techniques such as SEM, and the chemical composition of polymers using Fourier transform infrared spectroscopy.

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Jaki wpływ mają nanocząstki tlenku niklu na wzrost szczepu Stenotrophomonas maltophilia KB2 w obecności fenolu?

Gąszczak Agnieszka, Szczyrba Elżbieta, Szczotka Anna, Kolarczyk Hanna, Sołtys Elżbieta, Janus Bożena

Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk

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2021

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nr 25

57--74

PL

Wprowadzenie do hodowli szczepu St. maltophilia KB2 nanocząstek tlenku niklu nie zahamowało procesu biodegradacji fenolu, a reakcja populacji bakterii była uzależniona od stężenia nanocząstek i użytego surfaktantu. Opracowano metodykę przygotowania stabilnej dyspersji badanych nanocząstek oraz oceniono wpływ wybranych surfaktantów na wzrost komórek szczepu St. maltophilia KB2.

EN

The introduction of nickel oxide nanoparticles into the St. maltophilia KB2 cultures did not inhibit the phenol biodegradation process, and the reactions of the bacterial population were depended on the nanoparticles concentrations and the surfactant used. The methodology for the preparation of the tested nanoparticles stable dispersion was developed and the influence of selected surfactants on the growth of St. maltophilia KB2 cells was assessed.

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Wpływ niklu na wzrost szczepu stenotrophomonas maltolphilia KB2 w obecności fenolu

Szczyrba Elżbieta, Gąszczak Agnieszka, Szczotka Anna, Kolarczyk Hanna, Janus Bożena

Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk

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2020

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nr 24

95--105

PL

Wykonano eksperymenty mające na celu zbadanie wzrostu komórek szczepu KB2 w obecności niklu, przy zastosowaniu fenolu jako źródła węgla i energii. Przeprowadzane badania potwierdziły hamujący wpływ niklu na wzrost badanego szczepu nawet dla niskich stężeń tego metalu.

EN

The influence of nickel on the growth of KB2 strain was tested for different concentrations of metal in the presence of phenol as the sole carbon and energy source. The inhibition effect of nickel on bacterial growth was confirmed even for low concentration of tested metal.