Kinetics of styrene biodegradation by Pseudomonas sp. E-93486

The research into kinetics of styrene biodegradation by bacterial strain Pseudomonas sp. E-93486 coming from VTT Culture Collection (Finland) was presented in this work. Microbial growth tests in the presence of styrene as the sole carbon and energy source were performed both in batch and continuous cultures. Batch experiments were conducted for initial concentration of styrene in the liquid phase changed in the range of 5–90 gm−3. The Haldane model was found to be the best to fit the kinetic data, and the estimated constants of the equation were: μm= 0.1188 h−1, KS=5.984 mg l−1, and Ki=156.6 mg l−1. The yield coefficient mean value Yapp xs for the batch culture was 0.72 gdry cells weight(gsubstrate)−1. The experiments conducted in a chemostat at various dilution rates (D=0.035–0.1 h−1) made it possible to determine the value of the coefficient for maintenance metabolism md=0.0165 h−1 and the maximum yield coefficient value YM xs ¼ 0:913. Chemostatexperiments confirmed the high value of yield coefficient Yapp xs observed in the batch culture. The conducted experiments showed high activity of the examined strain in the styrene biodegradation process and a relatively low sensitivity to inhibition of its growth at higher concentrations of styrene in the solution. Such exceptional features of Pseudomonas sp. E-93486 make this bacterial strain the perfect candidate for technical applications

Enzymes involved in vinyl acetate decomposition by Pseudomonas fluorescens PCM 2123 strain

Esterases are widely used in food processing industry, but there is little information concerning enzymes involved in decompositions of esters contributing to pollution of environment. Vinyl acetate (an ester of vinyl alcohol and acetic acid) is a representative of volatile organic compounds (VOCs) in decomposition, of which hydrolyses and oxidoreductases are mainly involved. Their activities under periodically changing conditions of environment are essential for the removal of dangerous VOCs. Esterase and alcohol/aldehyde dehydrogenase activities were determined in crude cell extract from Pseudomonas fluorescens PMC 2123 after vinyl acetate induction. All examined enzymes exhibit their highest activity at 30–35 °C and pH 7.0–7.5. Esterase preferably hydrolyzed ester bonds with short fatty chains without plain differences for C2 or C4. Comparison of Km values for alcohol and aldehyde dehydrogenases for acetaldehyde suggested that this metabolite was preferentially oxidized than reduced. Activity of alcohol dehydrogenase reducing acetaldehyde to ethanol suggested that one mechanism of defense against the elevated concentration of toxic acetaldehyde could be its temporary reduction to ethanol. Esterase activity was inhibited by phenylmethanesulfonyl fluoride, while β-mercaptoethanol, dithiothreitol, and ethylenediaminetetraacetic acid had no inhibitor effect. From among metal ions, only Mg2+ and Fe2+ stimulated the cleavage of ester bond

Kinetics of vinyl acetate biodegradation by Pseudomonas fluorescens PCM 2123

The microbial degradation of vinyl acetate (VA) by Pseudomonas fluorescens PCM 2123 strain was studied in both batch and continuous modes. The purpose of the experiments was to determine the kinetic model of the cell growth and biodegradation rate of vinyl acetate (VA), which was the sole carbon and energy source for tested microorganisms. The experiments, carried out in a batch reactor for several initial concentrations of growth substrate in the liquid phase ranging from 18.6 to 373 gsubstrate·m–3 (gs·m–3) made it possible to choose the kinetic model and to estimate its constants. The Haldane inhibitory model with the values of constants: μm = 0.1202 h–1, KS = 17.195 gs·m–3, Ki = 166.88 gs·m–3 predicted the experimental data with the best accuracy. To set the parameters of maintenance metabolism it was necessary to carry out a series of continuous cultures at different dilution rates (0.05 to 0.072 h–1) and concentrations of VA in the liquid supplied to the chemostat ranging from 30.9 to 123.6 gs·m–3. The obtained data-base enabled to determine the coefficient for maintenance metabolism (me = 0.0251 gsubstrate·gcell dry weight –1·h–1 (gs·gcdw –1·h–1)) as well as the maximal and observed values of yield coefficients, Yxs M = 0.463 gcdw·gs –1 and (Yxs)obs = 0.411 gcdw·gs –1, respectively. The developed kinetics was verified by comparison of the computed and obtained in batch experiments profiles of changes in biomass and growth substrate concentrations

Influence of metabolic risk factors of cardiovascular diseases on cognitive impairment in elderly patients

Wstęp. Zaburzenia funkcji poznawczych występujące u osób starszych obniżają jakość życia i wpływają na stan zdrowia tych pacjentów. Celem pracy jest ocena zaburzeń poznawczych u osób starszych, ustalenie związku między stopniem tych zaburzeń i metabolicznymi czynnikami ryzyka chorób sercowo-naczyniowych. Materiał i metody. U 93 starszych pacjentów przeprowadzono test MMSE, na podstawie którego utworzono następujące grupy: 1 &#8212; kontrolna (bez zaburzeń poznawczych), 2 &#8212; pacjenci z zaburzeniami poznawczymi oraz podgrupy: 2a &#8212; osoby z łagodnymi zaburzeniami, 2b &#8212; chorzy z zaburzeniami średniozaawansowanymi i głębokimi. Oceniono zależność pomiędzy stopniem zaburzeń poznawczych i stężeniem frakcji lipidowych. Na podstawie kryteriów klinicznych, takich jak: I &#8212; obecność cukrzycy, II &#8212; zwężenia tętnic szyjnych > 50%, III &#8212; współistnienie obu tych czynników, IV &#8212; występowanie zespołu metabolicznego, wyodrębniono 4 grupy. Wyniki. Uzyskano dodatnią korelację MMSE i stężenia cholesterolu frakcji HDL (HDL-C), ujemną korelację: MMSE i LDL/HDL, brak korelacji: MMSE i stężenia cholesterolu całkowitego (TC), cholesterolu frakcji LDL (LDL-C) i triglicerydów (TG), istotne różnice stężeń frakcji lipidowych TG, HDL-C i LDL/HDL pomiędzy grupą 1 i 2; różnice te zwiększają się przy porównaniu grupy 1 i podgrupy 2b. Uzyskano niższy wynik MMSE u chorych na cukrzycę i u pacjentów z zaawansowanymi zmianami w tętnicach szyjnych; wartość ta jest jeszcze mniejsza, jeśli oba stany współistnieją. Zespół metaboliczny wiąże się z istotnie niższym wynikiem MMSE (p < 0,0004). Wnioski. Zaburzeniom poznawczym i otępieniu u osób w podeszłym wieku towarzyszy niskie stężenie cholesterolu frakcji HDL, wysoka wartość wskaźnika LDL/HDL oraz wysokie stężenie TG. Stężenie cholesterolu frakcji HDL koreluje dodatnio, a wartość LDL/HDL ujemnie ze stopniem zaburzeń poznawczych. Zmiany miażdżycowe bez istotnego zwężenia tętnic szyjnych nie wpływają na funkcje poznawcze pacjentów. Zaburzenia poznawcze są większe u chorych na cukrzycę typu 2, z zaawansowanymi zmianami tętnic szyjnych i pogłębiają się przy współistnieniu obu stanów. Zespół metaboliczny wiąże się z bardzo wysokim ryzykiem osłabienia funkcji poznawczych.Background. Cognitive impairment in older people diminishes their quality of life and interferes with their state of health. The aim of the study is the assessment of cognitive functions in elderly people, the evaluation of the correlation between cognitive impairment and metabolic risk factors of cardiovascular diseases. Material and methods. 93 patients over 60 years old completed the Mini-Mental State Examination (MMSE), as a consequence, the following the groups were established: Group 1 &#8212; control group without cognitive impairment, group 2 &#8212; presence of cognitive impairment: 2a &#8212; mild impairment, 2b &#8212; moderate or severe dementia. The interdependence of the MMSE score and serum concentration of fractionated lipids was evaluated, and it was examined whether cognitive impairment was connected with diabetes type 2, carotid arteries stenosis or with the coexistence of the first two and finally with the metabolic syndrome. Results. The following results were obtained: a positive correlation between MMSE score and HDL-C concentration, negative correlation between MMSE score and LDL/HDL index, no correlation between MMSE score and TC, LDL-C and TG concentration. In patients of group 2, the HDL-C concentration was significantly lower, the TG concentration higher, and the LDL/HDL index was higher than in group 1, these tendencies increased when both groups, 1 and 2b were compared. In patients with diabetes or with carotid stenosis, the MMSE score was low, the results decreased in patients with the coexistence of both. Patients with metabolic syndrome revealed significantly lower MMSE scores compared to patients without the syndrome (p < 0.0004). Conclusion. Low HDL-C concentration, high value of LDL/HDL coefficient and high TG concentration are connected with cognitive impairment in elderly people. HDL-C concentrations correlate positively, and values of LDL/HDL coefficients correlate negatively, with the degree of cognitive dysfunction. Cognitive impairment is connected with diabetes type 2 and carotid stenosis, and it intensifies in patients suffering from both. Metabolic syndrome gives a very high risk of cognitive impairment

A comparative study of biodegradation of vinyl acetate by environmental strains

Four Gram-negative strains, E3_2001, EC1_2004, EC3_3502 and EC2_3502, previously isolated from soil samples, were subjected to comparative studies in order to select the best vinyl acetate degrader for waste gas treatment. Comparison of biochemical and physiological tests as well as the results of fatty acids analyses were comparable with the results of 16S rRNA gene sequence analyses. The isolated strains were identified as Pseudomonas putida EC3_2001, Pseudomonas putida EC1_2004, Achromobacter xylosoxidans EC3_3502 and Agrobacterium sp. EC2_3502 strains. Two additional strains, Pseudomonas fluorescens PCM 2123 and Stenotrophomonas malthophilia KB2, were used as controls. All described strains were able to use vinyl acetate as the only source of carbon and energy under aerobic as well as oxygen deficiency conditions. Esterase, alcohol dehydrogenase and aldehyde dehydrogenase were involved in vinyl acetate decomposition under aerobic conditions. Shorter degradation times of vinyl acetate were associated with accumulation of acetic acid, acetaldehyde and ethanol as intermediates in the culture fluids of EC3_2001 and KB2 strains. Complete aerobic degradation of vinyl acetate combined with a low increase in biomass was observed for EC3_2001 and EC1_2004 strains. In conclusion, P. putida EC1_2004 is proposed as the best vinyl acetate degrader for future waste gas treatment in trickle-bed bioreactors

Zróżnicowanie mieszanych populacji mikroorganizmów po skriningu w obecności wybranych lotnych związków organicznych

Biological methods of productive gases treatment from Volatile Organic Compounds are based on the catalytic activities of degradative enzymes from environmental microorganisms. That is why screening for microorganisms able to degrade xenobiotics is performed. In order to isolate microorganisms able do degrade selected VOCs (vinyl acetate and styrene), soil sampling was performed in the area of Synthos S.A. in Oswiecim (Poland) (formerly Chemical Company “Dwory” S.A.) in August 2006. Two independent localizations were chosen for the collection of samples, and they were the outlet of gases arising during polymerisation of polyvinyl acetate and polystyrene. Different selection media were applied. They consisted of mineral salts solution, buffer components, and selective factor. As the selective factor increasing concentrations (50÷4000 mg/dm3) of vinyl acetate or constant concentration of styrene (100 mg/dm3) were applied. There was no increase of styrene concentration due to the significant drop in the amount of mixed population of microorganisms after application of that selective factor. Isolation, determination of microorganisms’ amount on the grounds of colony morphology and results of the Gram staining of cells, were carried out after introduction of vinyl acetate in the concentrations of 1500, 2000, 2500, 3000 and 3500 mg/dm3, and at the end of 6 weeks adaptation to styrene. Presence of selected VOCs caused significant changes in the amount and composition of mixed population of microorganisms. Both, vinyl acetate and styrene, resulted in the decrease of the initial number of populations. The ratio of Gram-negative to Gram-positive cells was changing in the presence of selected VOCs. In the beginning Gram-negative bacteria predominated. Increasing concentrations of vinyl acetate brought about gradual decrease in the number of Grampositive bacteria, and finally after application of 3000 mg/dm3 of vinyl acetate mixed populations consisted of only Gram-negative bacteria. Different chemical structure of styrene probably caused almost complete decay of Gramnegative bacteria in the presence of that selective factor. Differences in the structure of the bacterial cell envelopes are most likely the reason of increased survivability of Gram-positive bacteria, mainly filiform cells of Actinomycetes