Uptake of Hydrocarbon by Pseudomonas fluorescens (P1) and Pseudomonas putida (K1) Strains in the Presence of Surfactants: A Cell Surface Modification

The objective of this research was the evaluation of the effects of exogenous added surfactants on hydrocarbon biodegradation and on cell surface properties. Crude oil hydrocarbons are often difficult to remove from the environment because of their insolubility in water. The addition of surfactants enhances the removal of hydrocarbons by raising the solubility of these compounds. These surfactants cause them to become more vulnerable to degradation, thereby facilitating transportation across the cell membrane. The obtained results showed that the microorganism consortia of bacteria are useful biological agents within environmental bioremediation. The most effective amongst all, as regards biodegradation, were the consortia of Pseudomonas spp. and Bacillus spp. strains. The results indicated that the natural surfactants (rhamnolipides and saponins) are more effective surfactants in hydrocarbon biodegradation as compared to Triton X-100. The addition of natural surfactants enhanced the removal of hydrocarbon and diesel oil from the environment. Very promising was the use of saponins as a surfactant in hydrocarbon biodegradation. This surfactant significantly increases the organic compound biodegradation. In the case of those surfactants that could be easily adsorbed on cells of strains (e.g., rhamnolipides), a change of hydrophobicity to ca. 30-40% was noted. As the final result, an increase in hydrocarbon biodegradation was observed.     

Assessment of the usefulness of particle size distribution measured by laser diffraction for soil water retention modelling

Particle size distribution (PSD) is a major soil characteristic, which is essential and commonly used for the development of pedotransfer functions (PTFs) to estimate the water retention of soils. The laser diffraction method (LDM) became a popular alternative to the standard sieve‐hydrometer method (SHM) of PSD measurement. Unfortunately, PSDs determined with LDM and SHM methods differ sometimes substantially. Moreover, it is claimed that the laser diffraction method underestimates finer fractions in favor of coarser fractions. Several authors have tried to elaborate on methods to recalculate LDM PSD into its SHM counterparts, but no universal methodology has been developed to this date. In this paper, we use PSD determined by LDM directly for PTF development and compare it with the classical PTF approach based on PSD measured by SHM. Four different PTF models based on LDM particle size distribution data were developed, with different PSD characteristics taken as the models' input variables. The possibility of using alternative PSD characteristics, such as deciles, area moment mean and volume moment mean, for PTF development was examined. The accuracy of PTF models constructed on the basis of LDM‐measured PSD was comparable with that of the developed models using texture data obtained from SHM, giving approximately the same RMSE and R² values. Our study shows that LDM‐measured particle size distribution may be directly used for PTF developments without any recalculations to their sieve‐hydrometer counterparts.     

Changes in selected hydrophobic components during composting of municipal solid wastes

Purpose

One of the most practical ways to utilise municipal solid waste is composting, thereby producing materials that may be productively used to improve soil properties. Wastes, as well as mature composts, contain hydrophobic substances, including fats, which are more resistant to microbiological decomposition than other constituents. The aim of this work was to determine qualitative and quantitative changes of hydrophobic substances, especially fatty acids, during the course of municipal solid waste composting. This provides new information on intensity of hydrophobic versus other substances decomposition undergoing during these processes.

Materials and methods

Raw materials, prepared according to MUT-DANO technology, were composted in a pile, and samples were taken after 1, 14, 28, 42, 56, 90 and 180 days of the composting. Temperature, moisture, total organic carbon, hydrophobic substances carbon (HSC) and fatty acid carbon (FAC) contents were determined in all samples. Hydrophobic substances were extracted with 1:2 (v/v) mixture of ethanol/benzene, while fats were extracted with petroleum ether and determined by GC analysis after transesterification with BF₃ in methanol.

Results and discussion

The HSC decreased from 27.8 to 9.3 g kg^?1 during first 90 days of composting, and thereafter remained constant. Similarly, the highest content of FAC was in raw compost, while the lowest was after 90 days. Octadecenoic acid predominated in the raw compost and decreased from 56 to 23 % FAC after 180 days. During the composting processes, domination of octadecenoic acid was replaced by hexadecanoic and octadecanoic acids, which increased from 18.8 to 36.7 % and 8.3 to 19.4 % FAC, respectively. The share of hexadecanoic, eicosanoic and docosanoic acids increased after the thermophilic phase. The presence of odd-numbered fatty acids (pentadecanoic and heptadecanoic) was noted, which are known to be products of the bacterial transformation-synthesis of lipid substances.

Conclusions

The extent of decomposition of hydrophobic substances, especially fatty acids, is greater than other components in composted municipal solid waste, and intensity of the biotransformation is significantly correlated with composting parameters, mainly temperature and time. During the thermophilic phase of municipal solid waste composting, the decrease in total content of hydrophobic substances is approximately fivefold, while the reduction in fatty acids can be about tenfold. Unsaturated fatty acids are more intensively decomposed during the composting processes, while saturated fatty acids are more resistant. Moreover, transformation of fatty matter may result in the creation of specific isomers with odd numbers of carbon atoms.     

Citrus flavanones: what is their role in cardiovascular protection?

Flavanones, including hesperidin and naringin, are polyphenolic compounds highly and almost exclusively present in citrus. Epidemiological studies reported an inverse relationship between their intake and the risk of cardiovascular diseases. Clinical and experimental data further showed their antihypertensive, lipid-lowering, insulin-sensitizing, antioxidative, and anti-inflammatory properties, which could explain their antiatherogenic action in animal models. Although flavanones may be promising compounds that are particularly active in cardiovascular disease prevention, clinical data are still scarce and most in vitro data have been obtained under nonphysiologically relevant conditions. Moreover, the mechanisms responsible for flavanone action are not fully elucidated. Therefore, further research is needed to better evaluate and understand the protective effects of flavanones in cardiovascular diseases.     

Mechanisms for Translocation of Heavy Metals from Soil to Epigeal Mosses

The mechanisms for translocation of heavy metals from soil to epigeal mosses were investigated. The first mechanism was demonstrated for ¹³⁷Cs and involved the uplifting of the pollutant-containing dust from the soil, followed by the local secondary deposition on surfaces of epigeal mosses and epiphytic lichens. The second mechanism involved the diffusion of metal cations from the soil through water wetting the moss into the gametophyte. The mechanism was demonstrated by measuring the electric conductance of wetted gametophytes with single ends immersed in solutions of Cu and Na salts. In addition, the concentrations of Cu and Cd were compared in moss samples exposed to the natural soil and to the soil contaminated with the metals. The exposition to the contaminated soil resulted in the statistically significant increase of metal concentrations in the gametophytes.     

Adsorption of Sodium Dodecylbenzenesulphonate (SDBS) on Candida maltosa EH 15 Strain: Influence on Cell Surface Hydrophobicity and n-alkanes Biodegradation

Water, Air, & Soil Pollution - The effect of exogenously added sodium dodecylbenzenesulphonate (SDBS) surfactant on biodegradation of a mixture of straight-chain aliphatic hydrocarbons...     

Food selection of burbot (Lota lota L.) larvae reared in illuminated net cages in mesotrophic Lake Maróz (north-eastern Poland)

Feeding and food selection of burbot (Lota lota L.) larvae reared in illuminated cages were studied. The experiment was carried out in mesotrophic Lake Maróz, in north-eastern Poland, for 6 weeks in two successive years. The initial stocking density was 1,250 larvae (20 DPH) per cage. Food selection according to the zooplankton groups (Rotifera, Cladocera and Copepoda) and length classes was expressed by the Strauss linear selectivity index (L). Zooplankton species composition in the lake was similar in the two seasons of the study and organisms shorter than 0.5 mm prevailed in the plankton. The mean number of prey found in burbot alimentary tracts increased from about 40 up to over 200 during the course of the study. A very large inter-individual variation in the amount of food organisms consumed by fish was noted. Analysis of the values of the Strauss food selectivity index shows that at the beginning of the first year of the experiment, burbot larvae preferred copepods, most numerous in the environment at that time; later, fish tended to select cladocerans. In the second year of the study, fish more often ate copepods, irrespective of their quantities in the environment. During the whole study, reared burbot larvae did not eat rotifers, even when they were numerous in cages. Similarly to the rotifers, the smallest planktonic organisms, measuring up to 0.5 mm in length, were typically neglected by fish, while the 0.6–1.0 mm group was most frequently selected. There were also considerable individual differences between particular burbot specimens in their food preferences.     

Determination of elements removal in different harvesting scenarios of Scots pine (Pinus sylvestris L.) stands

Increasing demand for renewable energy and limiting CO₂ emissions have stimulated much interest in wood-based biofuels. Unfortunately, expanding the utilization of forest biomass may cause nutrient depletion in forested environments. This study investigates the element content from various parts of the tree. Comparisons were made between different harvesting scenarios and their impact on the amount of nutrients removed from the forest environment. The harvesting scenarios were: stem-only harvesting (SOH), branch and stem harvesting (BSH), and two variants of whole-tree harvesting (WTH). The elements taken into account were: carbon (C), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), sulphur (S), copper (Cu), iron (Fe), nickel (Ni), manganese (Mn), zinc (Zn), cadmium (Cd), chromium (Cr) and lead (Pb). To make the results comparable, the same amount of removed biomass was taken into calculation. The differences between harvesting scenarios were significant. The amounts of removed elements formed similar pattern: the lowest level was found in SOH, average in BSH, and highest in both variants of WTH. This confirms that the application of WTH is connected with increased risk of nutrient depletion, even when the volume of harvest would be equal to other variants.     

Changes in soil morphology of Podzols affected by alkaline fly ash blown out from the dumping site of an electric power plant

Purpose

The impacts of fly ash on the chemistry of forest floors were previously described in literature, while impacts on soil properties were less recognised. Soil investigations were focussed mainly on increases of pH and base saturations in surface horizons. The purpose of this study was to describe the influence of alkaline fly ash blown out from the dumping site of a lignite-fired power plant on pH changes of ectohumus horizons of Podzols and the morphology of deeper horizons.

Materials and methods

We investigated the soil profiles of Podzols derived from loose quartz sand and developed under pine forest surrounding the dumping site of the power plant Be?chatów, central Poland. In the vicinity of the fly ash dumping site, five Podzol profiles located at a distance of 50 m from the dumping site were investigated, as well as soil profiles located along the transect set at distances of 50, 300, 800 and 2000 m from the dumping site. Control profiles were located at a distance of 7.3 km from the dumping site. Soil morphology was described in the field and the following properties were determined: soil texture, hydrolytic acidity, exchangeable cations, total organic carbon and total nitrogen content.

Results and discussion

The pH values of Podzol ectohumus horizons located close to the dumping site ranged from 6.01 to 7.34 compared to a range of 3.08–3.72 in the control. Ectohumus horizon located 300 m from the dumping site showed a pH range of 4.13–4.26, while at a distance of 800 m, the pH values did not differ from those of the control site. The upper part of the eluvial soil horizons located close to the dumping site had been transformed into transitional AE horizons in which humic substances translocated from ectohumus horizons were accumulated. Moreover, the organic carbon content of this horizon increased compared to the carbon content of the illuvial Bs horizon located below it. Under the influence of alkalisation of upper horizons, the illuvial Bhs horizons vanished and were transformed into Bs horizons.

Conclusions

Changes in soils affected by fly ashes are connected with alkalinisation of ectohumus horizons. Podzolisation processes can be reduced or even completely stopped regarding the distance from the dumping site. Eluvial Podzol horizons located close to the dumping site may be transformed into AE horizons in which humic substances translocated from ectohumus horizons are accumulated. Due to transformation and translocation of organic components, Bhs horizons can be transformed into Bs horizons.

     

Apple polyphenols and fibers attenuate atherosclerosis in apolipoprotein E-deficient mice

Atherosclerosis, which is closely linked to nutritional habits, is a major cause of mortality in Western countries. Most of the previous investigations carried out on health effects of apples have been focused on their capacity to lower lipid concentration as well as on their antioxidant effects. The aim of the present study was to investigate the antiatherosclerotic effects of apple polyphenols and fibers. A crude apple polyphenol extract and low-viscosity apple fibers isolated from cider apples were administered separately or in association with the diet of apo E-deficient mice. After 4 months of supplementation, lipemia and oxidative stress biomarkers were measured and atheroslerotic lesions assessed by histomorphometry. Total plasmatic cholesterol and triacylgycerol levels were not affected by supplementation, and hepatic cholesterol level was lower in the group supplemented with both fibers and polyphenols. Uric acid concentrations and antioxidant capacity (FRAP) in plasma were reduced in all groups supplemented with polyphenols or fibers. The mean lesion area was reduced by 17, 38, and 38%, respectively, for the polyphenol, fiber, and polyphenol + fiber groups. Apple constituents supplied at nutritional doses therefore limit the development of atherosclerotic lesions in the aorta of apo E-deficient mice. On the basis of the results, we hypothesize that apple fibers and polyphenols may play a role in preventing atherosclerosis disease by decreasing uric acid plasma level.