Agnieszka Gąszczak, Grażyna Bartelmus, Izabela Greń and Daniel Janecki
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.
One of the methods for recovery and utilization of waste products from the poultry industry is to subject them to the methane fermentation process in the biogas plant. These are waste with a high content of fatty compounds and proteins, including keratin. Their specificity is characterized by rapid possibility of spoilage, rancidity and problems of further management. These wastes are characterized by varying degrees of complexity, thus their use as a raw material for the biogas fermenter should be preceded by a pre-treatment. An example of waste generated in poultry processing is biological sludge. Optimizing this material with highly enzymatic fungi could accelerate the degradation of the organic matter contained and, as a result, increase the energy efficiency of this type of waste. Quantitative and qualitative parameters of biogas produced from biological sludge processed by isolated filamentous fungi with high metabolic potential were determined. Laboratory tests were based on the modified methodology included in the standards DIN 38414-S8 and VDI 4630. Based on the results obtained, it was found that the pre-optimization of biological sludge by fungal strains with different metabolic potential, influences on the yield of biogas production, including methane. There was an increase in the biogas yield from the biological sludge processed by the mixed fungal consortium (by 20 %) and the strain marked as F1 (by 14 %) as compared to the non-inoculated material, which was also reflected in the amount of methane produced in the case of the mixed fungal consortium (by 28 %) and the strain marked as F1 (by 12 %).
Joan S. Adriano, Glenn G. Oyong, Esperanza C. Cabrera and Jose Isagani B. Janairo
The field of microbial biotechnology has revolutionized the utilization of microorganisms to overcome the problems of environmental pollutions. The present study aimed to identify silver-tolerant isolates and screen their ability to synthesize silver nanoparticles for possible use as bioremediation agents. Seventeen bacterial isolates from soil collected from the Smokey Mountain landfill in Manila, Philippines, were found to tolerate 0.01 M AgNO3 in the culture medium. Molecular and phylogenetic analyses using the 16S rRNA gene sequence identified the isolates as Bacillus cereus, Bacillus subtilis, Bacillus flexus, Bacillus thuringiensis, Alcaligenes faecalis, Achromobacter sp. and Ochrobactrum sp. The formation of silver nanoparticles was evident in the change in color of the reaction mixtures, and was detected through UV-VIS spectroscopy with absorbance peaks at 250-300 nm and 400-450 nm. Scanning electron microscopy revealed the aggregation of diverse shapes of silver nanoparticles with sizes ranging from 70 to 200 nm. The best silver nanoparticle-synthesizing isolates were Alcaligenes faecalis and Bacillus cereus. The results denote the promising microbial technology application of the 17 silver-tolerant isolates in combating the adverse effects of metals and other pollutants in the environment.
Variations in immission fields resulting from emissions and pollutant dispersion in the atmosphere were investigated. The analysis was based on data from the four-year period covering the years 2012-2015, collected in two automatic atmospheric air monitoring stations, one located in Germany in Magdeburg which is the capital of Saxony-Anhalt and the other in Poland in Lodz, i.e. the seat of Lodz Region authorities. Selected immission monitoring stations in both cities are located in the areas with similar urban development and are characterized by high levels of pedestrian and car traffic. In both measuring stations the following atmospheric air pollutants were measured: PM10, sulfur dioxide, nitrogen oxide and nitrogen dioxide, and ozone (carbon monoxide was analyzed only for the station located in Lodz). On the basis of the measured data the periodic exceedance of air pollution limit values measured at both monitoring stations were observed, as well as the levels of particular pollutants and changes in immission fields were analyzed. It seems that this information may be useful not only to the competent authorities of the country but also to the users of these areas.
Various techniques of determination of properties of physicochemical processes of heavy metal sorption in biosorbents were analysed. The methods of preparing and storing samples, conditions of experiment performance, as well as the methods of data interpretation were discussed. Two procedures of study were analysed: (1) in the static system of biosorbent-solution contact and (2) in the system of dynamic flow of solution. Copper cation sorption was studied. The effect of consecutive stages of the study on the quality of final results was shown. A high degree of uncertainty of the sorption capacity assessment was reported, which was dependent on the manner of conducting the study. The application of the pseudo-second order reaction model was substantiated to describe kinetics of cation-exchange sorption and the model of Langmuir isotherm to describe equilibria. The study conducted reveals that in order to perform comparative analyses, it is necessary to establish a joint concept of conducting studies and the interpretation of results.
The article presents the results of life cycle assessment of different scenarios of biomass use to produce energy in a selected company. The study is made on the case of Lesaffre Polska S.A. and its facility in Wolczyn which is one of the most modern biomass plants in Central Europe. The company is one of the leaders of using the environmental criteria in its strategic decision-making. Its goal is to avoid any waste and to form its own circular business system. One of its recent investments is a biomass fired steam boiler that uses agricultural and woody biomass to produce energy. Previously, biomass was sold to power plant and co-fired with coal. The scope of the paper is to assess the actual change in the environmental impact of biomass use in the Wolczyn facility. For that purpose, the life cycle assessment is used with the ReCiPe endpoint indicator. The assessment is based on the comparison of two scenarios: one assuming the biomass combustion in a new boiler, and the second one, assuming co-firing biomass with coal. The results of the study show that the investment is making a significant difference as far as the overall environmental impact is. Through avoiding the co-firing related emissions the company makes a big step ahead towards the decrease of their environmental impacts. The analysis shows that the significant impact in the co-firing scenario is posed in such categories as fossil depletion, climate change with impacts on human health and on ecosystems, particulate matter formation and agricultural land occupation. In the biomass combustion scenario, the above categories are complemented with metal depletion, natural land transformation, urban land occupation and human toxicity categories but with 4 times decrease of the overall impact. The study also shows that the change of the combustion system makes the most significant difference, while all the other factors, like biomass cultivation and processing, biomass transport have much lesser impact.
Justyna Grzelak, Radosław Ślęzak, Liliana Krzystek and Stanisław Ledakowicz
The aim of this study was to investigate the effect of pH on the dark fermentation process of kitchen waste by specifying the composition of the volatile fatty acids (VFA), H2 and by drawing the carbon balance. Studies were carried out in 8 dm3 batch bioreactor in mesophilic conditions. The kitchen waste from the city of Lodz were used as a substrate. Based on the study, it was observed that most of the VFA was produced during the first two days of the process, while in the following days the production was diminished. The highest production of VFA (19.5 g/dm3) was obtained in the bioreactor, where the pH was 7 and 8. Analyzing the produced VFA it was observed that mostly the acetic and butyric acid had been produced. Most of acetic acid (over 70 %) was obtained in fermenter with pH 7 and 8. In contrast, most of the butyric acid (over 40 %) was in the bioreactor with a pH of 6. Production of H2 was in the range from 4.29 to 26.5 dm3, wherein the largest amount of H2 was created in the bioreactor with a pH of 6.
Małgorzata Nabrdalik, Ewa Moliszewska and Sławomir Wierzba
Antagonistic activity of microorganisms against phytopathogens is mainly the results of plants’ health improvement due to the inhibition of pathogens growth and the induction of plants resistance against diseases. The aim of the research was to determine antagonistic properties of Pantoea agglomerans against Rhizoctonia solani. The properties of two strains P. agglomerans BC17 and BC45 were assessed according to the following criteria: mycelial growth of R. solani in the presence of bacterial metabolites, an impact of P. agglomerans on the growth of sugar beet in the pots containing soil with and addition of R. solani and without it, the ability to produce indole-3-acetic acid (IAA). It has been recorded that antagonistic properties of tested strains are different. In the presence of metabolites of BC17 strains, the mycelial growth of R. solani was inhibited by 78 % and for the strain BC45 the value amounted 46 %. In the pot bioassay the number of infested plants growing in the soil inoculated with P. agglomerans and the pathogen was lower when compared with the pots containing R solani. A higher reduction of infested plants, amounting 23 %, was obtained for the strain BC17. Both strains had the ability to produce IAA - a plant hormone of the auxin class, in the presence of tryptophan and its absence in the medium. The highest concentration of IAA was recorded after 7 days of culturing in the supernatant obtained from the media containing 2000 μg/cm3 of tryptophan. For the strain BC17 the concentration of IAA marked in the post - culturing liquid amounted 71.57 μg/cm3, and for the BC45 strain it amounted over 80 μg/cm3. Obtained results prove that P. agglomerans may be used in the biological protection against phytopatogenic strains of R. solani.
Georgi Chernev, Nelly Christova, Lyudmila Kabaivanova and Lilyana Nacheva
In this study sol-gel hybrid materials in the system SiO2-chitosan (CS) - polyethylene glycol (PEG), as novel structures with potential application in bioremediation were investigated. The organic components - CS and PEG were used as structural modifiers for functionality improvement. The catabolic activity to n-hexadecane of Pseudomonas aeruginosa BN10 free and immobilized cells was estimated. The cell immobilization technique was employed to evaluate its efficiency on biodegradation and protective effect from high levels of hydrocarbons. The characteristics of obtained hybrid materials were investigated via X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Atomic-force microscopy (AFM) analyses. The obtained results revealed that the organic part in the synthesized hybrids is important for microstructure and defined properties creation. The rate of n-hexadecane mineralization by the bacterial strain was influenced by variation in cell densities applied in the immobilization procedures. Semi-continuous processes with multiple xenobiotic supplies were carried out. The synthesized by the sol-gel method hybrid matrices proved to be suitable carriers for realizing an effective biodegradation process of n-hexadecane by Pseudomonas aeruginosa BN10. Biodegradation of 50 kg/m3 of n-hexadecane was realized by free cells. Significantly greater quantity (150 kg/m3) was mineralized for 15 active cycles by entrapped bacterial cells. Biodegradation process with gradual increase of xenobiotic concentration reaching 30 kg/m3 for 120 h was also accomplished.
Sara Chikhi, Bachir Bouzid and Adhy’a Eddine Hamitouche
The development of a new clean, easy to handle process with similar efficiency to that of the conventional process is one of the most important challenges in green chemistry investigation. In this study, a new hybrid process was investigated; coupling coagulation-flocculation with adsorption using abundant and natural bioproducts (Chitosan and Ammi visnaga). The Chitosan/Ammi visnaga (coagulation/adsorption) system was studied for its Brilliant Green dye removal capacity. This new technique seems to be a good alternative method for wastewater treatment, showing satisfactory results with high rates of elimination that range around 90 %.