Ecological Engineering and Environment Protection

Abstract: Among four white-rot basidiomycetes tested, monocultures of Irpex lacteus and Pycnoporus coccineus accumulated the highest endoglucanase (53.2 and 61.5 U ml^-1), FPA (3.9 and 5.1 U ml^-1), and xylanase (58.9 and 58.6 U ml^-1) activities in submerged fermentation of crystalline cellulose. Co-cultivation of these two fungi accompanied with their synergism in enzyme production and provided the highest yields of cellulase and xylanase. By contrast, mixed cultivation of Trametes versicolor with P. coccineus 310 appeared to be unfavourable for cellulases and xylanase production. In co-cultivation of I. lacteus and P. coccineus it was established that the hydrolases yield depends on the growth substrates, nitrogen source, and their concentrations. The medium containing 2% avicel and 4% mandarin peels along with peptone at concentration of 40 mM provided an abundant growth of fungi and accumulation of 127 U ml^-1 CMCase, 6.6 U ml^-1 FPA, and 136.2 U ml^-1 xylanase activity.

Key words: basidiomycetes, co-cultivation, cellulase, xylanase, submerged fermentation, production optimization

THERMODYNAMIC PROGNOSIS OF MICROBIAL INTERACTION WITH IRON COMPOUNDS

Vira Govorukha, Olga Radchenko, Oleksandr Tashyrev

Abstract. Microbial redox-transformation of iron compounds is closely related to the environmental conditions defined by a set of physical and chemical factors, including the pH and Eh value. Thermodynamic calculations of all theoretically feasible ways of microbial interaction with iron compounds (mobilization/immobilization, oxidation/reduction) are presented. It was theoretically grounded that microorganisms were capable to perform a high activity in the biogeochemical cycles of carbon and iron. Obtained results can be used to prognose the transformation of iron compounds by microorganisms in natural and man-made ecosystems and create biotechnologies of microbial purification of water sources and wastewater from iron compounds.

Key words: microorganisms interaction with iron, thermodynamic prognosis, iron reduction, biogeochemical role of microorganisms, microbial biotechnologies.

REMOVAL OF COPPER (II) FROM AQUEOUS SOLUTION BY BIOSORPTION ONTO POWDER OF JERUSALEM ARTICHOKE

Tsvetko Prokopov

Abstract. Stalks’ powder of Jerusalem artichoke (Helianthus tuberosus L.) was tested as an agricultural waste product for the removal of Cu (II) ions from aqueous solution. Batch experiments were carried out to evaluate the effects of pH, biosorbent dosage, initial metal concentration and contact time. The maximum removal efficiency of about 71 % was reached at pH 4.0 by using of 5 g/dm³ biosorbent for 120, 90 and 60 min contact time, at 10, 50 and 100 mg/dm³ initial Cu (II) concentration, respectively. Pseudo-first-order, pseudo-second-order, Elovich’s equation and intraparticle diffusion models were applied to describe the obtained kinetic data. The pseudo-second-order model provided the best fit for experimental data with coefficient of determination grater than 0.99. Freundlich and Langmuir isotherm models were used to describe metal adsorption. Equilibrium data agreed well with Freundlich isotherm with R² = 0.968.

Keywords: biosorbent, heavy metals, copper ions, kinetics, isotherms.

AN EFFICIENT REGENERATION SYSTEM AND ANTIMICROBIAL ACTIVITY OF RUTA GRAVEOLENS L. PLANTS

N. Matvieieva, K. Drobot, L. Pasichnyk, N. Zhytkevych

Abstract. An efficient protocol of Ruta graveolens L. shoot regeneration has been developed. MS media supplemented with 3% sucrose, Kinetin, 6-Benzylaminopurine (BA) and α-Naphthylacetic acid (NAA) growth regulators were used to find out the regeneration ability of intermodal, root, petiole and leaf explants. Addition of BA in concentration 0.5 mg L^-1 promoted regeneration from petioles, roots and internodes with 100% frequency. The high frequency of shoot regeneration was also observed when the explants were cultivated on the MS basal medium with BA (0.5-1.0 mg L^-1) and NAA (0.05-0.5 mg L^-1). Extracts of R. graveolens regenerated plants exhibited antibacterial activity against Bacillus subtilis ATCC 6633, Staphylococcus aureus B918, A. rhizogenes A4 bacteria to the same extent as the extracts of initial plants. The extracts were not active against Escherichia coli and phytopathogenic bacteria. The method developed is simple and effective. It can be used for multiplication of plant material for the purpose of biologically active substances production and promote native ecosystems protection.

Keywords: Ruta graveolens L, shoot regeneration, growth regulators, antimicrobial activity.

INVESTIGATION OF FOREST VEGETATION DYNAMICS BEFORE AND AFTER A FIRE BY USING AEROSPACE DATA

Nataliya Stankova, Roumen Nedkov

Abstract: The aim of this study is to investigate the forest vegetation dynamics before and after a fire that took place in the summer of 2007 on the territory of Haskovo region, Bulgaria. To achieve this goal, NDVI and VCI indices have been generated once every year during the vegetation period by means of Terra MODIS imagery. The variations of NDVI and VCI indices have been examined before and after the fire by means of satellite images. The differences in NDVI and VCI variations have been analyzed for the period 2005–2014. The correlation between the two indices has been assessed on the basis of the obtained results. The evaluation of the obtained results has been validated by means of aerial images of the territory of the fire.

Keywords: forest fire, post-fire recovery, remote sensing, NDVI, VCI, MODIS.

ASSESSMENT OF VEGETATION COVER DEGRADATION AND SOIL EROSION IN CHUPRENE RESERVE (NORTHWESTERN BULGARIA) USING REMOTE SENSING AND GEOGRAPHICAL INFORMATION SYSTEMS

Daniela Avetisyan

Abstract. Vegetation cover degradation and soil erosion lead to processes connected with alternation of landscape structure and statement of landscape components. Simultaneously, these processes are accompanied by changing of heat – moisture ratio in landscapes and continuously running drought processes. Variations in solar activity can be considered as one of the possible factors causing vegetation cover degradation, drought, and desertification. In the recent study, vegetation cover degradation is assessed using satellite images and the vegetation indices Normalized Difference Vegetation Index (NDVI), Vegetation Condition Index (VCI), and Normalized Multi-band Drought Index (NMDI). Vegetation condition is one of the main factors of Universal Soil Loss Equation (USLE) used as basis of soil erosion assessment. Parallel study of both processes in 2000, 2007, and 2014 allows tracing of their dynamics and deriving possible trend in their progress.

Key words: Vegetation degradation, soil erosion, vegetation indices, USLE factors, northwestern Bulgaria

RESISTANCE OF YEAST AND ACTINOMYCETE POPULATIONS AT CULTIVATION IN A MEDIUM WITH INSECTICIDES

Dencho Denchev, Lyudmila Kabaivanova

Abstract: Soil microflora, as a component of biogeocenoses is experiencing different impacts by pesticides. Acting on the individual microbial species they affect and modify the ecosystems as a whole. On the other hand, many microorganisms can perform transformation and mineralization of pesticides. The aim of the study is to establish the nature of the interaction and sustainability of the model yeast and actinomycete populations with insecticide λ-cyhalothrin in laboratory conditions, as well as their ability to mineralize it. It has been found that a concentration of 0, 02% insecticide enhances the efficiency of utilization of the carbon substrate by the yeast population and inhibited actinomycetes at all concentrations tested. The addition of an insecticide in the medium decreases the activity of amylolytic enzymes and increases that of superoxide dismutase. The yeast strain Hansenulla anomala var.Schneggii can use λ-cyhalothrin as a sole carbon source.

Keywords: pesticides, λ- cyhalothrin, yeast, actinomycetes, growth, enzyme activity

BALANCE OF SOLAR AND WIND ENERGY SOURCES

Ludmil Stoyanov, Gilles Notton, Vladimir Lazarov

Abstract: In a hybrid system, the solar and wind power productions are used together increasing the system reliability. This work shows how solar energy and wind energy can be complementary (or not) using hourly values of wind speed and solar irradiation collected in 13 sites located in Bulgaria and Corsica. The renewable potential of these sites is estimated and their complementarity nature is studied at various time scales. The results show that wind and solar energy do not support always each other and depends largely on the season, on the site and on the time scale.

Keywords: hybrid systems; solar energy; wind energy; renewable energy sources

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