The impacts of long-term polycyclic aromatic hydrocarbons (PAHs) and heavy metal pollution on soil microbial communities functioning were studied in soils taken from an old coke plant. The concentrations of PAHs in the tested soils ranged from 171 to 2137 mg kg-1. From the group of tested heavy metals, concentrations of lead were found to be the highest, ranging from 57 to 3478 mg kg-1, while zinc concentrations varied from 247 to 704 mg kg-1 and nickel from 10 to 666 mg kg-1. High dehydrogenase, acid and alkaline phosphatase activities were observed in the most contaminated soil. This may indicate bacterial adaptation to long-term heavy metal and hydrocarbon contamination. However, the Community Level Physiological Profiles (CLPPs) analysis showed that the microbial functional diversity was reduced and influenced to a higher extent by some metals (Pb, Ni), moisture and conductivity than by PAHs.

Since fluoroquinolone (FQ) antibiotics are extensively used both in human and veterinary medicine their accumulation in the environment is causing increasing concern. The aim of the study was to isolate a microbial consortium resistant to ofl oxacin and norfl oxacin and able to biodegrade both antibiotics. Green compost was used as a source of microorganisms. The biodegradation effi ciency was monitored by changes of antibiotics concentrations and toxicity. The microbial consortium was composed of two bacterial isolates: Klebsiella pneumoniae (K2) and Achromobacter sp. (K3) and two fungi Candida manassasensis (K1) and Trichosporon asahii (K4). All the isolates were characterized as highly resistant to both antibiotics – ofl oxacin and norfl oxacin. FQs were supplied individually into the culture medium in the presence of an easily degradable carbon source – glucose. Biodegradation of norfl oxacin was much faster than ofl oxacin biodegradation. During 20 days of the experiment, the norfl oxacin level decreased by more than 80%. Ofl oxacin was generally biodegraded thereafter at relatively slow biodegradation rate. After 28 days the ofl oxacin level decreased by 60%. Similarly, the toxicity of biodegraded antibiotics decreased 4-fold and 3.5-fold for norfl oxacin and ofl oxacin, respectively. The ability of the bacterial-fungal consortium to degrade antibiotics and reduce toxicity could help to reduce environmental pollution with these pharmaceutical.

Previous studies indicated that particle size distribution affects the composition of keratinolytic and keratinophilic fungi in sewage sludge. The present study was to determine the composition of these fungi in sludge particle size fractions (> I, 1-0.5, 0.5--0.25, 0.25--0.125, 0.125-0.063, O 063--0.032 and < 0.032 mm) in a model experiment. I n the original sludge sample and its fractions, the composition of keratinolytic and kcratinophilic fungi was determined by using the hair baiting method. The composition of actidioneresistant fungi was also determined by using the dilution method and the Wiegand medium supplemented with chloramphenicol ( I 00 mg/dm') and actidione (500 mg/dm3). The number of keratinolytic and keratinophilic fungi isolated by the hair baiting method was lower in fractions than in the original sludge sample. In contrast, fungal quantities obtained by the dilution method were higher in fractions than in the original sludge sample. Qualitative differences were also observed. The conclusion was that nutrient factors associated with sludge particle size fractions, chietly total sulfur content and C:S ratio, affected the composition of keratinolytic and keratinophilic fungi in the sludge more than the fungal propagule quantities (inocula).

TCE artificially contaminated soil was cleaned under anaerobic, reductive conditions. A laboratory scale treatability studies were carried out to determine optimal physico-chcmical and microbiological parameters for biorcmcdiation process. Upon treatability studies results a sewage sludge mixture was chosen as a microorganism's source. The chlorinated solvents contaminated soil bioreactor (CSCS bioreactor) was designed and built. It consists of a 6 m3 reactor vessel, a gas recirculation system, a leachate recirculation system and a data acquisition system. The bioreactor vessel was designed as a continuous gas flow packed bed reactor. During 210 days 4 Mg of soil containing approximately 350 mg TCE/kg of soil has been completely remediated under anaerobic conditions. The obtained results indicate that the stepwise dechlorination of TCE to ETH occurs in the bioreactor. Increasing amounts of chloride in the leachate were correlated with dechlorination.

The present study is focused on the evaluation of bioeffects of silver nanoparticles (AgNPs) synthesized by Bacillus subtilis strain I’-1a, the producer of iturin A lipopeptide biosurfactant. The following properties of biologically synthesized silver nanoparticles (bio-AgNPs) were evaluated: in vitro cytotoxicity, antioxidant properties, and metabolic activities of mammalian cells. As a control, chemically synthesized silver nanoparticles (chem-AgNPs) were used. In vitro, antioxidant activity of bio-AgNPs showed a significant effect on the scavenging of free radicals. Bio-AgNPs can be potent natural antioxidants and can be essential for health preservation against oxidative stress-related degenerative diseases, such as cancer. The cell viability of human skin fibroblasts NHDF was remarkably inhibited in the presence of both AgNPs. However, bio-AgNPs were more active than chem-AgNPs. In our experiment, microarrays PM-M1–PM-M4 were used to evaluate the growth of NHDF fibroblast cells in the presence of bio-AgNPs and chem-AgNPs. The NHDF fibroblast cells were more active in the presence of bio-AgNPs than in chem-AgNPs. Probably, the presence of biosurfactant produced by Bacillus subtilis I’-1a significantly increased the stability of biogenic AgNPs and enhanced their biological activities and specific interaction with human DNA. Furthermore, the evaluated biological activities were enhanced for the biosurfactant-based AgNPs.