Characterisation of actinomycetes community from the heavy metals polluted soil

VITĚZOVA MONIKA: Characterisation of actinomycetes community from the heavy metals polluted soil. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 5, pp. 1471–1478 The isolation of actinomycetes was performed from soil samples infl uenced by car-traffi c. The acute toxicity of soil leaches was tested by the help of Microtox® bioassay testing system which uses freeze dried luminescent bacteria Photobacterium phosphoreum as the test organisms. The content of heavy metals in biomass of soil microorganisms and in whole soil samples was determinate. 115 strains of actinomycetes were isolated and their total numbers in soil samples were estimated. The acute toxicity of soil infl uenced the total numbers of actinomycetes. By the help of DNA-DNA reassociation procedure the generic diversity of bacteria was estimated. The identifi cation and diff erentiation of streptomycetes from the total isolated actinomycetes was made using specifi c morphological criteria and the gas chromatography-fatty acid methyl ester (GC-FAME) analysis. FAME method is adequate only for diff erentiation of members of genus Streptomyces from other actinomycetes because of their characteristical profi le of fatty acids. soil microorganisms, actinomycetes, streptomycetes, heavy metals, FAME method, API ZYM It is well known fact that the traffi c is taking part in pollution of roads surrounding environment. The car-traffi c is an important source of fl uid and solid emissions, they are getting loose into the air especially in combustion processes (Hlavňa et al., 2000). Automobile exhaust gases are source of carbon dioxide, carbon monooxide, nitrogen oxides, ammonia, partially oxidized hydrocarbons, aldehydes, lead compounds and other heavy metals. The air-polluting substances enter into the soil and aff ect the soil microfl ora. The contamination by heavy metals causes a serious problem because they cannot be naturally degraded like organic pollutants and they accumulate in diff erent parts of the food chain. Several parameters of microbial activity could be used as good indicators of increasing concentration of heavy metals in soil (Smejkalova et al., 2003). Soil is a natural environment for actinomycetes (Zhang et al., 2013). Streptomycetes, one group of order Actinomycetales, represent one of the biggest societies in soil microfl ora. Streptomycetes are well adapted to this environment because of their high enzymatic activity (Hoskisson et al., 2012). Streptomycetes embodies the high enzymatic activity in soil decontamination proceses, they produce many hydrolytic enzymes which allow them to obtain important nutrients from hardly utilizable substrates. Streptomycetes are common inhabitants of the soil environment and are regarded as the most numerous actinomycetes isolated from soil (Williams et al., 1984). Streptomycetes in close cooperation with other soil organisms degrade biopolymers from vegetable and animal residuals. Predominantly found as spores, streptomycetes can germinate and grow in contaminated soils into a mycelial state form brief periods of time when nutrients become available (Mayfi eld et al., 1972). The aim of our study was to determine the infl uence of car-traffi c on the structure of soil microbial communities. 1472 Monika Vitězova MATERIAL AND METHODS