Volume 11
Issue 2
Biotechnology
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Available Online: http://www.ejpau.media.pl/volume11/issue2/abs-03.html
BIODEGRADATION OF FEATHER KERATIN BY BACILLUS CEREUS IN PURE CULTURE AND COMPOST
Anna Rodziewicz, Wojciech £aba
Department of Biotechnology and Food Microbiology,
Wroc³aw University of Environmental and Life Sciences, Poland
ABSTRACT
The cultures of Bacillus cereus B5esz strain in feather keratin-containing media showed, that proteinceaous substrate was gradually degraded and next used as a carbon and nitrogen source. This strain biosynthesised extracellular enzymes, such as: keratinases, proteases and others. As a result, increases in soluble protein and amino groups concentration were observed, together with the release of inorganic sulphur compounds and medium alkalinization. This coincided also with increasing concentrations of thiol compounds. An excess of cystine-derived sulphur was accumulated in inorganic sulphates (IV and VI) or thiosulphates. The investigated bacterial strain in twelve-day cultures decomposed 70 % of feather keratin. Inoculation of feather-containing compost with B. cereus, initially resulted in predominance of spore-forming and thermophilic bacteria. After six weeks of composting, yeast or filamentous fungi were eliminated. Bacterial inoculum slightly accelerated the mineralization of feathers and increased the fertilizer value of the compost. Electron microscopy visualization of feather keratin fibres after composting, showed enhanced degradation of the feather structures. The degradation of feather keratin structures was conspicuous both in the medium and compost. The feathers were covered with a complex microbial matrix.
Key words: Bacillus cereus, keratinolysis, feather keratin, composting.
Anna Rodziewicz
Department of Biotechnology and Food Microbiology,
Wroc³aw University of Environmental and Life Sciences, Poland
Norwida 25, 50-375 Wroc³aw, Poland
email: Anna.Rodziewicz@wnoz.up.wroc.pl
Wojciech £aba
Department of Biotechnology and Food Microbiology,
Wroc³aw University of Environmental and Life Sciences, Poland
Che³mońskiego 37/41
51-630 Wroc³aw
Poland
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