| Abstract [eng] |
Plants, bacteria and fungi are known to synthesize pectic polysaccharides degrading enzymes called pectinases. These enzymes are important for plant growth and development, fruit ripening, phytopathogenesis etc. The aim of this study was to select biotechnologically important strains of endospore- forming bacteria with the highest pectinolytic activity as well as characterize pectinolytic enzymes from the crude protein extract. 8 out of 80 tested strains were selected for the experiments of growth curve measurement. PCR and 16S rRNA gene sequence analysis ascertained that two pectinolytic strains with the highest activity are closely related to Geobacillus thermodenitrificans NG80-2. Accordingly, these two strains were named Geobacillus sp. strain No. 3 and No. 4. Further analysis was performed with Geobacillus sp. strain Nr. 3 which was grown in the liquid medium with pectin. The crude protein extract was prepared using supernatant of the culture and then analysed spectrofotometrically for lyases and hydrolases activity, pectic substrates specificity, and thermostability. For further examinations electrophoretic and zymografic analyses were used. It was demonstrated that Geobacillus sp. strain No. 3 secretes at least two enzymes: pectin and polygalacturonic acid lyase and pectin hydrolase. For lyase, molecular mass (60-70 kDa), temperature optimum (60 °C) and pH optimum (7.0) were determined. |
