Screening of Xylanase and Glucose Isomerase Producing Bacteria Isolated from Hot Springs in Turkey

Abstract

The aim of this study was screening of xylanase and glucose isomerase producing thermophilic bacteria isolated from some hot springs located to Aegean Region of Turkey. Total sixty eight thermophilic isolates (Anoxybacillus, Brevibacillus, Geobacillus, Aneurinibacillus, Thermus, Paenibacillus and Proteobacter) were collected previously from these fields and identified based on 16S rDNA gene sequences. The isolates were screened with plate assay for determining the xylanase and glucose isomerase production abilities seperately in order to find new strains for industrial processes. After an incubation period of two days for xylanase and 5-6 days for glucose isomerase at 50-60 °C, positive strains were determined. Enzyme producing strains were confirmed by spectrophotemetric measurements with crude enzyme extracts, birchwood xylan and glucose were used as substrates. Most of the strains (59 strains) were positive for xylan degradation while only sixteen of the strains had showed glucose isomerase activity. Fourteen of the strains have showed both xylanase and glucose isomerase activity. None of the Paenibacillus, Aneurinibacillus, and Proteobacter strains were glucose isomerase positive, although the glucose isomerase activity of Geobacillus strains were notably high. Both xylanase and glucose isomerase activities have observed at 50-60 °C which is suitable for biotechnological applications.