Newly isolated Bacillus clausii GMBAE 42: an alkaline protease producer capable to grow under higly alkaline conditions.

AIMS: The isolation and identification of new Bacillus sp. capable of growing under highly alkaline conditions as alkaline protease producers. METHODS AND RESULTS: A Bacillus strain capable of growing under highly alkaline conditions was isolated from compost. The strain is a Gram-positive, spore-forming, motile, aerobic, catalase- and oxidase-positive, alkaliphilic bacterium and designated as GMBAE 42. Good growth of the strain was observed at pH 10. The strain was identified as Bacillus clausii according to the physiological properties, cellular fatty acid composition, G + C content of genomic DNA and 16S rRNA gene sequence analyses. The result of 16S rRNA sequence analyses placed this bacterium in a cluster with B. clausii. The G + C content of the genomic DNA of the isolate GMBAE 42 was found to be 49 mol%. The crude extracellular alkaline protease produced by the isolate showed maximal activity at pH 11.0 and 60 degrees C. CONCLUSIONS: The results suggest that isolated strain GMBAE 42 is a new type of B. clausii capable of growing at pH 10.0 and produce extracellular alkaline protease very active at pH 11.0. SIGNIFICANCE AND IMPACT OF THE STUDY: Isolated strain could be used in commercial alkaline protease production and its enzyme can be considered as a candidate as an additive for commercial detergents.

The effect of ethylenediamine-tetraacetic acid on Candida albicans.

OBJECTIVES: The aim of this study was to evaluate the antifungal effect of ethylenediamine-tetraacetic acid (EDTA) on Candida albicans, comparing it with that of various disinfectants and common antifungal agents. STUDY DESIGN: Two clinical oral isolates and 1 standard strain of C albicans were included in this study. Main contents of the test solutions were sodium hypochlorite, EDTA, chlorhexidine, hexetidine, benzalkonium chloride, povidone-iodine, nystatin, and ketoconazole. The agar diffusion method was used to determine the antifungal effects of the solutions. Zones of inhibition were recorded and the results were analyzed statistically by using a 2-way analysis of variance. RESULTS: EDTA demonstrated the highest antifungal activity in comparison with routine antifungal drugs and all other solutions (P <.0001). Oral cavity isolate was more resistant to the test solutions (P <.0001). CONCLUSION: The selection of irrigating and disinfecting solution in root canals of patients with a particularly high incidence of oral candidiasis gains extreme importance. EDTA may be strongly recommended during endodontic therapy of these patients.