Isolation, characterization and molecular identification of protease producing bacteria from Tashkooh mountain located in Ahvaz, Iran

Abstract

Thermophilic microorganisms have gained worldwide importance due to their remarkable potential to produce thermostable and thermoactive enzymes that have wide applications in pharmaceuticals and industries. Therefore, the isolation of thermophilic bacteria from natural sources and their identification are very important in terms of discovering new industrial enzymes. The aim of this research was therefore the isolation of protease producing thermophilic bacteria from Tashkooh or firing mount located in Ahvaz, Iran. 8 bacterial isolates were screened. These strains were examined for the existence of extracellular protease activity. All 8 isolated bacteria showed proteolytic activity on nutrient agar with skim-milk. 3 bacteria showed their optimum growth at alkaline pH and grew maximally at different temperature in the thermophilic range and had proteolytic activity at pH 11 in 70?C and pH 9 in 55?C.The best carbon source for proteolytic activity was starch. After performing some phenotypic tests determined that all the isolates were Gram positive, endospore forming rods, aerobic, capable to produce catalase, amylase and gelatinase enzymes and they were identified as Bacillus sp. The best isolated bacteria was identified molecularly with the aid of 16S rRNA sequencing and data revealed that the Bacillus subtilis strain G-13 (GenBank accession No. KJ139434.1).The investigation confirmed that the isolate to be a true thermophile and could be a source of thermostable protease which can be exploited for pharmaceutical and industrials applications.DOI: http://dx.doi.org/10.3126/ijls.v9i2.12054 International Journal of Life Sciences 9 (2) : 2015; 39-42