Screening of protease, cellulase, amylase and xylanase from the salt-tolerant and thermostable marine Bacillus subtilis strain SR60

Abstract

Background: The marine environment harbours different microorganisms that inhabit niches with adverse conditions, such as temperature variation, pressure and salinity. To survive these particular conditions, marine bacteria use unique metabolic and biochemical features, producing enzymes that may have industrial value. Methods: The aim of this study was to observe the production of multiple thermoenzymes and haloenzymes, including protease, cellulase, amylase and xylanase, from bacterial strains isolated from coral reefs Cabo Branco, Paraiba State, Brazil. Strain SR60 was identified by the phylogenetic analysis to be Bacillus subtilis through a 16S ribosomal RNA assay. To screening of multiples enzymes B. subtilis SR60 was inoculated in differential media to elicit the production of extracellular enzymes with the addition of a range of salt concentrations (0, 0.25, 0.50, 1.0, 1.25 and 1.5 M NaCl). Results: The screening showed a capacity of production of halotolerant protease, cellulase, amylase and xylanase and thermostable by the isolate (identified as B. subtilis SR60). Protease, cellulase, amylase and xylanase production were limited to 1.5, 1.5, 1.0 and 1.25 M NaCl, respectively. Conclusions: Bacillus subtilis SR60 was shown in this study be capable of producing protease, cellulase, amylase and xylanase when submitted to a high salinity environment. These data demonstrate the halophytic nature of SR60 and its ability to produce multiples enzymes.