Prospecting soil bacteria from subtropical Brazil for hydrolases production

Abstract

Eighteen bacterial strains were isolated from soil of an urban area located in a transition zone between the Atlantic Forest and Pampa biomes, in southern Brazil. These strains were screened for cellulolytic, lipolytic and proteolytic potentials. Eleven isolates (61%) were able to produce cellulolytic enzymes on carboxymethylcellulose (CMC) agar plates, 14 isolates (78%) were proteolytic on skim milk agar plates, and all isolates demonstrated lipolytic/esterolytic potential on tributyrin agar (TBA) plates. From the 18 bacteria, nine (50%) were shown to produce the three investigated enzyme activities. Selected isolates were then evaluated for growth and enzyme production at different conditions of temperature and pH on CMC agar, TBA, and feather meal agar plates. As a general trend, growth and hydrolysis zones were observed at pH 6.0–9.0 and 30–37°C. Sequencing of 16S rRNA gene fragments indicated that 10 isolates belonged to the genus Bacillus, three to Lysinibacillus genus, and the remaining isolates were representatives of Serratia, Phyllobacterium, Paenibacillus, Acinetobacter, and Curtobacterium. The isolate Bacillus sp. CL18 displayed competence for feather degradation when cultured in mineral medium (30°C, pH 7.0) containing a single feather as the only organic substrate. Results from bioprospection indicate the functional versatility of the bacterial isolates, which might be of significance from both ecological and biotechnological perspectives.