Diversity of protease-producing marine bacteria from sub-Antarctic environments

HECTOR A. CRISTOBAL; MARIA A.LOPEZ; ERIKA KOTHE; CARLOS M. ABATE

JOURNAL OF BASIC MICROBIOLOGY

WILEY-V C H VERLAG GMBH

Lugar: Jena; Año: 2011 vol. 51 p. 560 - 600

0233-111X

Two hundred and thirty marine bacteria were isolated from seawater and intestines of benthonic organisms collected from Beagle Channel, Argentina. Cultivable bacteria were characterized and classified as psychrotolerant, whereas few isolates were psychrophiles. These isolates were capable of producing proteases at 4 and 15 °C under neutral (pH 7.0), alkaline (pH 10.0) and acid (pH 4.5) conditions on different media which revealed 62, 33 and 22% producers at cold and 84, 47 and 33% producers at low temperatures, respectively. More protease producing strains (67%) were detected when isolated from benthic invertebrates as compared to seawater (33%) with protease production under neutral conditions showing milk protein hydrolysis halos between 27 and 30 ± 2 mm of diameter. Twenty-nine isolates exhibiting extracellular protease activity were detected using sterile membrane filter of 0.22 ìm. These were grouped into six operational taxonomic units by restriction analysis and identified based on 16S rDNA to be g-proteobacteria of the genera Pseudoalteromonas, Pseudomonas, Shewanella, Alteromonas, Aeromonas and Serratia. Plasmids were found to be harbored be eight strains, mainly within the isolates from benthonic organisms.