Water-related environments: a multistep procedure to assess the diversity and enzymatic properties of cultivable bacteria.

Studying the culturable portion of environmental bacterial populations is valuable for understanding the ecology, for discovering taxonomically interesting isolates and for exploiting their enzymatic abilities. In this study, diverse water-related samples, iced water (3 °C) from river, the sediment (29 °C) and water (55 °C) of a hot-spring, were investigated by two cultivation strategies, Dry and novel Wet approach. The isolates were clustered by fluorescent internal transcribed spacer PCR and identified by 16S rRNA sequencing. Several bacterial groups were also sub-typed through the application of Random Amplified Microsatellite Polymorphisms method. A broad enzymatic screening of all bacterial isolates was performed in order to assess the proteolytic, cellulolytic, lipolytic, esterolytic, amylolytic properties, as well as catalase and peroxidase activities. The Wet cultivation demonstrated to be suitable for the isolation of potential new species belonging to genera Massilia, Algoriphagus, Rheinheimera and Pandoraea. Valuable microbial resources with extensive enzymatic activities were recognized among the psychrophilic (Pantoea brenneri and Serratia sp.), mesophilic (Pandoraea, Massilia, Pseudomonas, Stenotrophomonas, Bacillus and Aeromonas) and thermophilic bacteria (Aeribacullus pallidus and Geobacillus kaustophilus). The experimental strategy developed in this study includes simple investigation tools able to reveal the genetic and enzymatic peculiarities of isolated microorganisms. It can be applied to different kinds of aquatic samples and extreme environments similar to those described in this study.