ALVARENGA adriana elizabet
capítulos de libros
Isolation and Molecular Characterization of Marine Bacteria Isolated from the Beagle Channel, Argentina
CRISTÓBAL, H.A.; ALVARENGA A.E.; ABATE C.M
The Marine Environment: Ecology, Management and Conservation.
Nova Science Publishers
Año: 2011; p. 87 - 118
Approximately 71% of the earth's surface is covered by oceans, and represent an enormous pool of potential microbial biodiversity and exploitable biotechnology or "blue biotechnology". This unexploited region resulted in an increasing interest to study marine microorganisms, the role of them in marine food webs, and biogeochemical cycling. In addition, to emphasize the study of marine bacteria capable of produced different novel enzymes and metabolites, represent a potential to biotechnological applications. Diverse marine microorganisms are classified into extremophiles groups, which play a main role in the biodegradation of organic matter in different marine ecosystems. One of these groups, the cold-adapted microorganisms, is interesting for processes that need cold-active enzymes at low temperatures, for example food processing and cold-wash laundry detergents. In the last decade, the focus of microbial diversity has changed due to 16S rDNA, housekeeping genes and metagenomic studies. As a result, the characterization of new sequences allowed the discovery of new genera of cultivated and uncultivated microorganisms, from samples of the marine ecosystem. These new species belong to the γ-and α-Proteobacteria divisions. Within the areas of exploration to understand the diversity of marine bacteria are sub-Antarctic waters of the Beagle Channel, Tierra del Fuego, Argentina. The Beagle Channel (55°07'18" S 66°25'00" W) is located at the southern end of America and is the international border between Argentina and Chile. Coastal areas are interesting to study because they are easily accessible and the water temperature ranges between 4.5 and 10°C, optimum for cold-adapted microorganisms. Marine bacteria were isolated from benthonic organisms intestines, and seawater samples. The samples were taken from different coastal areas of the Beagle Channel; they were enriched in modified LB medium with seawater and cultivated at 4 and 15ºC. Of 296 marine bacteria isolated, 55 were characterized by ARDRA analysis, 16S rDNA sequencing, and construction of phylogenetics trees. The gene sequences allowed us to determine their association with the class Proteobacteria, members of the following genera: Shewanella, Pseudomonas, Pseudoalteromonas, Serratia, Halomonas, Alteromonas, Psychrobacter. These microorganisms showed different glycosyl hydrolases activities, within this group are cellulase, endoglucanase, exoglucanasa, xylanase, β-glucosidase, α-rhamnosidase. In this chapter, we focus on the studies of marine bacteria, genes, enzymes and metabolites for biotechnological applications, as well as new cold-active enzymes applied to products whose manufacturing processes are performed at low temperatures.