Hydrocarbon biodegradation by psychrotrophic bacteria Project 42 2002-2004

English

Project 42 2002-2004
The aim of this project is to continue with the study of
psychrotrophic bacteria able to degrade hydrocarbons and to evaluate
their potential application in bioremediation processes. For this
purpose we will complete the recently initiated assays using
contaminated Antarctic soils in microcosms systems, analysing the
abiotic elimination, activity of the indigenous microflora and the
effect of bioaugmentation with hydrocarbon-degrading strains
previously isolated and characterised (Acinetobacter B-2-2,
Rhodococcus ADH, etc.). The effect of other environmental factors as
pH value and nutrients (N and P) concentration on the biodegradation
will be evaluated. Owing to the low activity showed by the previously
isolated strains on PAHs, we will make new screenings programs in
order to isolate and characterise (using biochemical and molecular
techniques) new Antarctic bacterial isolates able to utilise PAHs as
sole carbon and energy source. Degrading activity of the strains will
be tested in microcosms systems under natural climate conditions in
Antarctica. The use of bacterial consortia as inoculum as well as the
evaluation of changes occurring in natural soil bacterial communities
during the bioremediation processes makes necessary to have adequate
taxonomic tools. This work will be carried out by using biochemical
and physiological methods and, in a second step by molecular
techniques. These techniques include amplification of the 16S rARN
gene and further analysis by denaturing gradient gel electrophoresis
(DGGE) and restriction fragments length polymorphism (RFLP). In
addition, we will continue evaluating the hydrocarbons pollution
degree in Jubany and Marambio stations comparing the results to such
obtained from the microcosms systems. We hope to develop in the
middle/long term microbiological processes useful for the "in situ"
treatment of polluted Antarctic soils. These processes will avoid the
high costs that the movements of the contaminated soils to the
continental areas imply. The bioremediation techniques emerging from
this study will be useful in many other cold areas where the low
temperatures represent the limiting factor of the bioremediation
process.

Spanish

Resumen del Proyecto: Este proyecto tiene por objetivo continuar con
el estudio de las bacterias antarticas productoras de exoenzimas de
interes industrial que posean alta actividad a baja
temperatura. Adicionalmente, dado la importancia ecologica que poseen
estas actividades bacterianas, se planea realizar el estudio profundo
de las comunidades bacterianas en donde las cepas seleccionadas se han
aislado. Se realizaran screenings de bacterias sicrofilas utilizando
medios selectivos (en placas o en medios liquidos) que permitan
visualizar las actividades enzimaticas de interes (proteasas,
xilanasas, amilasas, lipasas, etc.). Las cepas de interes se
estudiaran a fin de determinar su caracter sicrofilo y su capacidad de
produccion de enzimas bajo diferentes condiciones de cultivo a fin de
optimizar la produccion. Eventualmente, se realizara la purificacion y
caracterizacion de las enzimas con mayor potencial biotecnologico. Se
tipificaran las cepas de interes por secuenciacion del gen del ARNr
16S y se analizaran las comunidades naturales de donde provienen por
electroforesis en geles desnaturalizantes (DGGE). Dado el interes que
la informacion genetica de estos microorganismos extremofilos ha
despertado en importantes industrias biotecnologicas, en colaboracion
con ellas (ya se estan analizando los borradores de los proyectos) se
realizaran estudios de secuenciacion de grandes porciones del genoma
de algunos de estos microorganismos con el objeto de encontrar
secuencias homologas a genes codificantes de proteinas de aplicacion
industrial.
Duracion: 2002-2004