Novel Extremophiles
Staff
Seventy-five aerobic heterotrophs have been isolated from a packed-column bioreactor inoculated with soil from Antarctica. The column was maintained at 10 degrees C and continuously fed with a casein-containing medium to enrich protease producers. Twenty-eight isolates were selected for further characterization on the basis of morphology and production of clearing zones on skim milk plates. Phenotypic tests indicated that the strains were mainly psychrotrophs and presented a high morphological and metabolical diversity. The extracellular protease activities tested were optimal at neutral pH and between 30 and 45 degrees C. 16S ribosomal DNA sequence analyses showed that the bioreactor was colonized by a wide variety of taxons, belonging to various bacterial divisions: alpha-, beta-, and gamma-Proteobacteria; the Flexibacter-Cytophaga-Bacteroides group; and high G+C gram-positive bacteria and low G+C gram-positive bacteria. Some strains represent candidates for new species of the genera Chryseobacterium and Massilia. This diversity demonstrates that the bioreactor is an efficient enrichment tool compared to traditional isolation strategies.
CAMR culture collection
Isolation of novel extremophiles provides a platform for further work and, more specifically, isolation of novel enzymes. Novel extremphiles isolated by the CER expand the CAMR Culture Collection of Thermophilic Micro-organisms. The collection, recently acquired by the CER, comprises over 2,000 thermophilic organisms that have been isolated from environmental samples obtained from around the world by the staff of CAMR (Centre for Applied Microbiological Research, Porton Down) over the past 25 years.
The Packed-column bioreactor | Schematic representation.
