Use of a packed-column bioreactor for isolation of diverse protease-producing bacteria from antarctic soil.
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.
Wery
Nathalie
N
Centre for Extremophile Research, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK. bssmjd@bath.ac.uk
Gerike
Ursula
U
Sharman
Ajay
A
Chaudhuri
Julian B
JB
Hough
David W
DW
Danson
Michael J
MJ
D000864:Antarctic Regions; D001419:Bacteria / Q000145:classification* / Q000201:enzymology / Q000254:growth & development / Q000302:isolation & purification*; D019149:Bioreactors; D003470:Culture Media; D004275:DNA, Ribosomal / Q000032:analysis; D010450:Endopeptidases / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology
D003470:Culture Media; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D010450:Endopeptidases