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Applied and Environmental Microbiology, December 2000, p. 5148-5154, Vol. 66, No. 12
Department of Microbiology and Immunology and Pulp
and Paper Centre, University of British Columbia, Vancouver,
British Columbia V6T 1Z3 Canada
Received 28 March 2000/Accepted 14 September 2000
Resin acids are tricyclic terpenoids occurring naturally in trees.
We investigated the occurrence of resin acid-degrading bacteria on the Arctic tundra near the northern coast of Ellesmere Island (82°N, 62°W). According to most-probable-number assays, resin acid degraders were abundant (103 to 104
propagules/g of soil) in hydrocarbon-contaminated soils, but they were
undetectable (<3 propagules/g of soil) in pristine soils from the
nearby tundra. Plate counts indicated that the contaminated and the
pristine soils had similar populations of heterotrophs (106
to 107 propagules/g of soil). Eleven resin acid-degrading
bacteria belonging to four phylogenetically distinct groups were
enriched and isolated from the contaminated soils, and representative
isolates of each group were further characterized. Strains DhA-91,
IpA-92, and IpA-93 are members of the genus
Pseudomonas. Strain DhA-95 is a member of the genus
Sphingomonas. All four strains are psychrotolerant, with
growth temperature ranges of 4°C to 30°C (DhA-91 and DhA-95) or
4°C to 22°C (IpA-92 and IpA-93) and with optimum temperatures of 15 to 22°C. Strains DhA-91 and DhA-95 grew on the abietanes, dehydroabietic and abietic acids, but not on the pimaranes, isopimaric and pimaric acids. Strains IpA-92 and IpA-93 grew on the pimaranes but
not the abietanes. All four strains grew on either aliphatic or
aromatic hydrocarbons, which is unusual for described resin acid
degraders. Eleven mesophilic resin acid degraders did not use
hydrocarbons, with the exception of two Mycobacterium sp. strains that used aliphatic hydrocarbons. We conclude that
hydrocarbon contamination in Arctic tundra soil indirectly selected
for resin acid degraders, selecting for hydrocarbon degraders that
coincidentally use resin acids. Psychrotolerant resin acid degraders
are likely important in the global carbon cycle and may have
applications in biotreatment of pulp and paper mill effluents.
0099-2240/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Apparent Contradiction: Psychrotolerant Bacteria
from Hydrocarbon-Contaminated Arctic Tundra Soils That Degrade
Diterpenoids Synthesized by Trees
*
Corresponding author. Mailing address: Department of
Microbiology and Immunology, University of British Columbia,
#300-6174 University Blvd., Vancouver, British Columbia V6T 1Z3,
Canada. Phone: (604) 822-4285. Fax: (604) 822-6041. E-mail:
wmohn{at}interchange.ubc.ca.
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