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MEPS 229:11-18 (2002)
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Abstract
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Resistance of the marine diatom Thalassiosira sp. to toxicity of phenolic compounds
Charles R. Lovell1,*, Niels T. Eriksen2,**, Alan J. Lewitus2,3, Yung Pin Chen1
1Department of Biological Sciences and
2Belle W. Baruch Institute of Marine Biology and Coastal Research, University of South Carolina, Columbia, South Carolina 29208, USA
3Marine Resources Research Institute, South Carolina Department of Natural Resources, Charleston, South Carolina 29412, USA
*E-mail: lovell@biol.sc.edu **Present address: Department of Life Sciences, Aalborg University, Sohngaardsholmsvej 49, 9000 Aalborg, Denmark
ABSTRACT: In many nearshore marine systems, microalgae can be chronically exposed to anthropogenic and biogenic phenolic and halophenolic compounds that accumulate in surficial sediments. Although biodegradation of some phenolic compounds has been
demonstrated in freshwater algae, this capability has not been tested in marine species. We examined a ubiquitous marine diatom, Thalassiosira sp. HP9101, for its capacity to tolerate, and/or utilize phenol and benzoic acid. We also examined the
aromatic ring cleavage reactions of this diatom and its capacity to dechlorinate chlorophenolic compounds. Axenic Thalassiosira sp. cultures were grown at 60 µE m-2 s-1 (12: 12 h light: dark cycle) in the presence or absence
of phenol, benzoate, catechol or protocatechuate and their growth kinetics and physiological responses determined. Thalassiosira sp. was inhibited by catechol and protocatechuate. Growth in the presence of 1 mM phenol was observed only after an
extended lag and was quite slow. Growth in the presence of 0.25 mM phenol occurred after a much shorter lag and phenol was taken up by these cultures at an estimated rate of 0.08 fmol phenol cell-1 h-1. No inhibition of
Thalassiosira sp. by 1 mM benzoate was observed. Growth stimulation by added phenolic substrates was not demonstrated, although phenol-supplemented Thalassiosira sp. produced substantial levels of protocatechuate 3,4-dioxygenase and
protocatechuate 4,5-dioxygenase, the ortho- and meta-pathway aromatic ring cleavage enzymes, respectively. Only protocatechuate 4,5-dioxygenase activity was detected in Thalassiosira sp. grown with 1 mM benzoate. Phenol supplemented
Thalassiosira sp. was also capable of dechlorinating monochlorophenols, 3,5-dichlorophenol, and 2,4,6-trichlorophenol. These reactions were NADH-dependent and were not observed in control cultures grown without phenol.
KEY WORDS: Benthic microalgae · Marine diatom · Phenol · Aromatic ring cleavage · Haloaromatics · Dehalogenation
Full text in pdf format
Published in MEPS Vol.
229
(2002) on March 20
Print ISSN: 0171-8630; Online ISSN: 1616-1599.
Copyright © Inter-Research, Oldendorf/Luhe, 2002
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