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Your search keyword '"Steffen, Kari T."' showing total 20 results
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6. Degradation of benzo[a]pyrene by the litter-decomposing basidiomycete Stropharia coronilla: role of manganese peroxidase

Author

Steffen, Kari T., Hatakka, Annele, and Hofrichter, Martin

Subjects
Biodegradation -- Research, Benzopyrene -- Physiological aspects, Enzyme activation -- Physiological aspects, Manganese -- Influence, Manganese -- Physiological aspects, Biological sciences
Abstract

Research demonstrates that Stropharia coronilla metabolizes and mineralizes benzo[a]pyrene and manganese(II) ions significantly stimulate this process by four to twelve times, respectively. Data indicate that the stimulatory effects is mediated by the ligninolytic enzyme manganese peroxidase, whose activity increases upon manganese addition.

Published
2003

19. Modification of humic acids by the compost-dwelling deuteromycetePaecilomyces inflatus.

Author

Kluczek-Turpeinen, Beata, Steffen, Kari T., Tuomela, Marja, Hatakka, Annele, and Hofrichter, Martin

Subjects
HUMIC acid, PAECILOMYCES, COMPOSTING, FUNGI imperfecti, MICROBIAL physiology
Abstract

The soil moldPaecilomyces inflatusis capable of modifying and partially mineralizing synthetic and natural humic acids (HAs) in compost environments. HA degradation studies using a synthetic HA (14C-HA) in autoclaved compost microcosms showed that, after 12 weeks of cultivation,P. inflatusmineralized approximately 5% of the14C-labeled HA to14CO2, while 6% of the14C-HA was converted into14C-labeled water-soluble fragments (fulvic-acid-like fraction). About 40% was still present as NaOH-soluble HA representing unmodified or only slightly modified humic material (compared with 60% in the controls). Modification of natural HAs extracted from compost was followed by their partial decolorization (30%) in liquid cultures ofP. inflatus. Bleaching of the medium was accompanied by moderate changes in the molecular mass distribution of both the HA and fulvic-acid fractions, which were analyzed with high-performance size exclusion chromatography. HA modification was most pronounced during the primary growth phase of the fungus and was associated with increased laccase activity. [ABSTRACT FROM AUTHOR]

Published
2005
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