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Effects of the humic substances of de-inking paper sludge on the antagonism between two compost bacteria and Pythium ultimum
- Source :
- FEMS microbiology ecology. 52(2)
- Publication Year :
- 2004
-
Abstract
- We investigated the in vitro influence of humic substances (HS) extracted from de-inking paper sludge compost on the inhibition of Pythium ultimum by two compost bacteria, Rhizobium radiobacter (Agrobacterium radiobacter) and Pseudomonas aeruginosa. When low concentrations (5 or 50 mg l � 1 ) of HS were added to the culture medium, fungal inhibition by R. radiobacter significantly increased (P < 0.01) by 2–3%. In contrast, these low levels of HS had no effect on P. ultimum inhibition by P. aeruginosa. The Fe, chelated by HS, was in part responsible for the decrease of P. ultimum inhibition by the bacteria when increasing amounts of HS were added in the culture medium. The addition of 500 mg l � 1 of humic acids isolated from de-inking paper sludge compost or from fossil origin completely eliminated the inhibition of P. ultimum by R. radiobacter. This Fe effect also stimulated growth of R. radiobacter and reduced its siderophore production in a minimal medium supplemented with HS as sole source of Fe. The results showed that HS influence microbial antagonism when added to a culture medium. However, this effect varies with different factors such as the type of bacteria, concentration of HS, molecular weight and Fe content. 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.
- Subjects :
- Paper
Siderophore
Ecology
biology
Bacteria
Sewage
Compost
Fossils
Pythium
engineering.material
biology.organism_classification
Applied Microbiology and Biotechnology
Microbiology
Pythium ultimum
engineering
Food science
Medical Waste Disposal
Antagonism
Humic Substances
Soil Microbiology
Agrobacterium radiobacter
Pseudomonadaceae
Subjects
Details
- ISSN :
- 01686496
- Volume :
- 52
- Issue :
- 2
- Database :
- OpenAIRE
- Journal :
- FEMS microbiology ecology
- Accession number :
- edsair.doi.dedup.....9ba1c752d775d60bfa73a0c53ec588d9