Previous studies of fungal decay have mainly examined long term
effects of wood decay. In contrast, the present work, was
designed to quantify fungal degradation of wood during incipient
decay. Three facultatively anaerobic, dimorphic fungi were
isolated from the rumen of sheep. These fungi were identified as
Mucor racemosus, Candida tropicalis and Geotrichum capitatum.
Scanning electron microscopy showed that these fungi colonised
Pinus patula and Eucalyptus grandis extensively but did not
appear to degrade the wood. The obligate anaerobe Neocallimastix
frontalis colonised wood very sparsely, whereas the white rot
bas id iomycetes Cori 01 us versicolor, and Phanaerochaete
chrysosporium, and the brown rotters Coniophora puteana and
Lentinus lepideus, colonised wood under both aerobic and
anaerobic conditions. The extents of colonisation were greater
under aerobic conditions. The work then quantified the effects
of the basidiomycetes C. versicolor, P. chrysosporium, C. puteana
and L .lepideus, and the non-decay mould, M. racemosus in
individual and coculture experiments. Wood colonisation was
quantified by Kjeldahl nitrogen determinations converted to
biomass assays, and degradation was quantified by weight losses,
and Klason lignin determinations. Furthermore, the degraded wood
samples were also analysed by HPLC analysis of hydrolysates and
their sugar contents were determined to establish whether the
glucose of cellulose and xylose + mannose of hemicellulose had
been utilised by the respective fungi. The extent and nature of
sugar utilisation by monocultures and cocultures in wood were
then compared with the biomass and degradation data. statistical
analyses of' these comparisons correlated the extents of
colonisation, degradation, and the patterns of wood sugars
predominantly utilised by each fungus. The results of the
corresponding glucose, xylose and 'lignin analyses confirmed the
brown rot physiological capacity of C.puteana in both'woods. The
white rot fungi behaved as simultaneous rotters and,<M·~<.racemosus
was shown to be ligninolytic in P .patula. The white rot
physiological capacity of C.versicolor was confirmed in 'E.grandis
and that of P.chrysosporium in P.patula. Antagonism and
synergism in wood was detected between individuals 'within cocultures
during incipient decay. The significance of these
findings becomes apparent when decayed wood of unknown history is
analysed as described here. Such findings may be interpreted to
provide valuable information describing the physiological nature
of the responsible fungi, even if these are no longer viable or
culturable. / Thesis (M.Sc.)-University of Durban-Westville, 1992
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/8095 |
| Date | January 1992 |
| Creators | Singh, Vahunth. |
| Contributors | Baecker, Albin A. W. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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