AbstractThe role of actinomycetes in the biodeterioration of wood was reviewed and found to be unclear. Twenty Streptomyces isolates previously isolated from decayed wood were characterised according to the criteria of the International Streptomyces Project. Discrepancies between keys developed for identification of Streptomyces were demonstrated and consequently it was found difficult to conclusively identify isolates to species level.
Monocultures of Streptomyces spp., Nocardia spp., Streptosporangium spp., Micromonospora spp., and Microbispora spp. were used to evaluate decay potential of actinomycetes in Pinus sylvestris L and Tilia vulgaris Hayne. Decay was assessed by weight loss and by micromorphological studies using light and scanning electron microscopy. Extensive weight loss studies and cellulolytic determinations were undertaken only on 20 Streptomyces isolates and although enzymatic studies showed that all were cellulolytic when extended tests were undertaken, only slight weight losses were produced in wood. One isolate, S . xanthochromogenus, produced significant weight losses in lime and consistently produced soft rot cavities in this timber.
An isolation technique using comminution, homogenisation, and a high temperature pretreatment was developed to quantify actinomycete presence in wood and it was found that 108 actinomycete propagules per gram of wood were consistently present in the latter stages of its decay in soil (95% of these were streptomycetes). These numbers indicated a significant actinomycete presence in wood at least in spore form and actinomycete biomass in wood may be greater than is indicated by these figures.
Streptomycete interactions with wood decay fungi were studied in pure culture and it was shown that S. xanthochromogenus and S. bottropensis could inhibit or stimulate both decay and nitrogen translocation to both lime and pine. The streptomycetes were also shown to transfer nitrogen to wood.
The role of actinomycetes in microbial succession and the biodeterioration of wood is discussed.
|Date of Award||Dec 1981|