FUNGAL SUCCESSION AND BIODEGRADTION OF RUBBER SAW DUST

Abstract

Sri Lanka has a long tradition of saw milling, But the waste product (saw dust) from thesemills is not adequately utili sed for beneficial purposes. In a functioning sawmill about twohundred kilograms of organic matter is dispelled as saw dust everyday.

Saw dust samples were kept in the garden exposed to normal climatic conditions, a greenhouse or on a laboratory bench for this study. Fungal species that appeared on sawdustwere isolated, identified and number of fungal colonies were counted by dilution platecount technique. During this study seven prominent fungal genera were observed. Fourspecies (Fusarium sp, Penicillium sp, Stemphy/ium sp, Trichodema sp) out of seven wereDeuteromycetes and these were observed in all the three conditions; Two species (Lentinussp and Coprines sp) were Basidiomycetes; one (Aspergillus sp) was Ascomycetes, Thefungal succession appeared in the saw dust showed that first fungal colonizers cause brownrot decay followed by white rot. Saw dust exposed to the fungal growth in laboratoryconditions showed the highest weight loss (42,86%) at the end of the study periodcompared with the weight loss observed in green house conditions and in laboratoryconditions,

It is clear that these fungal species have the ability to degrade complex cellulose and ligninmolecules to simple compounds. Due to the fungal activity, weight and strength of the sawdust were reduced, and the texture changed. This showed that there is a possibility ofusing saw dust as a growing medium, after its deterioration by suitable fungi,