ISOLATION AND CHARACTERISATION OF CELLULOLYTIC AND PECTOLYTIC
MICROORGANISMS FROM NATURALLY DEGRADING SOLID WASTES
H.H.V.M. Sanjeevani and S. C. Wijeyaratne
Department of Botany, University of Sri Jayewardenepura.
Cellulolytic microorganisms were isolated from natural compost heaps,
using different media such as Duboo's cellulose, cellulose mineral salt,
cellulose agar, cellulose dextrin agar which contain cellulose as the
only carbon source. Using pectin agar medium, which contained pectin as
the only carbon source, pectolytic microorganisms were isolated.
Cellulolytic fungal genera isolated were Helminthosporium sp., Aspergillus
sp., Cephalosporium sp. and Gliocladium sp. There were only cellulolytic
actinomycetes (Steptomyces sp.) and one cellulolytic bacterium. Pectolytic
microorganisms isolated were species of Aspergillus, Penicillium, Mucor,
Yeast and a pectolytic bacterium. Cellulolytic and pectolytic enzyme activities
of isolated microorganisms were determined using cotton wool, carboxymethyl
cellulose (CMC) and pectin as substrates. Sugar produced by degradation
of substrates were determined by Somogyi-Nelson micro method. Highest
cotton wool degrading activity and CMCase activity were obtained from
Gram negative short rod bacterium (8.899x10-3 units of enzyme/5ml and
1.2892 units of enzyme/5ml respectively). Highest pectinase activity was
obtained from Penicillium sp. (ii) (0.0136 units of enzyme/5ml).
All isolated cellulolytic microorganisms showed high growth rate at 30
and 350C while most pectolytic microorganisms showed high growth rate
at 350C. Except for species of Gliocladium other cellulolytic microorganisms
showed high growth rate at acidic pH range (pH 4.5). Among pectolytic
microorganisms Penicillium sp. (I) and Aspergillus niger showed high growth
rates at pH 5.5. But Penicillium sp. (ii) and Aspergillus sp. (ii) showed
high growth rates at pH 6.5.
It was clear that these microorganisms have the ability to degrade complex
cellulose and pectin molecules to simple compounds but it may not be economical
as they showed relatively low capacity. However it would be possible to
develop a microbial mixture, using above types of native microorganisms
that may have a high potential for degradation of solid wastes.
Department of Forestry and Environmental Science,
of Sri Jayewardenepura,Sri Lanka. 1995-2000. All rights reserved.