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Department of Botany, Faculty of Science, University of Khartoum, Sudan

ABSTRACT

Cellulolytic ability of 25 moulds recovered from Sudanese cotton fibre was explored in relation to its effect on the physical properties of the fibre. Extracellular digestion, by 13 moulds, of carboxymethyl cellulose (CMC), cellobiose, or raw cotton indicated that a Chuetomium (out of three Chaetomium species), Aspergillus nidulans and A. fumigatus (arranged in descending order) caused most rapid degradation of pure cotton fibre. The phytopathogens Cephalosporium sp. and Stemphylium sp. caused least degradation. Moulds that were the best CMC or cellobiose utilisers did not necessarily digest raw cotton substrate at the same rate. Bundle strength and elongation of fibre, two properties of yarn spinnability, were assessed by immersing raw cotton in metabolites of nine test lint moulds. Thielavia greatly weakened bundle strength whilst fibre elongation property was highly reduced by Cladosporium herbarum. Stemphylium sp., Aspergillus futnigutus, Thieluuia sp. and Trichoderma sp., arranged in descending order.