Cellulolytic Fungi and the Bioconversion of Fiber from Agave sisalana

Abstract

Agave sisalana, a plant thriving in semi-arid regions of Thailand, is an important source of fiber for the sisal and handicraft industries of the country. Isolations of 94 soil and plant samples from agave plantations in 3 provinces revealed 52 fungal isolates with cellulolytic activities on both Czapex' dox with a filter paper and CMC agar media. These isolates were propagated in a liquid medium at 30, 37 and 45°C. The fungal isolate with the highest cellulolytic activity (FP = 0.274 U/ml at 37°C) was identified as Acrophialophora sp. At 45°C, the fungus also grew and produced detectable cellulolytic activity, while Trichoderma reesei did not. Bioconversion using the simultaneous saccharification and fermentation (SSF) involving T. reesei and Saccharomyces cerevisiae gave the highest ethanol yield of 0.30 g/g. Preliminary tests on SSF using Acrophialophora sp. and S. cerevisiae gave the maximum ethanol yields of 0.11 g/g and 0.17 g/g with agave fiber and filter paper, respectively.