Energy from domestic refuse by enzymatic degradation of cellulosic fibre waste into sugars and ethanol: initial laboratory studies

Abstract

The search for commercially viable biogenic sources of transport fuel, such as ethanol, is now
a priority among developed countries. Sugar- and starch-containing crops currently support
mature industries producing ethanol by yeast fermentation. The potential of bulk plant
materials (biomass crops, agricultural wastes and domestic refuse) is enormous, but such
ligno-cellulosic compounds are difficult to degrade into simple sugar molecules. In the USA
and Canada, commercial development programmes are under way to develop new enzymatic
and fermentation technologies and to reduce process costs.
We investigated the potential of processed waste material derived from domestic refuse as a
source of simple sugars for conversion to ethanol. "Pure" cellulose was almost completely
degraded to reducing sugars by cellulase C0I3L, a mixed enzyme preparation, and by
Trichoderma viride cellulase, whereas enzymes from other fungal species performed less
well. T viride achieved less than I 0% (by weight) conversion of waste material to reducing
sugars in 2 hour incubations, whereas C013L cellulase gave sugar yields of up to 35%.
Extended incubation times gave little increase in yield. These results support the feedstock
potential of this material. Alternative techniques, such as pre-treatment with ferulic acid
esterase to improve the effectiveness of degradation, are discussed.