Bioenergy II: Bio-ethanol from municipal solid waste (MSW): The role of biomass properties and structures during the ethanol conversion process

Abstract

The emerging biofuel industry demands large amount of biomass feedstock. Although commercial ethanol has been produced from primary biomass sources such as corns, the global food crisis caused by the use of primary biomass has been raised. Thus, lignocellulosic biomass, known as second generation of biomass, has become a promising source for ethanol production. However, the more complex structure requires more advance technology. MSW with more than 60% of biodegradable composition, as one of the promising biomass sources has the potential benefits of replacing primary biomass and preventing environment from MSW pollution. In this paper, three major biodegradable municipal solid waste (BMSW) components: kitchen organic waste (KOW), green organic waste (GOW) and paper and card waste (PCW), are classified and characterised according to substrate composition, cellulose crystallinity, bulk density and particle size. The substrate composition indicates how much cellulose, lignin, hermicellulose each model waste has. The cellulose content shows the potential glucose/ethanol product yield. Other chemical composition such as lignin and hemicellulose indicates how easy of each model waste can be converted. These contents are also important information when selecting pretreatment methods and conversion process conditions in the following steps. Based on the comprehensive understanding of biomass structures and compositions, studies look into the effects of substrate properties (such crystallinity, presence of lignin and cellulose content on process performances during enzymatic hydrolysis adsorption. Results indicated how the adsorption process is affected by the substrate properties. This provides understanding of the role of substrate properties during enzyme-cellulose adsorption.