초록
<P><B>Abstract</B></P> <P>Switchgrass <I>(Panicum virgatum</I> L) is considered to be one of the best feedstocks for second generation ethanol production. However, its use as a biofuel resource for the ethanol market is challenged by high investment costs and inconsistent production methodologies. This study explores the use of switchgrass as a potential feedstock for ethanol production, investigating the effects of different pretreatment chemicals – sodium hydroxide, methanol, sulphuric acid and ammonia – employed at various concentrations of 0.5, 1 and 2 mol L<SUP>−1</SUP> on conversion yields, while also minimising cost and assessing potential environmental impacts.</P> <P>Glucose and ethanol yields showed that methanol was the most effective pretreatment chemical at 1 mol L<SUP>−1</SUP>, producing 230 g of glucose and 340 cm<SUP>3</SUP> of ethanol kg<SUP>−1</SUP> of feedstock with a 97% conversion rate. Pretreatment employing sodium hydroxide was found to be the least effective, with cellulose to glucose conversion rates of 38% and 62% following simultaneous saccharification and fermentation (SSF). In general, SSF significantly increased cellulose conversion rates, up to 32% for some samples. At 0.55 € kg<SUP>−1</SUP> glucose and 0.50 € L<SUP>−1</SUP> ethanol methanol was also found to be the most cost effective pretreatment technique compared to sodium hydroxide at 1.96 € kg<SUP>−1</SUP> glucose and 7.94 € L<SUP>−1</SUP> ethanol.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Switchgrass (<I>Panicum virgatum</I> L) is a native North American perennial grass which is considered to be one of the best feedstocks for ethanol production due to its high annual biomass yield and high carbohydrate content. </LI> <LI> Methanol was determined to be the most effective pretreatment chemical, compared to sodium hydroxide which was the least effective. </LI> <LI> Optimal pretreatment concentration was found to be 1 mol L<SUP>−1</SUP>, which produced higher conversion yields than those pretreated at 0.5 mol L<SUP>−1</SUP> and 2 mol L<SUP>−1</SUP>. </LI> <LI> Simultaneous, saccharification and fermentation (SSF) significantly increased conversion yields. Methanol pretreated switchgrass achieved conversion yields of 69% (glucose) and 97% (ethanol). </LI> <LI> Methanol was identified as the most environmentally friendly pretreatment chemical and the least costly (0.50 € L<SUP>−1</SUP>) when evaluated at the optimum concentration of 1 mol L<SUP>−1</SUP>. </LI> </UL> </P>