초록
<P><B>Abstract</B></P> <P>This paper reports on mild acid pretreatment options for the conversion of <I>Agave tequilana</I> leaves into composite sugars for ethanol fermentation. The effect of five different pretreatment conditions (time, temperature and acid concentrations) were assessed in terms of cellulose digestibility, hemicellulose solubilisation and lignin content in leaves of 1.25 years old <I>A. tequilana</I> plants from Rockhampton and 2.5 year plants from Kalamia. Dilute acid pretreatment and enzyme saccharification of <I>A. tequilana</I> leaf bagasse significantly improved total glucose recovery. A recovery of 273mg/g (70% theoretical) was attained when the bagasse was pretreated with 2.0% H<SUB>2</SUB>SO<SUB>4</SUB> for 60min at 121°C and saccharified with 6% (w/w) CTec 2. <I>Saccharomyces cerevisiae</I> efficiently fermented crude <I>A. tequilana</I> bagasse and juice hydrolysates within 13h and 7h respectively, yielding up to 38.6g/L and 12.4g/L. This corresponds to glucose to ethanol conversion rate of 68 and 61% for <I>A. tequilana</I> leaf bagasse and juice, respectively. With further developments, including fermentation of C5 sugars and inulinase saccharification of juices (release of fructose), this process could deliver greater yields, reinforcing its potential as a biofuel feedstock.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pretreatment of <I>Agave tequilana</I> leaves with sulphuric acid was investigated. </LI> <LI> Optimal pre-treatment condition was identified. </LI> <LI> Enzymatic glucose conversion of 70% was achieved. </LI> <LI> Leaf bagasse was fermented with 68% glucose to ethanol conversion. </LI> <LI> Fresh <I>A. tequilana</I> leaf juice was fermented without addition of enzyme. </LI> </UL> </P>