초록
<P><B>Abstract</B></P> <P>We report enzyme hydrolysis of cellulose in unpretreated pericarp at a cellulase loading of 0.25FPU/g pericarp solids using a phenol tolerant <I>Aspergillus niger</I> pectinase preparation. The overall protein added was 5mg/g and gave 98% cellulose conversion in 72h. However, for double the amount of enzyme from <I>Trichoderma reesei</I>, which is significantly less tolerant to phenols, conversion was only 16%. The key to achieving high conversion without pretreatment is combining phenol inhibition-resistant enzymes (such as from <I>A. niger</I>) with unground pericarp from which release of phenols is minimal. Size reduction of the pericarp, which is typically carried out in a corn-to-ethanol process, where corn is first ground to a fine powder, causes release of highly inhibitory phenols that interfere with cellulase enzyme activity. This work demonstrates hydrolysis without pretreatment of large particulate pericarp is a viable pathway for directly producing cellulose ethanol in corn ethanol plants.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cellulose hydrolysis of corn pericarp is feasible without pretreatment. </LI> <LI> <I>A. niger</I> cellulases in pectinase enzyme fraction tolerate phenol inhibitors. </LI> <LI> Ground pericarp (0.84mm) releases more phenols than cracked pericarp (5.1mm). </LI> <LI> Phenols from ground pericarp strongly inhibit enzymatic hydrolysis of pericarp. </LI> </UL> </P>