초록
<P><B>Abstract</B></P> <P>In this study, microwave-assisted alkali and acid pretreated rice straw <I>were</I> used to improve fermentable sugar yield by enzymatic saccharification (ES) employing cellulolytic fungal strains and subsequent bioethanol production by using fermenting yeast. The cellulolytic fungal strains <I>Trichoderma reesei</I> NCIM 1052, 1186, 992, <I>T. reesei</I> ITCC 4025, 6413, <I>Aspergillus niger</I> ITCC 302, <I>A. acculeatus</I> ITCC 5078, <I>A. fumigates</I> ITCC 4768 and <I>Fusarium Solani</I> ITCC 6397 were used for enzymatic saccharification (ES) of acid/alkali pretreated rice straw to optimize the sugar recovery. <I>T. reesei</I> NCIM 1052 was found superior as compared to the other fungal strains in terms of FPase, CMCase activities, and reducing sugars yield from pretreated rice straw. The strains of <I>Saccharomyces cerevisiae</I> NCIM 3186, and <I>Pichia stipitis</I> NCIM 3499 were used for subsequent fermentation to produce bioethanol. The saccharification of alkali pretreated rice straw (2% v/w NaOH) by <I>T. reesei</I> NCIM 1052 resulted in the highest fermentable sugar yield (55.6 g/l) and ultimately, the higher ethanol concentration after 72 h of fermentation with <I>P. stipitis</I> NCIM 3499 (25.3 g/L) as compared to other yeast strains. This study also exhibits the high potential for economic generation of ethanol from rice straw.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An acid and alkali treated rice straw was used for increment of FS & bioethanol yield. </LI> <LI> An efficient fungal strain was screened for enhancing enzymatic saccharification. </LI> <LI> <I>T. reesei</I> NCIM 1052 was observed to produce higher fermentable sugar yield. </LI> <LI> <I>P. stipitis</I> NCIM 3499 was found to produce higher bioethanol yield. </LI> <LI> This novel approach can also be used for another crop residue including rice straw. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>