초록
<P><B>Abstract</B></P> <P>The present work investigated the potential of acidogenesis digestate rich in volatile fatty acids (Bio-D<SUB>Acid</SUB>) and methanogenesis digestate rich in ammonia (Bio-D<SUB>Meth</SUB>) as a green method for the pretreatment of rice straw and biomethane production. After pretreatment with Bio-D<SUB>Meth</SUB> for 48 h, a maximum hemicellulose reduction of 22.4% was recorded, while 48 h of Bio-D<SUB>Acid</SUB> showed the lowest reduction of 15.7%. In addition, pretreatment for 48 h with Bio-D<SUB>Meth</SUB> and Bio-D<SUB>Acid</SUB> showed significant removal of lignin by 16.6 and 11.0%, respectively. SEM and FTIR confirmed major increase in straw porosity and degradation after all applied pretreatments. The highest significant biomethane content of 71.2% was recorded in 24 h Bio-D<SUB>Acid</SUB>-pretreated straw. However, the highest significant yield of 249.1 L kg<SUP>−1</SUP> VS was recorded from the 48 h Bio-D<SUB>Meth</SUB>-pretreated straw, which was 9.8, 19.6, and 27.0% higher than 24 h Bio-D<SUB>Meth</SUB>-, 24 h Bio-D<SUB>Acid</SUB> and 48 h Bio-D<SUB>Meth</SUB>-treated straw, respectively. Importantly, pretreatment with Bio-D<SUB>Meth</SUB> for 24 h showed the highest estimated net bioenergy output of 7.37 GJ ton<SUP>−1</SUP> dry straw, which represented 28.6 and 0.13% increase over that of the control and 48 h Bio-D<SUB>Meth</SUB>-pretreated straw, respectively. The present study suggested application of Bio-D<SUB>Meth</SUB> for 24 h as an efficient eco-friendly pretreatment method for efficient AD of rice straw.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Rice straw was pretreated by liquid digestates. </LI> <LI> Acidogenesis and methanogenesis digestates (Bio-D<SUB>Acid</SUB> & Bio-D<SUB>Meth</SUB>) were used. </LI> <LI> Bio-D<SUB>Acid</SUB> (24 h) showed the highest biomethane content of 71.2%. </LI> <LI> Bio-D<SUB>Meth</SUB> (48 h) showed the highest biomethane yield of 249.1 L kg<SUP>−1</SUP> VS. </LI> <LI> Bio-D<SUB>Meth</SUB> (24 h) showed the highest net bioenergy output of 7.37 GJ ton<SUP>−1</SUP> dry straw. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>