Saccharification of polysaccharide content of palm kernel cake using enzymatic catalysis for production of biobutanol in acetone–butanol–ethanol fermentation

• Palm kernel cake (PKC) was pretreated by liquid hot water (LHW).
• LHW–pretreated PKC was hydrolyzed by β-glucosidase, cellulase and mannanase.
• The highest quantity of the total monomeric sugars liberated was 97.81 ± 1.29 g/L.
• Maximum butanol and ABE obtained were 4.15 ± 1.18 and 7.12 ± 2.06 g/L, respectively.
• Structural change in traded PKC was studied by scanning electron microscope and FTIR.

In this work, hydrolysis of cellulose and hemicellulose content of palm kernel cake (PKC) by different types of hydrolytic enzymes was studied to evaluate monomeric sugars released for production of biobutanol by Clostridium saccharoperbutylacetonicum N1-4 (ATCC 13564) in acetone–butanol–ethanol (ABE) fermentation. Experimental results revealed that when PKC was hydrolyzed by mixed β-glucosidase, cellulase and mannanase, a total simple sugars of 87.81 ± 4.78 g/L were produced, which resulted in 3.75 ± 0.18 g/L butanol and 6.44 ± 0.43 g/L ABE at 168 h fermentation. In order to increase saccharolytic efficiency of enzymatic treatment, PKC was pretreated by liquid hot water before performing enzymatic hydrolysis. Test results showed that total reducing sugars were enhanced to 97.81 ± 1.29 g/L with elevated production of butanol and ABE up to 4.15 ± 1.18 and 7.12 ± 2.06 g/L, respectively which represented an A:B:E ratio of 7:11:1.

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