Liquefaction of sugarcane bagasse for enzyme production

• Submerged fermentation is made possible by liquefaction of biomass.
• Liquefaction gives a flowable slurry.
• Liquefied biomass is an effective fermentation media.
• Liquefied slurry gives 15× higher endoglucanase activity.

The objective of this paper is to report liquefaction of pretreated and sterilized sugarcane bagasse for enhancing endoglucanase production through submerged fermentation by Aspergillus niger. After initial solid state fermentation of steam pretreated bagasse solids by A. niger, fed-batch addition of the substrate to cellulase in buffer over a 12 h period, followed by 36 h reaction, resulted in a liquid slurry with a viscosity of 0.30 ± 0.07 Pa s at 30% (w/v) solids. Addition of A. niger for submerged fermentation of sterile liquefied bagasse at 23% w/v solids resulted in an enzyme titer of 2.5 IU mL−1 or about 15× higher productivity than solid-state fermentation of non-liquefied bagasse (final activity of 0.17 IU mL−1). Bagasse not treated by initial solid-state fermentation but liquefied with enzyme gave 2 IU mL−1. These results show the utility of liquefied bagasse as a culture medium for enzyme production in submerged fermentations.