Ultrasound-assisted hydrolysis of sugarcane bagasse using cellulolytic enzymes by direct and indirect sonication

In this work was studied the enzymatic hydrolysis of non-treated sugarcane bagasse under direct and indirect sonication using cellulolytic enzymes produced by solid-state fermentation. Hydrolyzes were carried out using a high-intensity ultrasound probe system of 300 W cm−2 and 24 kHz. The effects of operational variables such as ultrasound intensity, pulse factor and enzyme concentration on the hydrolysis yield were investigated. Maximum yield of hydrolysis were 31.3 g kg−1 and 60.6 g kg−1 under direct and indirect sonication, respectively. The optimized condition for indirect sonication hydrolysis was enzyme concentration higher than 209.5 µl g−1, continuous ultrasound irradiation and ultrasound intensity of 60 W cm−2. The indirect ultrasound irradiation showed to be more promising technology to be used in enzymatic reaction due to its positive effects on hydrolysis yield.