Recycling of Chrysoporthe cubensis enzymes to overcome the adsorption in lignin and to improve sugarcane bagasse saccharification

Abstract

Biomass enzymatic hydrolysis efficiency shows some limitations, such as the non-specific adsorption of enzymes in lignin. We evaluated the adsorption of proteins and enzymes from Chrysoporthe cubensis into alkaline and acid pretreated sugarcane bagasse, containing 8.1 and 33.8% of lignin, respectively. The data from Langmuir isotherm showed that at 4 °C, proteins were more adsorbed by acid-treated bagasse, 10.5 mg g−1, while higher adsorption affinity, 2.0 mL mg−1, was determined from alkali-treated bagasse. Similarly, under hydrolytic conditions (50 °C), higher amounts of proteins were adsorbed into acid-treated bagasse, confirming the predominant effect of lignin on protein adsorption. Enzymatic recycling rounds during alkali-treated bagasse saccharification showed that the addition of fresh substrate and enzymes promoted the higher release of glucose and xylose, 40.3 and 38.3 g L−1, respectively. However, the addition of only fresh substrates showed to be efficient for C. cubensis enzymes recovery and substrate hydrolysis, which reduces enzyme consumption and costs.