Temperature dependent cellulase adsorption on lignin from sugarcane bagasse

Area of Science:

• Biotechnology
• Biochemical Engineering
• Renewable Energy

Background:

• Lignin, a major component of lignocellulosic biomass like sugarcane bagasse, can inhibit enzymatic hydrolysis by adsorbing cellulolytic enzymes.
• Understanding enzyme-lignin interactions is crucial for optimizing biofuel production processes.
• Sugarcane bagasse is a promising feedstock for cellulosic ethanol production.

Purpose of the Study:

• To investigate the effect of incubation temperature and lignin extraction method on the adsorption of cellulolytic enzymes.
• To determine optimal conditions for minimizing enzyme loss due to lignin adsorption.
• To provide insights into the efficiency of simultaneous saccharification and fermentation (SSF) and consolidated bioprocessing (CBP).

Main Methods:

• Cellulolytic enzymes from Trichoderma reesei and Aspergillus niger were incubated with lignin extracted from sugarcane bagasse using different methods (acid hydrolysis, enzyme hydrolysis).
• Enzyme adsorption was quantified at different temperatures (30°C and 45°C).
• Enzyme activity was measured to assess the extent of adsorption and its impact on hydrolysis.

Main Results:

• Enzyme adsorption onto lignin was inversely proportional to incubation temperature; higher temperatures led to greater adsorption.
• Lignin from acid-hydrolyzed bagasse caused complete adsorption of T. reesei enzymes at 45°C within 90 minutes.
• At 30°C, enzyme adsorption was minimal, and enzyme hydrolysis rates approached those at 45°C after extended incubation (168 hours).

Conclusions:

• Reducing incubation temperature is an effective strategy to minimize cellulolytic enzyme loss through adsorption onto lignin.
• Lower temperatures (30-32°C) are beneficial for SSF and CBP processes, reducing lignin-derived inhibition.
• The findings contribute to improving the economic viability of lignocellulosic biomass conversion.