Inhibitors Compounds on Sugarcane Bagasse Saccharification: Effects of Pretreatment Methods and Alternatives to...

Area of Science:

• Biotechnology and Bioengineering
• Renewable Energy
• Biomass Conversion

Background:

• Bioethanol production faces challenges including inhibitor formation during pretreatment, high energy input, and overall costs.
• Sugarcane bagasse is a promising lignocellulosic feedstock for biofuel production.
• Effective pretreatment and hydrolysis are crucial for maximizing fermentable sugar yields.

Purpose of the Study:

• To investigate the effects of different pretreatment methods (NaOH, H2SO4, water) on sugarcane bagasse composition.
• To evaluate the impact of polymers, polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP), on saccharification efficiency and enzyme activity.
• To identify cost-effective strategies for enhancing bioethanol precursor yields.

Main Methods:

• Sugarcane bagasse was pretreated using alkaline (NaOH), acidic (H2SO4), and water-based methods.
• Analysis of inhibitor concentrations (phenols, acetic acid, formic acid, furan derivatives) in liquid fractions.
• Saccharification assays were performed on pretreated biomass with and without the addition of PEG or PVP, assessing glucose and xylose release.
• Enzyme activities (endoglucanase, xylanase) were measured in the presence of polymers.

Main Results:

• Alkaline pretreatment yielded the highest phenol concentration (3.3 g/L), while acid pretreatment released significant acetic acid (2.3 g/L). Water pretreatment released formic acid (0.02 g/L).
• Furan derivatives were not detected in any liquid fractions.
• Washing effectively removed phenols. Addition of 0.4% (w/v) PEG or PVP enhanced glucose and xylose release by 8-10% and 26-31%, respectively, even without washing.
• PEG and PVP significantly increased endoglucanase and xylanase activities by over 50%.

Conclusions:

• Different pretreatment methods release distinct inhibitors, with alkaline pretreatment generating the most phenols.
• Polymers like PEG and PVP are effective in enhancing biomass saccharification and enzyme activity, offering a promising strategy to reduce costs and improve bioethanol production efficiency.
• The use of polymers presents a viable approach to overcome pretreatment-related challenges and boost sugar yields from sugarcane bagasse.