Innovative methods to generate clean sugar stream from biomass feedstocks for efficient fermentation

Area of Science:

• Biomass Conversion and Bioenergy
• Biochemical Engineering
• Sustainable Chemistry

Background:

• Sorghum stalks are a promising lignocellulosic feedstock for biofuel production.
• Acid pretreatment of biomass generates inhibitory compounds, reducing enzymatic hydrolysis efficiency.
• Effective detoxification is crucial for maximizing sugar yields from pretreated biomass.

Purpose of the Study:

• To compare the efficiency of alkali and acid pretreatment methods for sorghum stalk biomass.
• To investigate the removal of inhibitory compounds generated during acid pretreatment.
• To optimize a detoxification process for enhanced sugar recovery.

Main Methods:

• Sorghum stalk biomass was pretreated using both acid and alkali methods.
• Enzymatic hydrolysis was performed on pretreated biomass to quantify sugar yields.
• Detoxification of acid-pretreated biomass was achieved using activated charcoal and a cation/anion exchange resin mixture (7:3 ratio at pH 2.7).

Main Results:

• Alkali pretreatment resulted in a significantly higher sugar yield (49.1 g sugar/g pretreated biomass) compared to acid pretreatment (12.3 g sugar/g pretreated biomass).
• Activated charcoal effectively removed inhibitory compounds like hydroxymethyl furfural (HMF) and furfural.
• The optimized resin mixture completely removed HMF, acetic acid, and formic acid with minimal sugar loss (<2%).

Conclusions:

• Alkali pretreatment is superior to acid pretreatment for sorghum stalk biomass conversion to sugars.
• Effective detoxification of acid-pretreated biomass is essential for efficient enzymatic hydrolysis.
• The developed detoxification method using activated charcoal and ion-exchange resins offers a viable strategy for industrial-scale biofuel production.