Mushroom spent straw: a potential substrate for an ethanol-based biorefinery

Area of Science:

• Biomass Pretreatment
• Renewable Energy
• Biorefining

Background:

• Rice straw (RS) is abundant lignocellulosic biomass, crucial for biorefineries but requires pretreatment due to recalcitrance.
• Ammonia Fiber Expansion (AFEX) is an effective thermochemical pretreatment, but further optimization is needed for RS.
• Fungal pretreatment offers a biological alternative, though often limited by sugar loss and time.

Purpose of the Study:

• To investigate the synergistic effect of fungal conditioning followed by AFEX pretreatment on rice straw.
• To optimize pretreatment severity and enhance enzymatic hydrolysis yields.
• To explore the recovery of valuable byproducts from the fungal pretreatment process.

Main Methods:

• Rice straw was pretreated using white-rot fungi (Pleutorus ostreatus) followed by AFEX pretreatment.
• Enzymatic hydrolysis was performed to assess sugar yields, specifically glucan conversion.
• Optimized conditions for fungal conditioning and AFEX were evaluated.

Main Results:

• Fungal conditioning of RS prior to AFEX reduced the required severity of thermochemical treatment.
• This combined pretreatment strategy resulted in a 15% increase in glucan conversion compared to AFEX alone.
• The study demonstrated the feasibility of integrating fungal pretreatment with AFEX for improved biomass processing.

Conclusions:

• Combining fungal pretreatment with AFEX offers a more efficient method for processing recalcitrant rice straw.
• This integrated approach enhances glucan conversion, crucial for biofuel and biochemical production.
• Further research into byproduct recovery from fungal conditioning can improve biorefinery economics.