Of enzyme use in cost-effective high solid simultaneous saccharification and fermentation processes.

Area of Science:

• Biotechnology
• Biochemical Engineering
• Industrial Microbiology

Background:

• Enzyme cost is a major factor in lignocellulose hydrolysis and fermentation economics.
• Enzyme immobilization and recycling offer a strategy to reduce these costs.
• Efficient recovery of immobilized enzymes from high solid loading broths is crucial but often overlooked.

Purpose of the Study:

• To evaluate the economic feasibility of using immobilized enzymes in lignocellulose biomass processing.
• To assess the recovery and recycling efficiency of magnetic immobilized enzymes (m-CLEAs) under high solid loading conditions in simultaneous saccharification, detoxification, and fermentation (SSDF).

Main Methods:

• Enzyme cost analysis using published data.
• Experimental investigation of m-CLEA recovery from liquid and thick broths.
• Development of a mathematical model to compare immobilized and free enzyme costs.
• Case study on lactic acid fermentation from lignocellulose substrate.

Main Results:

• Inoculum recirculation and shortened fermentation time decreased enzyme product price by 15%.
• Over 99.5% m-CLEA recovery was achieved in one step, with 88% recyclability from high solid concentration broths.
• Mathematical modeling indicated potential cost reductions of ~60% with immobilized enzymes at current efficiencies and commercial prices.

Conclusions:

• Enzyme immobilization can significantly reduce processing costs, but economic feasibility is sensitive to enzyme production costs and recovery efficiency.
• Shifting to lignocellulose substrates for processes like lactic acid fermentation requires optimized immobilized enzyme performance and recovery for viability.