One piece of the puzzle

2nd May, 2008

Enzyme development is progressing aggressively and costs are decreasing, yet more work needs to be done before biomass-based biofuels are a commercially-viable reality

Today, all projects focusing on ethanol production from cellulosic feedstocks experience very basic problems with feedstock collection, processing and high treatment costs. Although enzyme cost has been viewed as the major barrier to biomass conversion, this is no longer the case. That said, enzyme improvements are still required to achieve an economically viable process.

It is true that enzymes are still one of the biggest cost contributors for the production of second generation ethanol.

However, over the past five years, scientists have reduced enzyme costs significantly by employing new and improved enzyme systems, cheaper and more efficient enzyme production, and overall process improvements. This work continues and further cost reductions in this area is expected, yet it is important to note that cellulases and hemicellulases are complex enzyme systems and biomass is an especially complex substrate –work still needs to be done to optimise the process.

The enzymes that break down biomass

A key platform for making ethanol from biomass is the biochemical conversion process. Biomass is first pretreated by thermal, chemical, and mechanical processes to make cellulose accessible to enzymes.

Cellulase enzymes then deconstruct the cellulose, releasing glucose which can then be fermented to ethanol by biological organisms such as yeast. In order to efficiently break down cellulose, a mixture of several proteins with different activities is required.

Click here to subscribe to Biofuels International now!