Development of Low-cost Cellulase Production Process using Trichoderma reesei

While commercial cellulase enzymes used in industrial scale cellulosic ethanol plants has greatly improved over the past decade, they are still costly. The team of Simo Ellilä of Brasil Ltda aimed to develop a simple, cost-efficient cellulase production process that could be used locally at a Brazilian sugarcane refinery.

The team evaluated several low-cost industrial residues for cellulase production and found that soybean hulls had the most desirable characteristics. The team then engineered a Trichoderma reesei strain to secrete cellulase in the presence of repressing sugars, which enables it to use sugarcane molasses as a carbon source.

The team also added a heterologous β-glucosidase to improve the performance of the enzymes. Finally, an invertase gene from Aspegillus niger was also added into their strain to allow it to consume sucrose from sugarcane molasses directly. Cost analysis showed that the process provides a low-cost enzyme with good performance on pretreated sugarcane straw.

This study presents the possibility of producing well-performing cellulase at very low costs in Brazil using T. reesei. This system could provide an alternative to commercial cellulases.