7-78: Application of cell wall degrading enzymes in planta for biomass hydrolysis and biofuel production

A limitation in the lignocellulose ethanol production is the costs of biomass pretreatment and enzyme hydrolysis. Agrivida, Inc. has developed cell wall degrading (CWD) enzymes in planta to decrease these economic costs. To test the impact of the expressed enzymes on cellulose and hemicelluloses degradation in the plants, hydrolysis experiments involving a moderate chemical pretreatment (< 100 °C) followed by the enzymatic hydrolysis were done. The transgenic plants expressing one or more CWD enzymes were processed along with wild-type and transgenic control plants to screen and identify top biomass hydrolysis plant performers.  Our experiment data demonstrate that the transgenic plants expressing cellulose and hemicellulose degrading enzyme(s) can achieve higher cellulose and hemicellulose conversions of 85% and 65% while the control plants were only at 70% and 35% conversions. Simultaneous saccharification and fermentation (SSF) with Saccharomyces cerevisiae D5A of these transgenic plants showed improved ethanol production of 70% over the control plants. These results demonstrate in planta expression of cell wall degrading (CWD) enzymes can significantly lower the current lignocellulosic bioprocessing industry enzyme loadings costs.