17-31: Production of lignocellulolytic enzymes using maize seeds

Production of enzymes for the digestion of lignocellulosic biomass is one of the most expensive steps in biofuel production. Agrivida is pioneering the use of plants as inexpensive, scalable production platforms for these enzymes. Seed-specific expression has several advantages over microbial expression; enzymes can accumulate at high levels, and seeds provide a stable storage environment.  We describe maize seed-specific expression of an endoxylanase and a cellobiohydrolase, both originally derived from fungi. Although both seed-expressed  enzymes can be used without further purification, they were easily extracted and purified, and demonstrated pH and temperature stability that was comparable to, or better than, the microbially-produced enzymes. When added as flour, seed-expressed enzymes digested pretreated corn stover with similar efficiency to the microbial enzymes. One enzyme, which is heavily glycosylated in its fungal host, was expressed without glycosylation in maize seed, yet maintained comparable activity to the microbially-produced enzyme.