17963: Recycling of cellulases in high dry matter hydrolysis and SSF

Inbicon has for nearly a decade focused on developing a process for production of bioethanol from biomass. The result is the Inbicon process where biomass is converted into ethanol, animal feed (C5 molasses) and solid biofuel (lignin). For this purpose Inbicon has two pretreatment pilot plants (100 kg/h and 1000 kg/h) and a demonstration plant for conversion of 4 tons of wheat straw per hour. One of the unique features of the process is that the content of water insoluble solids (WIS) is between 25 and 40 % in all process streams.

In a second generation bioethanol process, the cost of enzymes is among one of the largest operating costs. Different strategies to minimize the enzyme consumption is therefore of utmost importance to make bioethanol cost competitive. One option is by recycling the cellulase enzymes. In the Inbicon process, cellulases can for instance be recovered from the thin stillage after separation of the solid biofuel with or without chemical modifications prior to separation. In this study, initial results on recycling of cellulases after hydrolysis and SSF of pretreated wheat straw at 25 % WIS will be presented.

SDS-gel page and enzyme activity techniques are used to quantify the presence of individual enzyme components during the time of hydrolysis and recycling.