The development and characterization of new milliliter-scale stirred tank bioreactors for enzymatic hydrolysis on a 10 milliliter scale was achieved. A novel magnetically driven impeller (German Patent Application DE 20 2010 011 902.2) rotates freely on an axis in an unbaffled bioreactor. An efficient homogenization of the 48 parallel stirred tank bioreactors was shown at high solids loading (20 % w/w microcrystalline cellulose).
A reliable and robust scale up of the enzymatic hydrolysis process was successfully performed to the liter-scale based on the power consumption and mixing characteristics at milliliter-scale. This successful scale up was validated for enzymatic hydrolysis of lignocellulosic feedstock and microcrystalline cellulose mixtures by a commercial cellulase complex on both scales.