This study reports results on the possibility of scale-up of ultrafiltration system for recovery of entomotoxicity components from Bacillus thuringiensis fermented wastewater/wastewater sludge broths. The wastewater/wastewater sludge comprised starch industry wastewater and hydrolyzed sludge. The study demonstrated that the optimal operational parameters, namely transmembrane pressure and feed flux for starch industry wastewater were 90 kPa and 550 L h(-1) m(-2), respectively. Likewise, the respective values for hydrolyzed sludge were 110 kPa and 720 L h(-1) m(-2). The loss in biological activity reported in terms of viable spores and soluble proteins was higher for hydrolyzed sludge due to higher viscosity and lower particle size. In the context of scale-up, dynamic resistance can serve as a key parameter which was reported to be higher for hydrolyzed sludge when compared to starch industry wastewater. Thus, starch industry wastewater will impose relatively less power input requirements and can be easily scaled-up. (C) 2009 Published by Elsevier B.V.