MODELING BASED SCALE-UP FOR BIOETHANOL PRODUCTION

Abstract

Bioethanol was produced from synthetic xylose using Pichia stipitis as a microorganism (with this aim that it would be done with 2nd generation of bioethanol hydrolysate).in this work scale-up process from 1 L reactor to 5 L reactor is performed where constant oxygen mass transfer rate (kLa), constant tip speed (tm) and constant power per volume (P/V) were evaluated as scale up strategies under laboratory condition. Initially, the culture condition is optimized at the flask level. In a 250 ml flask with a 50 ml working volume of media, Pichia stipitis has been cultured and some studies have been done to optimize carbon and nitrogen sources. After getting the expected culture condition and product concentration. 1 L reactor was undertaken as a culture vessel and checked the culture in different RPMs on 0.1 vvm to see where it mimics the flask level condition. It was found that at 400 RPM 0.1 vvm the kLa is the best-performing kLa in a 1 L reactor with an ethanol yield (YE/S) 0.429 g/g & ethanol productivity 0.91 g/Lh. Scale-up strategies are selected which are constant kLa, Constant power per volume (P/V) & constant tip speed (vtip). Equations-based scale-up modeling has been done where vvm was taken as constant to get constant kLa, Constant power per volume (P/V) & constant tip speed (vtip) in the 5 L reactor. In 5 L bioreactor at 310 rpm kLa was found by the equation reported 15.84 (1/h) was close by to 17.6 (1/h) kLa which was found in 400 rpm in the 1 L bioreactor. By comparing with other scale-up strategies like constant p/v & vtip, its observed that the constant kLa scale-up strategy produces the best results with the highest ethanol yield (YE/S) 0.453 g/g & ethanol productivity 0.88 g/Lh.