Scale-up and kinetic modeling for bioethanol production

Area of Science:

• Biotechnology
• Chemical Engineering
• Microbiology

Background:

• Rice hulls are a lignocellulosic biomass source for sustainable bioethanol production.
• Scaling up bioethanol fermentation from laboratory to industrial levels presents significant challenges.
• Recombinant Escherichia coli KO11 is a suitable microorganism for efficient bioethanol synthesis.

Purpose of the Study:

• To optimize bioethanol production from rice hull hydrolysate via scale-up and kinetic modeling.
• To evaluate scale-up methodologies (constant Reynolds number, impeller tip speed) for bioreactor design.
• To validate modified Monod and Luedeking-Piret models for predicting fermentation performance.

Main Methods:

• Step-wise scale-up of bioethanol fermentation from 100 mL shaken flasks to 10 L stirred-tank bioreactors.
• Application of constant Reynolds number and constant impeller tip speed as scale-up criteria.
• Fermentation using recombinant Escherichia coli KO11 with acidic hydrolysate of rice hulls.
• Kinetic modeling using modified Monod and Luedeking-Piret equations.

Main Results:

• Volumetric bioethanol productivity increased by 88% in the 10 L bioreactor compared to shaken flasks (0.21 g L(-1) h(-1)).
• Maximum ethanol concentration reached 29.03 g/L in the 10 L bioreactor, closely matching model predictions (5% higher).
• Modified Monod and Luedeking-Piret models accurately represented the experimental fermentation data.

Conclusions:

• Successful scale-up of bioethanol production from rice hulls is achievable using Escherichia coli KO11.
• Constant impeller tip speed and Reynolds number are effective scale-up parameters for bioreactor design.
• Kinetic modeling provides a reliable tool for predicting and optimizing industrial-scale bioethanol fermentation from lignocellulosic feedstocks.