Butanol production from thin stillage using Clostridium pasteurianum

Area of Science:

• Microbiology
• Biotechnology
• Biochemical Engineering

Background:

• Thin stillage, a byproduct of bioethanol production, contains valuable nutrients like glycerol.
• Butanol is a valuable biofuel and chemical feedstock.
• Efficient microbial production of butanol from waste streams is crucial for sustainable bioeconomy.

Purpose of the Study:

• To evaluate butanol production from thin stillage using Clostridium pasteurianum DSM 525.
• To determine the impact of initial pH and lactic acid content on butanol yield.
• To assess the potential of thin stillage as a cost-effective fermentation medium.

Main Methods:

• Fermentation of thin stillage by Clostridium pasteurianum DSM 525 at varying initial pH (5.0-7.0).
• Analysis of butanol concentration, glycerol consumption, and lactic acid utilization.
• Measurement of pH changes during fermentation.

Main Results:

• Clostridium pasteurianum DSM 525 produced 6.2-7.2 g/L butanol from thin stillage.
• Butanol yields ranged from 0.32-0.44 g/g glycerol consumed, exceeding previously reported values.
• Lactic acid in thin stillage acted as a pH buffer and was co-utilized, enhancing butanol production from 6.5 g/L to 8.7 g/L.

Conclusions:

• Thin stillage is a suitable and cost-effective medium for microbial butanol production.
• Clostridium pasteurianum DSM 525 demonstrates high efficiency in converting thin stillage components to butanol.
• The inherent buffering capacity of thin stillage facilitates optimal fermentation conditions.