Nutrient modulation based process engineering strategy for improved butanol production from Clostridium...

Area of Science:

• Biotechnology and Bioengineering
• Metabolic Engineering
• Industrial Microbiology

Background:

• Achieving high titers and productivities of butanol from microbial fermentation is crucial for its economic viability.
• Wild-type Clostridium acetobutylicum strains often exhibit limitations in butanol production efficiency.

Purpose of the Study:

• To develop and optimize a process engineering strategy for enhanced butanol production using wild-type Clostridium acetobutylicum.
• To maximize both butanol titer and productivity through a multi-stage approach.

Main Methods:

• Optimization of two distinct media formulations for biomass and butanol productivity.
• Design of a two-stage fed-batch process integrating optimized media attributes.
• Incorporation of magnesium limitation and calcium supplementation.
• Integration with gas stripping and modulation of feeding duration.

Main Results:

• A two-stage fed-batch process yielded a butanol productivity of 0.55 g/L/h and a titer of 13.1 g/L.
• Combined process modifications (magnesium limitation, calcium supplementation) increased titer to 16.5 g/L and productivity to 0.59 g/L/h.
• The final integrated process with gas stripping achieved a cumulative butanol titer of 54.3 g/L with a productivity of 0.58 g/L/h.

Conclusions:

• The developed process engineering strategy significantly enhances butanol production from wild-type Clostridium acetobutylicum.
• The findings demonstrate a viable pathway for developing industrially relevant butanol bioprocesses.
• Further optimization could lead to even higher titers and productivities for sustainable biofuel production.