High yield bio-butanol production by solvent-producing bacterial microflora

Area of Science:

• Microbiology
• Biotechnology
• Environmental Science

Background:

• Sewage sludge is a potential source for microbial consortia capable of producing valuable biochemicals.
• Identifying and characterizing butanol-producing bacteria is crucial for developing sustainable bioprocesses.

Purpose of the Study:

• To isolate and identify efficient butanol-producing bacterial microflora from hydrogen-producing sludge.
• To optimize medium composition and fermentation conditions for enhanced bio-butanol production.

Main Methods:

• Denaturing Gradient Gel Electrophoresis (DGGE) and 16s rDNA sequencing for microbial identification.
• Box-Behnken design and Response Surface Methodology (RSM) for medium optimization.
• Batch fermentation studies with varying substrate concentrations and pressurized fermentation.

Main Results:

• Four Clostridium species were identified as key butanol producers.
• Optimized conditions (60 g/L glucose, 0.516 g/L FeSO(4)·7H(2)O, 5.13 g/L yeast extract) yielded 12.4 g/L butanol.
• Butyric acid addition increased titer to 17.51 g/L, and pressurized fermentation reached 21.35 g/L with a 1.25 g/L-h rate.

Conclusions:

• Bacterial microflora from sewage sludge can be effectively utilized for bio-butanol production.
• Medium optimization and advanced fermentation strategies significantly enhance bio-butanol yield and productivity.