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Acetone-butanol fermentation of marine macroalgae
Michael H Huesemann1, Li-Jung Kuo, Lindsay Urquhart
1Pacific Northwest National Laboratory, Marine Sciences Laboratory, 1529 West Sequim Bay Road, Sequim, WA 98382, USA. michael.huesemann@pnl.gov
Bioresource Technology
|January 27, 2012
Summary
Clostridium acetobutylicum efficiently ferments glucose and mannitol from kelp extracts. However, low solvent yields indicate challenges for economically viable industrial seaweed acetone-butanol fermentation.
Area of Science:
- Biotechnology
- Microbial Fermentation
- Renewable Resources
Background:
- Seaweed, particularly Saccharina spp., contains fermentable sugars like mannitol and laminarin.
- Acetone-butanol-ethanol (ABE) fermentation is a key biofuel production process.
- Optimizing microbial utilization of diverse carbon sources from biomass is crucial for sustainable biofuel production.
Purpose of the Study:
- To evaluate the fermentation of mannitol and kelp extracts by Clostridium acetobutylicum.
- To understand the substrate utilization patterns and solvent production efficiency.
Main Methods:
- Acetone-butanol fermentation using Clostridium acetobutylicum (ATCC 824).
- Fermentation substrates included mannitol, glucose, and aqueous kelp extracts (Saccharina spp.).
- Analysis of microbial growth, substrate consumption, and solvent yield.
Main Results:
- Clostridium acetobutylicum readily fermented both glucose and mannitol.
- Diauxic growth observed with glucose-mannitol mixtures, with glucose consumed first.
- Triauxic growth observed with kelp extract, utilizing free glucose, mannitol, and bound glucose (laminarin) after hydrolysis.
- Low butanol (0.12 g/g) and total solvent (0.16 g/g) yields were obtained.
Conclusions:
- Kelp extracts can be fermented by Clostridium acetobutylicum, but require enzymatic hydrolysis for polysaccharide breakdown.
- Current solvent yields are insufficient for economic feasibility of industrial seaweed ABE fermentation.
- Further research is needed to enhance microbial strains and fermentation processes for efficient seaweed biomass conversion.
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