The University of Florida is seeking companies interested in implementing and commercializing a series of bacterial modifications that permit more efficient utilization of sugars derived from biomass. Biomass is plant material that can function as a source of sugars for fermentation into products such as ethanol or organic acids (e.g. succinic acid) that are used as building blocks for many organic chemicals. The first step needed to convert biomass with a large percentage of complex carbohydrates (such as cellulose) into usable sugars is to chemically break down the cellulose into smaller subunits before adding the bacterial biocatalysts that ferment the sugars into end products. One of the most cost-effective means to break down cellulose is to add a strong acid such as phosphoric or sulfuric acid to the biomass. However, acid pre-treatment of biomass creates an unwanted byproduct called furfural that slows down fermentation. University of Florida researchers have identified pathways in the bacteria that can be modified to greatly reduce the inhibitory effects of furfural. Bacteria that incorporate a series of modifications developed as a result of this work more effectively process sugars into end product.
Bacterial modifications to increase efficiency of fermentation of biomass to products such as ethanol and organic acids
- Makes biomass conversion more efficient, saving time and money
- Compatible with existing infrastructure, increasing the likelihood of adoption
- Removes an obstacle to widespread use of cellulosic biomass, expanding the potential market
In order for biomass to be converted into usable biofuel, it must undergo processing. The first major step is to break down the biomass into a state that supports fermentation of the sugars in the biomass. One method for pretreating biomass to start breaking down complex carbohydrates into a form that can be more completely used by bacterial biocatalysts is to add a strong acid into the biomass, usually sulfuric or phosphoric acid. However, furfural is a significant byproduct of this process, and it inhibits the growth and function of the bacterial biocatalysts used to ferment biomass. University of Florida researchers have identified a number of pathways inhibited by furfural and have made modifications to the bacterial biocatalysts to overcome the inhibitory effects of furfural. For example; experiments have demonstrated that over-expression of the enzyme NADH-dependent propanedioloxidoreductase (FucO) reduces furfural and further improves tolerance to furfural in the fermenting bacteria by 50 percent.