Butanol is considered to be a better biofuel than ethanol because it’s less corrosive and has a higher energy value. As previously noted, the production of bio-butanol nonetheless needs to be cost effective, if there is to be greater adoption of butanol as an alternative fuel.
And, not only does production need to be cost effective, but it also needs to be environmentally friendly. With the majority of butanol now made from fossil fuels, such production results in twice the amount of CO2 in comparison to ethanol. Thus, anaerobic fermentation would seem to be indicated for the production of butanol for transportation or industrial purposes.
Green Car Congress reports that California-based Cobalt Biofuels plans to produce biobutanol from a diverse range of non-food feedstocks, and has raised $25 million in equity to accelerate the commercialization of its cost-effective biochemical process for biobutanol production.
With feedstock diversity, Cobalt Biofuels can site its facilities in a wide range of geographies and use the feedstock available locally. Their technology allows for efficient matching of organisms to each regionally appropriate feedstock. A high-throughput process that can identify the optimal microbe for any selected plant substrate, according to the company has the advantage of reduced production cost and increased environmental sustainability.
Instead of using a typical batch fermentation process, Cobalt is developing and patenting key production monitoring technologies that will poise a continuous fermentation process at peak production rates for extended periods of time. By combining this approach with the microbial physiology and genetic engineering expertise, Cobalt says that it can substantially increase the rate of alcohol fuel production, thereby reducing production cost.
The concentration of biofuel, or titer, in the fermentation steep determines the cost of the energy intensive separation process. Cobalt’s uses a patented vapor compression distillation (VCD) fluid separation technology that removes alcohol from the fermentation steep using one-fourth the energy required for typical separation techniques. The titer also determines the overall water usage of the biorefinery. Cobalt’s technology has the additional advantage of reducing water usage by recycling the VCD-purified water back into the process with a substantial reduction in the overall water requirement.
More at Technology Review.