Advanced BioFuels USA

by Alexander A. Koukoulas0 (ANL Consultants LLC/Biofuels Digest)  … The pursuit of 2^nd Gen fuels has been motivated by several factors including: their inherently low-cost, at least from a theoretical standpoint; their potential for drastically reducing carbon emissions relative to 1^st Gen Fuels; national security (less dependence on foreign oil); and job creation, especially in our rural communities. In retrospect, given the state of technology, the goal of delivering 2^nd Gen fuels as outlined in the Energy Policy Act of 2005 was certainly bold in its vision.

Unfortunately, while progress has been made in the last decade, 2^nd Gen fuels, especially those produced from biochemical platforms, have yet to achieve commercial viability due to their inability to be price competitive with either petroleum-derived fuels or conventional (1^st Gen) biofuels. In fact, several years ago, researchers and developers alike recognized these technical challenges and began shifting their focus from lignocellulosic ethanol to “drop-in” fuels, such bio-butanol, in the hope that enhanced compatibility with the existing liquid fuels infrastructure would make these fuels more cost competitive. In contrast, certain thermochemical approaches are seeing commercial opportunities and many projects are poised for success.

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To better understand the current state of biochemical-based production pathways, we reviewed recent developments in the production of 2^nd Gen biofuels produced under a number of biochemical routes. Our intent was to provide a state-of-the-art assessment of progress of advanced biofuels within three market segments: gasoline, middle distillates and aviation fuels ….

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What we found was that in spite of the significant progress made in the genetic engineering of microbes designed for advance biofuel production, titer and yield of these biomolecules are currently too low to allow these products to compete with their petroleum-derived equivalents.

What surprised us was how far off we are relative to corn-based ethanol.

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And, unlike yeast and conventional ethanol fermentation, recycling of microbial cells are difficult in a lignocellulosic system and genetically engineered strains seem highly susceptible to contamination, which further increases operating costs.

Of course, upstream challenges with cellulosic ethanol are not completely solved either. Recovery of sugars at high concentration from a highly water-holding (hydrophilic) substrate is still challenging. And, the downstream challenges with fermentation are multi-fold including: the toxicity of the inhibitors to both microbes and enzymes; conversion of multiple sugars; and, enzyme and microbe recycling of the enzymes.

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The question of inhibitors still presents an on-going challenge. As is well known, along with the presence of multiple sugars, lignocellulosic hydrolysates contain a spectrum of compounds, which are potentially toxic to the enzymes and/or microbes used in the bioconversion process.

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The potential for expanding 1^st Gen ethanol as a fuel and as a feedstock for chemicals production is enormous. In most cases, commercialization hurdles are a question of policy rather than technical readiness. However, with respect to 2^nd Gen biofuels, only a renewed commitment to basic R&D can provide the tools needed to bridge the many technical gaps that stand between the current state and commercial success. Clearly, the need to fund R&D programs will be a difficult argument to make given the current economic and political climate. But, it is possible if a broad, strategic view is taken. The alternative—widespread defunding of programs—will be a huge set-back. As for commercial opportunities, given this analysis, only value-added specialty chemicals—those that are differentiated from their petroleum analogues—have the potential to be commercially viable at least in the short run.  READ MORE