Biocarburants

Normand Gadoury, Enerkem

Robin Speer, Canadian Renewable Fuels Association

Curt Rich, an energy lawyer and lobbyist, represents advanced biofuel feedstock interests and project developers before the United States Congress and Federal agencies. His presentation will review current policies that serve to promote the biofuel industry in the United States and discuss new policies that will guide the industry forward in the coming years. He will provide an overview of the array of Federal tax incentives, grant programs and loan guarantees that are available to biofuel developers in the United States. He will conclude his presentation with an examination of how upcoming debates on energy, climate change and tax policy are likely to change the direction of the U.S. biofuel industry.

Curt Rich, Van Ness Feldman

Michael J. McAdams, Advanced Biofuels Association

Normand Gadoury, Enerkem

Marc-Antoine Demers, Ressources naturelles Canada

Blaine Kennedy, Technologies du développement durable du Canada

Given the heated discussion around biofuels, especially with respect to competition for land between food crops and energy crops, algae seem to have a lot of potential because they can be grown on marginal or non-arable lands. Moreover, their yields are much higher, such that a lot less land would be required to produce the same amount of biofuels.

The BC Innovation Council asked SeedScience, Inc. to conduct a study examining the feasibility of growing algae in BC to make biofuels. This six-month study examined a host of aspects concerning algae cultivation, oil extraction, species selection, yields, capital and operational costs. Three basic technologies were examined: the raceway, which is an open pond usually agitated by a paddle wheel; the photobioreactor, which is a sealed environment to cultivate specific algae strains inside plastic or glass tubes; and the fermenter, which grows algae anaerobically, using an organic carbon source.

The results of this study clearly rule out the photobioreactor as a biofuels technology based on its very high capital and operational costs. Due to the low insolation and rough climate in BC, as well as significant capital and operational costs, the raceway is also not deemed to be a feasible technology, although it may deliver fuels at a cost close to one dollar per litre in more southerly latitudes. The fermenter appears to be the most promising technology for northern climates since it combines very high yields with comparatively lower capital and operational costs.

All algae technologies face significant technical hurdles and uncertainties that need to be overcome through continued research and development. The possibility of producing a high-value byproduct can help achieve more favourable economics for algae to biofuel technologies. The market for such products, however, are often very limited and mass algae production could lead to major price reductions, which creates a lot of financial insecurity.

Although technically feasible, the economic challenges of producing biofuels from algae leave the authors skeptical about the future of this technology. A factor 10 or more in cost reductions is required and can only be achieved by combining a host of strategies and mastering several technical challenges in algae production. Alternatives, such as producing biofuels using bacteria or fungi, should also be explored and compared to algae as a biofuels feedstock.

Martin Tampier, ENVINT Consulting

Introduction. Energy crops were receiving a lot of attention lately, for the production of biofuels: ethanol, biodiesel and methane. There are currently large biorefineries for the production of ethanol from mostly corn and other cereals while pilot experiments are underway to use cellulosic crops and wood biomass 1. Another avenue worth looking into is the production of methane using anaerobic digestion from crops, since theoretical energy yield is higher with methane than ethanol 2. Energy crops, mainly corn silage and grass, are also commonly used on farms to increase the methane yield of the anaerobic digestion of organic wastes. Crops anaerobic digestion could also be used in a biorefinery directed toward purified methane production. As of now, the bioconversion efficiency is very high for starch crops and less interesting for cellulosic crops. The increase in methane yield for those crops will come from the application of efficient but cost-effective pre-treatments 3. The objective of this research was to evaluate the impact of a vast array of pre-treatments in order to increase the biodegradability of the crops and assess the specific methane production from the pre-treated crops.

Methodology. The pre-treatments tested were grinding, blending, chopping, sonication, microwave, alkalinization, heat, heat and pressure, and different enzymes. The pre-treatments were evaluated for their impact on the solubilization of the energy crops.

The specific activity for cellulose and xylose were tested on different inoculum in order to obtain competent biomass for an optimal degradation of the crops and subsequent methane generation. The inoculum tested were activated sludge, municipal anaerobic sludge, pulp and paper anaerobic sludge, agro-food wastewaters-treating anaerobic granules, rumen from calves, and a mix of agro-food granules and rumen. All inoculum degraded xylose within 24 or 48 hours of addition. However, only the mix granules-rumen was able to achieve the mineralization of cellulose into methane in 8 days (85% recovery in methane). This inoculum was then selected for all biomethane potential (BMP) assays 4. The best pre-treatments based on solubilization results, were then evaluated with BMP tests.

Results and discussion. The starch crops, corn kernels and potatoes, generated high amounts of methane in short incubation time (15 days), with relatively low intensity pre-treatment. The sonication of corn kernels increased the methane generation by 22% compared with grinding, from 326 to 397 L CH4 STP/kg TS. For the potatoes, the alkalinization increased the methane generation by only 13% compared with blending only, from 299 to 328 L CH4 STP/kgTS after 15 days. However, alkalinization increased very significantly the initial methane production: 75% of the total methane was already expressed within 2 days of incubation, which was 5 times faster than with blending only.

The lignocellulosic crops tested were corn silage and switchgrass. As expected, the pre-treatment retained for the methane potential assays, alkalinization coupled with heat and pressure, was more intensive than for the starch crops, in order to achieve a partial breakdown of the plants. Also, the incubation period were much longer, varying between 5 and 11 weeks. The corn silage produced more methane but benefited less from the pre-treatment, with a 12% methane increase (194 L CH4 STP/kgTS) compared with 22% for the switchgrass (127 L CH4 STP/kgTS). The switchgrass was obtained from a winter harvest and therefore dried. Further assays were performed with a summer harvest of switchgrass (fresh switchgrass), with better success.

The intensity of the mechanical pre-treatment of fresh switchgrass was very significant for the methane production, with a 120% increase with a blended mix (268 L CH4 STP/kgTS ) compared with simply chopped switchgrass (122 L CH4 STP/kgTS). The addition of a peroxidase enzyme from Coprinus did not improve the methane production from the blended sample (244 L CH4 STP/kgTS). The best results were obtained with a more intensive pre-treatment, alkalinisation, heat and pressure, yielding 377 L CH4 STP/kgTS, e.g. three times more methane.

More enzymes were tested with the summer switchgrass (fresh), after blending. The pectate-lyase improved the methane production by 40% over the control assay with 266 L CH4 STP/kgTS, while the poly-galacturonase improved the methane produced by 79%, at 230 L CH4 STP/kgTS. A mix of both enzymes did not provide a better yield, at 246 L CH4 STP/kgTS. Although these enzymes appear promising for increasing the methane yield from summer switchgrass, the enzyme loading required were high, and the incubation time was long (11 weeks). More improvment is needed.

The last set of assays verified the impact of the addition of lignin peroxidase (Li-P) and manganese peroxidase (Mn-P) on the methane production from summer switchgrass. These enzymes were used alone, or coupled with alkalinization. The addition of Li-P increased by 48% the methane generated at 189 L CH4 STP/kgTS compared with 128 L CH4 STP/kgTS for the control after 8 weeks of incubation. The use of Mn-P yielded 84% more methane, at 236 L CH4 STP/kgTS. The use of alkalinization prior to the addition of enzymes did not significantly contribute to the methane production with 230 and 243 L CH4 STP/kgTS for the Li-P and Mn-P assays, respectively.

Conclusion. The methane generation from energy crops represents an efficient method for bioenergy production, but further work is still necessary to combine physico-chemical and enzymatic pre-treatments in order to optimize the methane production from energy crops. The use of competent biomass, particularly cellulolytic bacteria, should also be considered for bioaugmentation of digesters.

References.
1 Amon T., B. Amon, V. Kryvoruchko, A. Machmüller, K. Hopfner-Sixt, V. Bodiroza, R. Hrbek, J. Friedel, E. Pötsch, H. Wagentristl, M. Schreiner, W. Zollitsch. 2007. Bioresource Techn. 98: 3204-12.
2 McKendry P. 2002. Bioresource Techn. 83: 37-46.
3 Hill J. 2007. Agron. Sustain. Dev., 27: 1-12.
4 Owen W.F., D.C. Stuckey, J.B. Healy, L.Y. Young, P.L. McCarty,1979. Water Res. 13: 485-492.

Serge R. Guiot, Institut de Recherches en Biotechnologie du CNRC

Marie-Hélène Labrie, Enerkem

Worldwide attention is focused on bioethanol production as a means to tackle current global warming and energy security concerns. However, feedstocks for current bioethanol production processes comprise food crops whose supplies have become increasingly constrained. To alleviate this pressure on food supply as demand for bioethanol increases, a pressing need exists to develop technologies that utilize the abundant lignocellulosic biomass obtained from non-food plants as well as inedible portions of food crops.

Corynebacterium glutamicum is widely used in the industrial production of amino and nucleic acids. By developing and utilizing C. glutamicum RITE strain, we successfully demonstrated high volumetric productivities of the growth-arrested cells packed to a high density in a reactor in a process we coined the "RITE bioprocess". In collaboration with private sectors, we aim for early industrial application of the RITE bioprocess in bioproducts production.

In this presentation, current advances on biofuels and biochemicals production at RITE will be discussed.

Haruhiko Teramoto, Research Institute of Innovative Technology for the Earth

Christophe Luguel, Pôle de Compétitivité Industries & Agro-Ressources