New feedstock and innovative transformation process for a more sustainable development and production of lignocellulosic ethanol
Summary
BABETHANOL will develop solutions for a more sustainable approach of 2nd generation renewable ethanol, based on a “moderate, environmental-friendly and integrated” transformation process that should be applicable to an expanded range of lignocellulosic feedstocks. The new process, called CES, will be an alternative to the costly processes of the state-of-the-art, notably to the current pre-treatments requiring much energy, water, chemical products, detoxification and waste treatment. CES will be developed and tested from laboratory to semi-industrial pilot-scale with different feedstocks. Life cycle assessment will be performed from input/output and services (energy, water and reagent consumptions) data generated by the design of industrial plants based on the new pretreatment developed during the project. A catalogue of lignocellulosic feedstocks from crops and agro-industrial residues available in South America and Western Europe and suitable for the new process will be developed during the project.
Four lignocellulosic materials selected for their expected potential for conversion to 2nd generation ethanol, have been fully characterized: Blue Agave Bagass (BAB) a fibrous residue resulting from the manufacturing of Tequila, Oil Palm Empty Fruit Bunches (OPEFB) another fibrous residue resulting from the manufacturing of palm oil, Sweet Corn (SC) a residue mixture resulting from the harvest of corn and the production of sweet corn, and Barley Straw (BS) a fibrous residue resulting from the harvest of barley.
 |
 |
 |
|
| BAB | OPEFB | SC | BS |
These materials have been used for the development of the new process at laboratory scale. Other potential feedstocks native in Latino America and Western Europe have been searched. Priority has been given to biomasses with specific chemical composition: cellulose >34%, hemicelluloses <30%, lignin <22%, ash<10%, lipids<10%, proteins<10% and not competing with human and animal feedings. Amounts available and geographical concentrations have been major selection criteria in order to be able to supply production plants of minimum 30000 tons per year processing capacity in regional/local level.
The study of the CES process at laboratory scale is well advanced: finished for BS, almost finished for SC and OPEFB and under progress for BAB. So far the best operating conditions for the destructuration part of the raw biomass have been determined (screw profile configuration, temperature and amount of catalyst). The optimum operating conditions are different for each biomass but within a small range of variation. Arrangements of conveying, compression and mixing screws are quite similar for each biomass. For the hydrolysis part, best cocktails of cellulases and hemicellulases have been selected from commercial products for each biomass. The fermentation of the hydrolysates is under study for each biomass. So far, the results are quite encouraging and simultaneous saccharification and fermentation seems to be a promising way to achieve ethanol production from the pretreated material. Best yeasts for the fermentation of C6 have been selected for each biomass. In-house C5+C6 yeasts are under development by to increase the alcohol production.
Preliminary industrial design and life cycle assessment have been performed from two different CES process configuration. The result of the LCA in terms of energy balance indicate that at least twice more energy must be produced from the overall process to get a competitive balance with first generation ethanol. This should be possible since in this preliminary industrial design only C6 sugar fermentation has been considered and extracts from the CES process which are rich in carbohydrates were not recycled. In terms of CO2 emission, the goal seems more difficult to achieve although there is room for improvement with, notably, the valorisation of some of the by-products from distillation.
The project aims to develop a new pretreatment for the production of 2nd generation ethanol that will provide a substantial cost reduction in comparison with current processes using other pretreatment of the state of the art such as acid hydrolysis. The new pretreatment will be especially adapted to small size production plants that can be located in rural or urban areas were crop or agro-industrial residues can be available respectively in amounts of at least 30000 tons per year. There should be many occurrences of this type of conditions in the countries studies for feedstock selection in the project, and therefore many opportunities for economical development and employment at regional/local level.
Contact list for the other partners of the project:
| Name | Contact person | |
| UNAM | Eduardo Bárzana | ebg@servidor.unam.mx |
| UCR | Julio Mata | julio.mata@ucr.ac.cr |
| INSA | Michael O’Donohue | michael.odonohue@insa-toulouse.fr |
| CIEMAT | Mercedes Ballesteros | m.ballesteros@ciemat.es |
| VTT | Jaana Uusitalo | jaana.uusitalo@vtt.fi |
| UNIUD-DiSA | Gian Paolo Vanozzi | gianpaolo.vannozzi@uniud.it |
| CMM | Carlos Mena-Brito | cmena@centromariomolina.org |
| APYGEC | Gérard Descamp | apygec@wanadoo.fr |
| CRT | Miguel Cruz Floriberto | floriberto.miguel@crt.org.mx |
| PROCAZUCAR | Federico López Medel | flopez@procazucar.com.mx |
| IICA-PROCISUR | Emilio Ruz Jerez | sejecutiva@procisur.org.uy |
| MAGUIN | Geneviève Doreau | genevieve.doreau@maguin.com |
