Evoluted Proton-Assisted Cellulose Hydrolysis
The application of ethanol produced by feed-based substrates (cereals, sugar and molasses), as an alternative energy source (known as first-generation ethanol) does not constitute a solution for the medium/long term, due to the inflation that the increase in liquid fuel demand causes in the markets related to the food and feed.
Therefore, it is of strategic importance to develop technologically efficient and economically viable systems for the synthesis of sugars from inedible organic components or waste (second generation ethanol (2G)).
Sugarcane residues, including bagasse (SB) and straw (SS), represent the ideal raw material for the production of second generation ethanol being a renewable source of non-competitive carbohydrates compared to the food and feed.
These renewable raw materials are rich in carbohydrates (sugars) and today are not exploited by the industry, due to the compactness of the crystal structure in which they are contained (cellulose) that makes difficult the solubilization process necessary for the commercialization of cellulosic ethanol.
Access to sugars is hindered by the reluctance of plant cell walls. In particular the lignin, a complex aromatic polymer, encloses the cellulose in order to strengthen and protect the plant. Furthermore, most of the glucose in the lignocellulosic structure is locked in highly crystalline cellulose polymers. Finally, the hemicellulose is a branched polymer of glucose, xylose, and other sugars, which possess different energies of activation towards the degradation of the monomers.
The challenge lies in identifying and optimizing a treatment technology that allows to:
- Increase the production of sugar from renewable sources by non-enzymatic hydrolysis of cellulosic and hemicellulosic grating;
- The recovery of the lignin prior to the non-enzymatic hydrolysis stages;
- Prevent degradation and loss of carbohydrates during the extraction process;
- Prevent the formation of synthetic substances that inhibit the enzymatic fermentation of sugars extracted;
- Design this in an economically and environmentally sustainable way, which means: fast, low energy consumption, and using non-toxic or harmful to the environment.