Promising bioethanol processes for developing a biorefinery in the Moroccan sugar industry

In order to establish a cost-effective biorefinery in Moroccan sugar plants, the use of sugarcane bagasse and beet pulp to produce bioethanol is considered as a promising option. In fact, lately this efficient way of biomass conversion into bioethanol, which is a cleaner source of energy, has received a lot of interest. In this context, the main objective of the present paper is to conduct a comparative study between the most investigated processes of producing bioethanol from lignocellulosic biomass. This study has considered the technical, economical, and environmental criteria to select the most efficient processes for a large scale production. For each step of the studied process, the most efficient options have been selected. In the pretreatment step, the use of dilute sulfuric acid was selected as the best option followed by steam explosion method. In the hydrolysis step, dilute sulfuric acid was also adopted. Concerning the following step, co-culture fermentation using a respiratory mutant of Saccharomyces cerevisiae and Pichia stipitis has been found to give the best result. In the last step, conventional distillation process coupled with pervaporation has been chosen as the best way to produce high purity anhydrous ethanol; while molecular sieves and extractive distillation in dividing-wall columns using ethylene glycol was also considered as promising alternatives of the pervaporation process.