title: Optimization of enzymatic hydrolysis and fermentation conditions for improved bioethanol production from potato peel residues.
abstract: The aim of this work was the optimization of the enzyme hydrolysis of potato peel residues (PPR) for bioethanol production. The process included a pretreatment step followed by an enzyme hydrolysis using crude enzyme system composed of cellulase, amylase and hemicellulase, produced by a mixed culture of Aspergillus niger and Trichoderma reesei. Hydrothermal, alkali and acid pretreatments were considered with regards to the enhancement of enzyme hydrolysis of potato peel residues. The obtained results showed that hydrothermal pretreatment lead to a higher enzyme hydrolysis yield compared to both acid and alkali pretreatments. Enzyme hydrolysis was also optimized for parameters such as temperature, pH, substrate loading and surfactant loading using a response surface methodology. Under optimized conditions, 77 g L-1of reducing sugars were obtained. Yeast fermentation of the released reducing sugars led to an ethanol titer of 30 g L-1after supplementation of the culture medium with ammonium sulfate. Moreover, a comparative study between acid and enzyme hydrolysis of potato peel residues was investigated. Results showed that enzyme hydrolysis offers higher yield of bioethanol production than acid hydrolysis. These results highlight the potential of second generation bioethanol production from potato peel residues treated with onsite produced hydrolytic enzymes. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:397-406, 2017.
authors.affiliation: Unité de recherche Sciences des Aliments, Ecole Supérieure des Industries Alimentaires de Tunis, Av Alain Savary, 58, Tunis, 1003, Tunisia.|Laboratoire de génies biologique et agroalimentaire, Université Libre de Tunis, Av Kheireddine Pacha, 30, Tunis, 1002, Tunisia.
authors.forename: Imen
authors.initials: I
authors.lastname: Ben Taher
authors.affiliation: Microbial Processes and Interaction, Gembloux AgroBioTech-Université de Liège, Passage des déportés, 2, Gembloux, 5030, Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Fickers
authors.affiliation: Université de Rennes 1, ENSCR, CNRS, UMR 6226, avenue du Général Leclerc, CS 50837, Rennes Cedex 7, 35708, France.
authors.forename: Sofien
authors.initials: S
authors.lastname: Chniti
authors.affiliation: Unité de recherche Sciences des Aliments, Ecole Supérieure des Industries Alimentaires de Tunis, Av Alain Savary, 58, Tunis, 1003, Tunisia.
authors.forename: Mnasser
authors.initials: M
authors.lastname: Hassouna
mesh_terms: D001234:Aspergillus niger / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018920:Coculture Techniques / Q000379:methods; D004798:Enzymes / Q000378:metabolism*; D000431:Ethanol / Q000302:isolation & purification / Q000378:metabolism*; D006868:Hydrolysis; D007220:Industrial Waste / Q000517:prevention & control; D010936:Plant Extracts / Q000737:chemistry*; D012037:Refuse Disposal / Q000379:methods; D011198:Solanum tuberosum / Q000737:chemistry* / Q000382:microbiology*; D014242:Trichoderma
chemical_list: D004798:Enzymes; D007220:Industrial Waste; D010936:Plant Extracts; D000431:Ethanol
keywords: bioethanol; enzymatic hydrolysis; potato peel residues; pretreatment; response surface methodology