title: Enzymatic hydrolysis and fermentation of pretreated cashew apple bagasse with alkali and diluted sulfuric Acid for bioethanol production.
abstract: The aim of this work was to optimize the enzymatic hydrolysis of the cellulose fraction of cashew apple bagasse (CAB) after diluted acid (CAB-H) and alkali pretreatment (CAB-OH), and to evaluate its fermentation to ethanol using Saccharomyces cerevisiae. Glucose conversion of 82 +/- 2 mg/g CAB-H and 730 +/- 20 mg/g CAB-OH was obtained when 2% (w/v) of solid and 30 FPU/g bagasse was used during hydrolysis at 45 degrees C, 2-fold higher than when using 15 FPU/g bagasse, 44 +/- 2 mg/g CAB-H, and 450 +/- 50 mg/g CAB-OH, respectively. Ethanol concentration and productivity, achieved after 6 h of fermentation, were 20.0 +/- 0.2 g L(-1) and 3.33 g L(-1) h(-1), respectively, when using CAB-OH hydrolyzate (initial glucose concentration of 52.4 g L(-1)). For CAB-H hydrolyzate (initial glucose concentration of 17.4 g L(-1)), ethanol concentration and productivity were 8.2 +/- 0.1 g L(-1) and 2.7 g L(-1) h(-1) in 3 h, respectively. Hydrolyzates fermentation resulted in an ethanol yield of 0.38 and 0.47 g/g glucose with pretreated CAB-OH and CAB-H, respectively. Ethanol concentration and productivity, obtained using CAB-OH hydrolyzate, were close to the values obtained in the conventional ethanol fermentation of cashew apple juice or sugar cane juice.
authors.affiliation: Departamento de Engenharia Química, Laboratório de Engenharia Bioquímica, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil. valponterocha@yahoo.com.br
authors.forename: Maria Valderez Ponte
authors.initials: MV
authors.lastname: Rocha
authors.forename: Tigressa Helena Soares
authors.initials: TH
authors.lastname: Rodrigues
authors.forename: Gorete Ribeiro
authors.initials: GR
authors.lastname: de Macedo
authors.forename: Luciana R B
authors.initials: LR
authors.lastname: Gonçalves
mesh_terms: D000468:Alkalies / Q000737:chemistry*; D031021:Anacardium / Q000378:metabolism*; D001628:Beverages / Q000382:microbiology*; D001709:Biotechnology / Q000379:methods; D002482:Cellulose / Q000378:metabolism; D004736:Energy-Generating Resources; D005285:Fermentation / Q000502:physiology*; D005947:Glucose / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013464:Sulfuric Acids / Q000737:chemistry*
chemical_list: D000468:Alkalies; D013464:Sulfuric Acids; D002482:Cellulose; C027433:bagasse; D005947:Glucose; C033158:sulfuric acid