title: Ultrasound-assisted production of biodiesel and ethanol from spent coffee grounds.
abstract: This study evaluates the production of biodiesel and ethanol from spent coffee grounds (SCG). The extraction of oil from SCG, biodiesel production and ethanol production processes were studied. The liquid-to-solid ratio and temperature were evaluated in the ultrasound-assisted extraction of the oil from SCG. The highest yield (12%) was obtained using 4 mL g(-1) liquid-to-solid ratio at 60°C for 45 min. The process to produce biodiesel showed a yield of 97% into fatty acid methyl esters (FAME). The highest glucose yield (192 mg g SCG(-1)) was obtained by hydrolysis with 0.4 mol L(-1) sulfuric acid at 121°C for 15 min. The hydrolysate was used as fermentation medium for ethanol production by Saccharomyces cerevisiae obtaining 19.0 g L(-1) at 10h of process of ethanol with a yield of ethanol and productivity of 0.50 g g(-1) and 1.90 g L(-1)h(-1), respectively. Spent coffee grounds were considered a potential feedstock for biodiesel and ethanol production.
authors.affiliation: Universidade Federal do Ceará, Departamento de Engenharia Química, Fortaleza, CE, Brazil. Electronic address: valponterocha@yahoo.com.br.
authors.forename: Maria Valderez Ponte
authors.initials: MV
authors.lastname: Rocha
authors.affiliation: Universidade Federal do Ceará, Departamento de Engenharia Química, Fortaleza, CE, Brazil.
authors.forename: Leonardo José Brandão Lima
authors.initials: LJ
authors.lastname: de Matos
authors.affiliation: Universidade Federal do Ceará, Departamento de Engenharia Química, Fortaleza, CE, Brazil.
authors.forename: Larissa Pinto de
authors.initials: LP
authors.lastname: Lima
authors.affiliation: Universidade Federal Rural do Semiárido, Departamento de Agrotecnologia e Ciências Sociais, Mossoró, RN, Brazil.
authors.forename: Pablo Marciano da Silva
authors.initials: PM
authors.lastname: Figueiredo
authors.affiliation: Universidade Federal Rural do Semiárido, Departamento de Agrotecnologia e Ciências Sociais, Mossoró, RN, Brazil.
authors.forename: Izabelly Larissa
authors.initials: IL
authors.lastname: Lucena
authors.affiliation: Universidade Federal do Ceará, Departamento de Engenharia Química, Fortaleza, CE, Brazil.
authors.forename: Fabiano André Narciso
authors.initials: FA
authors.lastname: Fernandes
authors.affiliation: Universidade Federal do Ceará, Departamento de Engenharia Química, Fortaleza, CE, Brazil.
authors.forename: Luciana Rocha Barros
authors.initials: LR
authors.lastname: Gonçalves
mesh_terms: D056804:Biofuels; D003069:Coffee / Q000737:chemistry*; D000431:Ethanol / Q000378:metabolism*; D006868:Hydrolysis; D009821:Oils / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013816:Thermodynamics; D014465:Ultrasonics / Q000379:methods*; D014866:Waste Products
chemical_list: D056804:Biofuels; D003069:Coffee; D009821:Oils; D014866:Waste Products; D000431:Ethanol
keywords: Biodiesel; Ethanol; Fatty acid; Spent coffee ground; Ultrasound