title: The Effect of Ionic Liquid Pretreatment on the Bioconversion of Tomato Processing Waste to Fermentable Sugars and Biogas.
abstract: Tomato pomace is an abundant lignocellulosic waste stream from industrial tomato processing and therefore a potential feedstock for production of renewable biofuels. However, little research has been conducted to determine if pretreatment can enhance release of fermentable sugars from tomato pomace. Ionic liquids (ILs) are an emerging pretreatment technology for lignocellulosic biomass to increase enzymatic digestibility and biofuel yield while utilizing recyclable chemicals with low toxicity. In this study, pretreatment of tomato pomace with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) was investigated. Changes in pomace enzymatic digestibility were affected by pretreatment time and temperature. Certain pretreatment conditions significantly improved reducing sugar yield and hydrolysis time compared to untreated pomace. Compositional analyses suggested that pretreatment primarily removed water-soluble compounds and enriched for lignocellulose in pomace, with only subtle changes to the composition of the lignocellulose. While tomato pomace was effectively pretreated with [C2mim][OAc] to improve enzymatic digestibility, as of yet, unknown factors in the pomace caused ionic liquid pretreatment to negatively affect anaerobic digestion of pretreated material. This result, which is unique compared to similar studies on IL pretreatment of grasses and woody biomass, highlights the need for additional research to determine how the unique chemical composition of tomato pomace and other lignocellulosic fruit residues may interact with ionic liquids to generate inhibitors for downstream fermentation to biofuels.
authors.affiliation: Department of Food Science and Technology, University of California, Davis, CA, USA.
authors.forename: Brittany J
authors.initials: BJ
authors.lastname: Allison
authors.affiliation: Department of Chemical and Biotechnology Engineering, University of Chile, Santiago, Chile.
authors.forename: Juan Canales
authors.initials: JC
authors.lastname: Cádiz
authors.affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, CA, USA.
authors.forename: Nardrapee
authors.initials: N
authors.lastname: Karuna
authors.affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, CA, USA.
authors.forename: Tina
authors.initials: T
authors.lastname: Jeoh
authors.affiliation: Department of Food Science and Technology, University of California, Davis, CA, USA. cwsimmons@ucdavis.edu.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Simmons
mesh_terms: D056804:Biofuels; D018533:Biomass; D002480:Cellulase / Q000737:chemistry; D005285:Fermentation; D006868:Hydrolysis; D052578:Ionic Liquids / Q000494:pharmacology; D008031:Lignin / Q000096:biosynthesis / Q000737:chemistry*; D018551:Solanum lycopersicum / Q000737:chemistry*; D017744:Medical Waste Disposal; D009005:Monosaccharides / Q000096:biosynthesis* / Q000737:chemistry; D013696:Temperature
chemical_list: D056804:Biofuels; D052578:Ionic Liquids; D017744:Medical Waste Disposal; D009005:Monosaccharides; C036909:lignocellulose; D008031:Lignin; D002480:Cellulase
keywords: 1-Ethyl-3-methylimidazolium acetate; Anaerobic digestion; Cellulase; Enzymatic hydrolysis; Lignocellulose; Tomato pomace