title: Ethanol production from cotton gin trash using optimised dilute acid pretreatment and whole slurry fermentation processes.
abstract: Cotton ginning trash (CGT) collected from Australian cotton gins was evaluated for bioethanol production. CGT composition varied between ginning operations and contained high levels of extractives (26-28%), acid-insoluble material (17-22%) and holocellulose (42-50%). Pretreatment conditions of time (4-20 min), temperature (160-220 °C) and sulfuric acid concentration (0-2%) were optimised using a central composite design. Response surface modelling revealed that CGT fibre pretreated at 180 °C in 0.8% H2SO4 for 12 min was optimal for maximising enzymatic glucose recoveries and achieved yields of 89% theoretical, whilst the total accumulated levels of furans and acetic acid remained relatively low at <1 and 2 g/L respectively. Response surface modelling also estimated maximum xylose recovery in pretreated liquors (87% theoretical) under the set conditions of 150 °C in 1.9% H2SO4 for 23.8 min. Yeast fermentations yielded high ethanol titres of 85%, 88% and 70% theoretical from glucose generated from: (a) enzymatic hydrolysis of washed pretreated fibres, (b) enzymatic hydrolysis of whole pretreated slurries and (c) simultaneous saccharification fermentations, respectively.
authors.affiliation: NSW Department of Primary Industries, Wollongbar Primary Industries Institute, NSW, Australia.
authors.forename: S
authors.initials: S
authors.lastname: McIntosh
authors.affiliation: NSW Department of Primary Industries, Wollongbar Primary Industries Institute, NSW, Australia. Electronic address: tony.vancov@dpi.nsw.gov.au.
authors.forename: T
authors.initials: T
authors.lastname: Vancov
authors.affiliation: NSW Department of Primary Industries, Wollongbar Primary Industries Institute, NSW, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Palmer
authors.affiliation: NSW Department of Primary Industries, Wollongbar Primary Industries Institute, NSW, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Morris
mesh_terms: D000383:Agriculture / Q000379:methods; D001315:Australia; D001673:Biodegradation, Environmental; D000431:Ethanol / Q000737:chemistry*; D003368:Gossypium / Q000737:chemistry* / Q000382:microbiology*; D007220:Industrial Waste / Q000517:prevention & control*; D012037:Refuse Disposal / Q000379:methods*; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D013464:Sulfuric Acids / Q000737:chemistry*
chemical_list: D007220:Industrial Waste; D012722:Sewage; D013464:Sulfuric Acids; D000431:Ethanol; C033158:sulfuric acid
keywords: Cotton gin trash; Ethanol fermentations; Pretreatment optimisation