Two-Stage Pretreatment Process Validation for Production of Ethanol from Cotton Gin Trash
This study reports on the evaluation of a two-stage pretreatment process for preparing cotton gin trash (CGT) for conversation to ethanol. During the first stage, CGT was mixed with acid at 12% H2SO4 on solids and heated to 180 °C for 15 min in a pressurised stirred reactor. Pressed first-stage pretreated fibres were heated to 200 °C for 5 min during the second stage. The two-stage process facilitated excellent sugar recovery from both cellulose (84%) and hemicellulose (78%) fractions of CGT. Recombinant yeast GSF335 propagated on first-stage liquors yielded 41.8 g kg−1 of dry CGT and was compared with the commercial yeast during separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentations (SSF). SHF of pretreated CGT fibre yielded the equivalent of 66.2 and 64.0 kg ethanol per tonne of unprocessed CGT with GSF335 and the commercial yeast, respectively. SSF ethanol yields for the commercial yeast were significantly lower (50.3 kg) while GSF335 correspondingly produced 63.8 kg ethanol per tonne of raw CGT.
KeywordsCotton gin trash Ethanol fermentation Two-stage pretreatment C5 yeast propagation
The work was undertaken as part of the Biorefineries for Profit project which was funded by the Sugar Research Australia (SRA) and the Australian Government Department of Agriculture and Water Resources through the Rural R&D for Profit Program and Queensland Government Department of Agriculture and Fisheries, Cotton Research and Development Corporation, Forest and Wood Products Australia, Australian Pork Limited, Southern Oil Refining, Queensland University of Technology and NSW Department of Primary Industries, Australia. We express our gratitude to Yarraman Gin (Namoi Cotton Co-operative Ltd., NSW Australia) for supplying cotton-ginning residues.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
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