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Paper Mill Sludge as a Source of Sugars for Use in the Production of Bioethanol and Isoprene
- Source :
- Energies, Vol 13, Iss 4662, p 4662 (2020), Energies; Volume 13; Issue 18; Pages: 4662
- Publication Year :
- 2020
- Publisher :
- MDPI AG, 2020.
-
Abstract
- Paper mill sludge (PMS) solids are predominantly comprised of cellulosic fibers and fillers rejected during the pulping or paper making process. Most sludges are dewatered and discharged into landfills or land spread at a cost to the mill; creating large economic and environmental burdens. This lignocellulosic residual stream can be used as a source of sugars for microbial fermentation to renewable chemicals. The aim of this study was to determine the possibility of converting mill sludge to sugars and then fermentation to either isoprene or ethanol. Chemical analysis indicated that the cellulosic fiber composition between 28 to 68% and hemicellulose content ranged from 8.4 to 10.7%. Calcium carbonate concentration in the sludge ranged from 0.4 to 34%. Sludge samples were enzyme hydrolyzed to convert cellulose fibers to glucose, percent conversion ranged from 10.5 to 98%. Calcium carbonate present with the sludge resulted in low hydrolysis rates; washing of sludge with hydrochloric acid to neutralize the calcium carbonate, increased hydrolysis rates by 50 to 88%. The production of isoprene “very low” (190 to 470 nmol) because the isoprene yields were little. Using an industrial yeast strain for fermentation of the sludge sugars obtained from all sludge samples, the maximum conversion efficiency was achieved with productivity ranging from 0.18 to 1.64 g L−1 h−1. Our data demonstrates that PMS can be converted into sugars that can be fermented to renewable chemicals for industry.
- Subjects :
- Control and Optimization
020209 energy
Energy Engineering and Power Technology
Lignocellulosic biomass
02 engineering and technology
Sludge
lcsh:Technology
chemistry.chemical_compound
Hydrolysis
0202 electrical engineering, electronic engineering, information engineering
calcium carbonate
Hemicellulose
Electrical and Electronic Engineering
Engineering (miscellaneous)
lignocellulosic biomass
Isoprene
lcsh:T
Renewable Energy, Sustainability and the Environment
business.industry
food and beverages
sludge
hydrolysis
sugars
biofuels
Paper mill
021001 nanoscience & nanotechnology
Pulp and paper industry
Calcium carbonate
chemistry
Biofuel
Biofuels
Fermentation
Sugars
0210 nano-technology
business
Energy (miscellaneous)
Subjects
Details
- ISSN :
- 19961073
- Volume :
- 13
- Database :
- OpenAIRE
- Journal :
- Energies
- Accession number :
- edsair.doi.dedup.....2e586ea2eb4f266bdac80d858be46b30