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Updated: May 20, 2026

Evaluation of Integrated Anaerobic Digestion and Hydrothermal Carbonization for Bioenergy Production
Published on: June 15, 2014
Conversion of carbohydrates in herbaceous crops during anaerobic digestion
Annukka Pakarinen1, Maritta Kymalainen, Frederick L Stoddard
1Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland. annukka.z.pakarinen@helsinki.fi
Abstract:
The methane yields and conversion of pentoses (xylose) and hexoses (cellulose) in hemp, maize, and white lupin were studied over 30 days of anaerobic digestion. Preservation of hemp increased the methane yield by 23% compared with the fresh hemp. The increased methane yield of hemp was verified by the enhanced conversion of C6 sugars, increasing from 48% to about 70%, whereas the conversion of C5 sugars increased from only 9% to nearly 50%. The consumption of all carbohydrates in fresh maize was almost complete in the 30 days of anaerobic digestion. Hence, there was no major difference in carbohydrate consumption between fresh and preserved maize during biogas production. Fresh white lupin produced the highest methane yield (343 ± 33 dm(3) kg(-1) TS) in this work, mainly due to its highest amount of proteins. Conversion of C6 sugars was 80%, but that of C5 sugars was notably less at 46%.
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