Green Fractionation Approaches for the Integrated Upgrade of Corn Cobs
Corn cob is an abundant agricultural residue worldwide, with high potential and interesting composition, and its valorization still needs to be studied. Selectively fractionating its structural components (hemicellulose, cellulose, and lignin), value-added products can be produced, eliminating waste...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-04-01
|
| Series: | ChemEngineering |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2305-7084/7/2/35 |
| _version_ | 1797605920793952256 |
|---|---|
| author | João Fialho Patrícia Moniz Luís C. Duarte Florbela Carvalheiro |
| author_facet | João Fialho Patrícia Moniz Luís C. Duarte Florbela Carvalheiro |
| author_sort | João Fialho |
| collection | DOAJ |
| description | Corn cob is an abundant agricultural residue worldwide, with high potential and interesting composition, and its valorization still needs to be studied. Selectively fractionating its structural components (hemicellulose, cellulose, and lignin), value-added products can be produced, eliminating waste. In this work, integrated fractionation approaches were developed and evaluated. First, an organosolv process was optimized (ethanol:water, 50:50, <i>w</i>/<i>w</i>). Then, as a comparative method, alkaline delignification (using NaOH, 1–2%) was also studied. The organosolv process allowed a significant delignification of the material (79% delignification yield) and, at the same time, a liquid phase containing a relevant concentration (14.6 g/L) of xylooligosaccharides (XOS). The resulting solid fraction, rich in cellulose, showed an enzymatic digestibility of 90%. The alkaline process increased the delignification yield to 94%, producing a solid fraction with a cellulose enzymatic digestibility of 83%. The two later techniques were also used in a combined strategy of hydrothermal processing (autohydrolysis) followed by delignification. The first allowed the selective hydrolysis of hemicellulose to produce XOS-rich hydrolysates (26.8 g/L, 67.3 g/100 g initial xylan). The further delignification processes, alkaline or organosolv, led to global delignification yields of 76% and 93%, respectively. The solid residue, enriched in glucan (above 75% for both combined processes), also presented high enzymatic saccharification yields, 89% and 90%, respectively. The fractionation strategies proposed, and the results obtained are very promising, enabling the integrated upgrading of this material into a biorefinery framework. |
| first_indexed | 2024-03-11T05:07:57Z |
| format | Article |
| id | doaj.art-5473d7fbbe6f4232b3164c4ec56ab4b8 |
| institution | Directory Open Access Journal |
| issn | 2305-7084 |
| language | English |
| last_indexed | 2024-03-11T05:07:57Z |
| publishDate | 2023-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | ChemEngineering |
| spelling | doaj.art-5473d7fbbe6f4232b3164c4ec56ab4b82023-11-17T18:44:18ZengMDPI AGChemEngineering2305-70842023-04-01723510.3390/chemengineering7020035Green Fractionation Approaches for the Integrated Upgrade of Corn CobsJoão Fialho0Patrícia Moniz1Luís C. Duarte2Florbela Carvalheiro3LNEG, Laboratório Nacional de Energia e Geologia, Unidade de Bioenergia e Biorrefinarias, Estrada do Paço do Lumiar, 22, 1649-038 Lisboa, PortugalLNEG, Laboratório Nacional de Energia e Geologia, Unidade de Bioenergia e Biorrefinarias, Estrada do Paço do Lumiar, 22, 1649-038 Lisboa, PortugalLNEG, Laboratório Nacional de Energia e Geologia, Unidade de Bioenergia e Biorrefinarias, Estrada do Paço do Lumiar, 22, 1649-038 Lisboa, PortugalLNEG, Laboratório Nacional de Energia e Geologia, Unidade de Bioenergia e Biorrefinarias, Estrada do Paço do Lumiar, 22, 1649-038 Lisboa, PortugalCorn cob is an abundant agricultural residue worldwide, with high potential and interesting composition, and its valorization still needs to be studied. Selectively fractionating its structural components (hemicellulose, cellulose, and lignin), value-added products can be produced, eliminating waste. In this work, integrated fractionation approaches were developed and evaluated. First, an organosolv process was optimized (ethanol:water, 50:50, <i>w</i>/<i>w</i>). Then, as a comparative method, alkaline delignification (using NaOH, 1–2%) was also studied. The organosolv process allowed a significant delignification of the material (79% delignification yield) and, at the same time, a liquid phase containing a relevant concentration (14.6 g/L) of xylooligosaccharides (XOS). The resulting solid fraction, rich in cellulose, showed an enzymatic digestibility of 90%. The alkaline process increased the delignification yield to 94%, producing a solid fraction with a cellulose enzymatic digestibility of 83%. The two later techniques were also used in a combined strategy of hydrothermal processing (autohydrolysis) followed by delignification. The first allowed the selective hydrolysis of hemicellulose to produce XOS-rich hydrolysates (26.8 g/L, 67.3 g/100 g initial xylan). The further delignification processes, alkaline or organosolv, led to global delignification yields of 76% and 93%, respectively. The solid residue, enriched in glucan (above 75% for both combined processes), also presented high enzymatic saccharification yields, 89% and 90%, respectively. The fractionation strategies proposed, and the results obtained are very promising, enabling the integrated upgrading of this material into a biorefinery framework.https://www.mdpi.com/2305-7084/7/2/35alkaliautohydrolysisdelignificationenzymatic hydrolysisorganosolv |
| spellingShingle | João Fialho Patrícia Moniz Luís C. Duarte Florbela Carvalheiro Green Fractionation Approaches for the Integrated Upgrade of Corn Cobs ChemEngineering alkali autohydrolysis delignification enzymatic hydrolysis organosolv |
| title | Green Fractionation Approaches for the Integrated Upgrade of Corn Cobs |
| title_full | Green Fractionation Approaches for the Integrated Upgrade of Corn Cobs |
| title_fullStr | Green Fractionation Approaches for the Integrated Upgrade of Corn Cobs |
| title_full_unstemmed | Green Fractionation Approaches for the Integrated Upgrade of Corn Cobs |
| title_short | Green Fractionation Approaches for the Integrated Upgrade of Corn Cobs |
| title_sort | green fractionation approaches for the integrated upgrade of corn cobs |
| topic | alkali autohydrolysis delignification enzymatic hydrolysis organosolv |
| url | https://www.mdpi.com/2305-7084/7/2/35 |
| work_keys_str_mv | AT joaofialho greenfractionationapproachesfortheintegratedupgradeofcorncobs AT patriciamoniz greenfractionationapproachesfortheintegratedupgradeofcorncobs AT luiscduarte greenfractionationapproachesfortheintegratedupgradeofcorncobs AT florbelacarvalheiro greenfractionationapproachesfortheintegratedupgradeofcorncobs |