Sequential Acid and Alkaline Pretreatment of Rice Straw for Bioethanol Fermentation
Pretreatment is a prerequisite step for increasing the enzymatic digestibility of agricultural residues for conversion to fuels and chemicals in biorefineries. In this study, a sequential acid and alkaline process was developed for pretreatment of rice straw for ethanol fermentation. Effects of key...
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| Format: | Article |
| Language: | English |
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North Carolina State University
2014-08-01
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| Series: | BioResources |
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| Online Access: | http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_09_4_5988_Weerasai_Sequential_Acid_Rice_Straw |
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| author | Khatiya Weerasai Nopparat Suriyachai Aphisit Poonsrisawat Jantima Arnthong Pornkamol Unrean Navadol Laosiripojana Verawat Champreda |
| author_facet | Khatiya Weerasai Nopparat Suriyachai Aphisit Poonsrisawat Jantima Arnthong Pornkamol Unrean Navadol Laosiripojana Verawat Champreda |
| author_sort | Khatiya Weerasai |
| collection | DOAJ |
| description | Pretreatment is a prerequisite step for increasing the enzymatic digestibility of agricultural residues for conversion to fuels and chemicals in biorefineries. In this study, a sequential acid and alkaline process was developed for pretreatment of rice straw for ethanol fermentation. Effects of key parameters in acid pretreatment were studied using a full factorial design model, which showed the higher influence of time compared to acid concentration and temperature on reducing sugar yields. The combined sequential process involved an initial hemicellulose solubilization by dilute acid using 1% (w/v) H2SO4 at 125 °C for 10 min, followed by alkaline delignification using 1.25% NaOH at 90 °C for 10 min. Under these conditions, a glucose recovery yield of 70.9% from saccharification of the cellulose enriched fraction was obtained with 2- to 4-fold savings in chemical usage as compared with single-step processes. Scanning electron microscopy revealed modification of biomass micro-structure and increases in reactive surface area. Simultaneous saccharification and fermentation of the solid residues by Saccharomyces cerevisiae, using 25 FPU/g Accellerase® 1500, led to a final ethanol concentration of 21.0 g/L with the productivity of 0.27 g/L/h, equivalent to 84.6% theoretical yield. The results indicate the potential of the sequential process for increasing pretreatment efficiency and allowing stepwise separation of lignocellulose components for multi-product biorefineries. |
| first_indexed | 2024-04-12T22:27:43Z |
| format | Article |
| id | doaj.art-dc20717a760444a48d03072881300bc5 |
| institution | Directory Open Access Journal |
| issn | 1930-2126 1930-2126 |
| language | English |
| last_indexed | 2024-04-12T22:27:43Z |
| publishDate | 2014-08-01 |
| publisher | North Carolina State University |
| record_format | Article |
| series | BioResources |
| spelling | doaj.art-dc20717a760444a48d03072881300bc52022-12-22T03:14:06ZengNorth Carolina State UniversityBioResources1930-21261930-21262014-08-01945988600110.15376/biores.9.4.5988-6001Sequential Acid and Alkaline Pretreatment of Rice Straw for Bioethanol FermentationKhatiya Weerasai0Nopparat Suriyachai1Aphisit Poonsrisawat2Jantima Arnthong3Pornkamol Unrean4Navadol Laosiripojana5Verawat Champreda6The Joint Graduate School for Energy and Environment (JGSEE), King Mongkut’s University of Technology Thonburi, Prachauthit Road, Bangmod, Bangkok 10140, ThailandThe Joint Graduate School for Energy and Environment (JGSEE), King Mongkut’s University of Technology Thonburi, Prachauthit Road, Bangmod, Bangkok 10140, ThailandNational Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Paholyothin Road, Klong Luang, Pathum Thani 12120, ThailandNational Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Paholyothin Road, Klong Luang, Pathum Thani 12120, ThailandBiochemical Engineering and Pilot Plant Research and Development Unit, National Center for Genetic Engineering and Biotechnology, King Mongkut's University of Technology Thonburi, Bangkhuntien, Bangkok 10150, ThailandThe Joint Graduate School for Energy and Environment (JGSEE), King Mongkut’s University of Technology Thonburi, Prachauthit Road, Bangmod, Bangkok 10140, Thailand National Center for Genetic Engineering and BiotechnologyPretreatment is a prerequisite step for increasing the enzymatic digestibility of agricultural residues for conversion to fuels and chemicals in biorefineries. In this study, a sequential acid and alkaline process was developed for pretreatment of rice straw for ethanol fermentation. Effects of key parameters in acid pretreatment were studied using a full factorial design model, which showed the higher influence of time compared to acid concentration and temperature on reducing sugar yields. The combined sequential process involved an initial hemicellulose solubilization by dilute acid using 1% (w/v) H2SO4 at 125 °C for 10 min, followed by alkaline delignification using 1.25% NaOH at 90 °C for 10 min. Under these conditions, a glucose recovery yield of 70.9% from saccharification of the cellulose enriched fraction was obtained with 2- to 4-fold savings in chemical usage as compared with single-step processes. Scanning electron microscopy revealed modification of biomass micro-structure and increases in reactive surface area. Simultaneous saccharification and fermentation of the solid residues by Saccharomyces cerevisiae, using 25 FPU/g Accellerase® 1500, led to a final ethanol concentration of 21.0 g/L with the productivity of 0.27 g/L/h, equivalent to 84.6% theoretical yield. The results indicate the potential of the sequential process for increasing pretreatment efficiency and allowing stepwise separation of lignocellulose components for multi-product biorefineries.http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_09_4_5988_Weerasai_Sequential_Acid_Rice_StrawAlkaline pretreatmentDilute acid pretreatmentEthanolLignocelluloseRice straw |
| spellingShingle | Khatiya Weerasai Nopparat Suriyachai Aphisit Poonsrisawat Jantima Arnthong Pornkamol Unrean Navadol Laosiripojana Verawat Champreda Sequential Acid and Alkaline Pretreatment of Rice Straw for Bioethanol Fermentation BioResources Alkaline pretreatment Dilute acid pretreatment Ethanol Lignocellulose Rice straw |
| title | Sequential Acid and Alkaline Pretreatment of Rice Straw for Bioethanol Fermentation |
| title_full | Sequential Acid and Alkaline Pretreatment of Rice Straw for Bioethanol Fermentation |
| title_fullStr | Sequential Acid and Alkaline Pretreatment of Rice Straw for Bioethanol Fermentation |
| title_full_unstemmed | Sequential Acid and Alkaline Pretreatment of Rice Straw for Bioethanol Fermentation |
| title_short | Sequential Acid and Alkaline Pretreatment of Rice Straw for Bioethanol Fermentation |
| title_sort | sequential acid and alkaline pretreatment of rice straw for bioethanol fermentation |
| topic | Alkaline pretreatment Dilute acid pretreatment Ethanol Lignocellulose Rice straw |
| url | http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_09_4_5988_Weerasai_Sequential_Acid_Rice_Straw |
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