{"title":"Control of pH by CO <sub>2</sub> Pressurization for Enzymatic Saccharification of Ca(OH) <sub>2</sub> -Pretreated Rice Straw in the Presence of CaCO <sub>3</sub>.","authors":"Masakazu Ike, Ken Tokuyasu","doi":"10.5458/jag.jag.JAG-2019_0019","DOIUrl":null,"url":null,"abstract":"<p><p>The aim of this study was to investigate the effect of pH control by CO <sub>2</sub> pressurization on the enzymatic hydrolysis of herbaceous feedstock in the calcium capturing by carbonation (CaCCO) process for fermentable sugar production. The pH of the slurry of 5 % (w/w) Ca(OH) <sub>2</sub> -pretreated/CO <sub>2</sub> -neutralized rice straw could be controlled between 5.70 and 6.38 at 50 °C by changing the CO <sub>2</sub> partial pressure ( <i>p</i> CO <sub>2</sub> ) from 0.1 to 1.0 MPa. A mixture of fungal enzyme preparations, namely, <i>Trichoderma reesei</i> cellulases/hemicellulases and <i>Aspergillus niger</i> β-glucosidase, indicated that pH 5.5-6.0 is optimal for solubilizing sugars from Ca(OH) <sub>2</sub> -pretreated rice straw. Enzymatic saccharification of pretreated rice straw under various <i>p</i> CO <sub>2</sub> conditions revealed that the highest soluble sugar yields were obtained at <i>p</i> CO <sub>2</sub> 0.4 MPa and over, which is consistent with the expected pH at the <i>p</i> CO <sub>2</sub> without enzymes and demonstrates the effectiveness of pH control by CO <sub>2</sub> pressurization.</p>","PeriodicalId":14999,"journal":{"name":"Journal of applied glycoscience","volume":null,"pages":null},"PeriodicalIF":1.2000,"publicationDate":"2020-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/2b/11/JAG-67-059.PMC8294032.pdf","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of applied glycoscience","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.5458/jag.jag.JAG-2019_0019","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2020/1/1 0:00:00","PubModel":"eCollection","JCR":"Q4","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 1
Abstract
The aim of this study was to investigate the effect of pH control by CO 2 pressurization on the enzymatic hydrolysis of herbaceous feedstock in the calcium capturing by carbonation (CaCCO) process for fermentable sugar production. The pH of the slurry of 5 % (w/w) Ca(OH) 2 -pretreated/CO 2 -neutralized rice straw could be controlled between 5.70 and 6.38 at 50 °C by changing the CO 2 partial pressure ( p CO 2 ) from 0.1 to 1.0 MPa. A mixture of fungal enzyme preparations, namely, Trichoderma reesei cellulases/hemicellulases and Aspergillus niger β-glucosidase, indicated that pH 5.5-6.0 is optimal for solubilizing sugars from Ca(OH) 2 -pretreated rice straw. Enzymatic saccharification of pretreated rice straw under various p CO 2 conditions revealed that the highest soluble sugar yields were obtained at p CO 2 0.4 MPa and over, which is consistent with the expected pH at the p CO 2 without enzymes and demonstrates the effectiveness of pH control by CO 2 pressurization.