title: Pretreatment of rice straw with combined process using dilute sulfuric acid and aqueous ammonia.
abstract: BACKGROUND
  Use of lignocellulosic biomass has received attention lately because it can be converted into various versatile chemical compounds by biological processes. In this study, a two-step pretreatment with dilute sulfuric acid and aqueous ammonia was performed efficiently on rice straw to obtain fermentable sugar. The soaking in aqueous ammonia process was also optimized by a statistical method.
  
  
  RESULTS
  Response surface methodology was employed. The determination coefficient (R(2)) value was found to be 0.9607 and the coefficient of variance was 6.77. The optimal pretreatment conditions were a temperature of 42.75°C, an aqueous ammonia concentration of 20.93%, and a reaction time of 48 h. The optimal enzyme concentration for saccharification was 30 filter paper units. The crystallinity index was approximately 60.23% and the Fourier transform infrared results showed the distinct peaks of glucan. Ethanol production using Saccharomyces cerevisiae K35 was performed to verify whether the glucose saccharified from rice straw was fermentable.
  
  
  CONCLUSIONS
  The combined pretreatment using dilute sulfuric acid and aqueous ammonia on rice straw efficiently yielded fermentable sugar and achieved almost the same crystallinity index as that of α-cellulose.
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seoul, 136-701, South Korea.
authors.forename: Sung Bong
authors.initials: SB
authors.lastname: Kim
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seoul, 136-701, South Korea.
authors.forename: Sang Jun
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seoul, 136-701, South Korea.
authors.forename: Ju Hun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seoul, 136-701, South Korea.
authors.forename: You Ree
authors.initials: YR
authors.lastname: Jung
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seoul, 136-701, South Korea.
authors.forename: Laxmi Prasad
authors.initials: LP
authors.lastname: Thapa
authors.affiliation: Department of Chemical Engineering, Kyonggi University, Suwon 443-760, South Korea.
authors.forename: Jun Seok
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 136-791, South Korea.
authors.forename: Youngsoon
authors.initials: Y
authors.lastname: Um
authors.affiliation: Department of Chemical Engineering, Kwangwoon University, Seoul 139-701, South Korea.
authors.forename: Chulhwan
authors.initials: C
authors.lastname: Park
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seoul, 136-701, South Korea.
authors.forename: Seung Wook
authors.initials: SW
authors.lastname: Kim
keywords: Dilute acid pretreatment; Pretreatment; Response surface methodology; Rice straw; Soaking aqueous ammonia
references.citation: Bioresour Technol. 2009 Oct;100(19):4374-80
references.pmid: 19427784
references.citation: Carbohydr Res. 2011 Jan 3;346(1):103-10
references.pmid: 21129736
references.citation: Bioresour Technol. 2009 Jan;100(1):10-8
references.pmid: 18599291
references.citation: Appl Biochem Biotechnol. 2008 Mar;148(1-3):71-81
references.pmid: 18418741
references.citation: Bioresour Technol. 2008 Sep;99(13):5694-702
references.pmid: 18248985
references.citation: Bioresour Technol. 2011 Oct;102(19):8992-9
references.pmid: 21784629
references.citation: Bioresour Technol. 2011 Nov;102(21):10028-34
references.pmid: 21903384
references.citation: Bioresour Technol. 2010 Jul;101(13):4851-61
references.pmid: 20042329
references.citation: Appl Biochem Biotechnol. 1996 Apr;59(1):39-51
references.pmid: 8651681
references.citation: Bioresour Technol. 2008 Jun;99(9):3817-28
references.pmid: 17826088
references.citation: Appl Microbiol Biotechnol. 2004 Nov;66(1):10-26
references.pmid: 15300416
references.citation: Bioresour Technol. 2003 Oct;90(1):39-47
references.pmid: 12835055
references.citation: J Microbiol Biotechnol. 2007 Dec;17(12):1996-2004
references.pmid: 18167448
references.citation: Bioresour Technol. 2011 Feb;102(3):2916-24
references.pmid: 21134742