title: Steam pretreatment and fermentation of the straw material "Paja Brava" using simultaneous saccharification and co-fermentation.
abstract: Pretreatment, enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) of the South American straw material Paja Brava were investigated. Suitable process conditions for an SO₂-catalyzed steam pretreatment of the material were determined and assessed by enzymatic digestibility of obtained fiber slurries for 72 h at a water insoluble solids (WIS) content of 2%. The best pretreatment conditions obtained (200 °C, 5 min holding time and 2.5% SO₂) gave an overall glucose yield following enzymatic hydrolysis of more than 90%, and a xylose yield of about 70%. Simultaneous saccharification and co-fermentation of glucose and xylose (SSCF) of the pretreated material using the xylose-fermenting strain Saccharomyces cerevisiae TMB3400 was examined at WIS contents between 5% and 10%. In agreement with previous studies on other materials, the overall ethanol yield and also the xylose conversion decreased somewhat with increasing WIS content in the SSCF. In batch SSCF, the xylose conversion obtained was almost 100% at 5% WIS content, but decreased to 69% at 10% WIS. The highest ethanol concentration obtained for a WIS content of 10% was about 40 g/L, corresponding to a yield of 0.41 g/g in a fed-batch SSCF. The Paja Brava material has previously been found difficult to hydrolyze in a dilute-acid process. However, the SSCF results obtained here show that similar sugar yields and fermentation performance can be expected from Paja Brava as from materials such as wheat straw, corn stover or sugarcane bagasse.
authors.affiliation: Department of Chemical Engineering, Lund University, P.O. Box 124, 22100 Lund, Sweden.
authors.forename: Cristhian
authors.initials: C
authors.lastname: Carrasco
authors.forename: Henrique
authors.initials: H
authors.lastname: Baudel
authors.forename: Mauricio
authors.initials: M
authors.lastname: Peñarrieta
authors.forename: Carlos
authors.initials: C
authors.lastname: Solano
authors.forename: Leslie
authors.initials: L
authors.lastname: Tejeda
authors.forename: Christian
authors.initials: C
authors.lastname: Roslander
authors.forename: Mats
authors.initials: M
authors.lastname: Galbe
authors.forename: Gunnar
authors.initials: G
authors.lastname: Lidén
mesh_terms: D050260:Carbohydrate Metabolism; D002241:Carbohydrates; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D007218:Industrial Microbiology / Q000379:methods*; D008031:Lignin / Q000737:chemistry; D006109:Poaceae; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013227:Steam; D013458:Sulfur Dioxide / Q000737:chemistry; D014994:Xylose / Q000378:metabolism*
chemical_list: D002241:Carbohydrates; D013227:Steam; D013458:Sulfur Dioxide; C036909:lignocellulose; D000431:Ethanol; D008031:Lignin; D014994:Xylose; D005947:Glucose