Alkaline-sulfite pretreatment and use of surfactants during enzymatic hydrolysis to enhance ethanol production from sugarcane bagasse

Author(s)

Mesquita, Jessica Faria ^[1] ; Ferraz, Andre ^[2] ; Aguiar, Andre ^{[1, 3]}

Affiliation

^[1] Univ Fed Sao Joao Del Rei, Dept Quim Biotecnol & Engn Bioproc, Campus Alto Paraopeba, CP 131, BR-36420000 Ouro Branco, MG - Brazil

^[2] Univ Sao Paulo, Escola Engn Lorena, Dept Biotecnol, BR-12602810 Lorena, SP - Brazil

^[3] Univ Fed Itajuba, Inst Recursos Nat, CP 50, BR-37500903 Itajuba, MG - Brazil

• Document type: Journal article
• Source: Bioprocess and Biosystems Engineering; v. 39, n. 3, p. 441-448, MAR 2016.
• Web of Science Citations: 17

Abstract

Sugarcane bagasse is a by-product from the sugar and ethanol industry which contains approximately 70 % of its dry mass composed by polysaccharides. To convert these polysaccharides into fuel ethanol it is necessary a pretreatment step to increase the enzymatic digestibility of the recalcitrant raw material. In this work, sugarcane bagasse was pretreated by an alkaline-sulfite chemithermomechanical process for increasing its enzymatic digestibility. Na2SO3 and NaOH ratios were fixed at 2: 1, and three increasing chemical loads, varying from 4 to 8 % m/m Na2SO3, were used to prepare the pretreated materials. The increase in the alkaline-sulfite load decreased the lignin content in the pretreated material up to 35.5 % at the highest chemical load. The pretreated samples presented enhanced glucose yields during enzymatic hydrolysis as a function of the pretreatment severity. The maximum glucose yield (64 %) was observed for the samples pretreated with the highest chemical load. The use of 2.5 g l(-1) Tween 20 in the hydrolysis step further increased the glucose yield to 75 %. Semi-simultaneous hydrolysis and fermentation of the pretreated materials indicated that the ethanol yield was also enhanced as a function of the pretreatment severity. The maximum ethanol yield was 56 +/- 2 % for the sample pretreated with the highest chemical load. For the sample pretreated with the lowest chemical load (2 % m/m NaOH and 4 % m/m Na2SO3), adding Tween 20 during the hydrolysis process increased the ethanol yield from 25 +/- 3 to 39.5 +/- 1 %. (AU)

• FAPESP's process: 14/06923-6 - Sugar cane biomass recalcitrance: basic knowledge related to the cell wall construction, pretreatment and enzymatic digestion, applied for the development of innovative biorefinery models
• Grantee: Andre Luis Ferraz
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Thematic Grants
• FAPESP's process: 08/56256-5 - Topochemistry, porosity and chemical composition determining successful enzymatic sacarification of sugarcane bagasse
• Grantee: Adriane Maria Ferreira Milagres
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Thematic Grants