Concentration of Alkaline Hydrogen Peroxide (AHP) Affects the Recycle of the Liquid Fraction in the Pre-treatment and Enzymatic Hydrolysis of Corn Stover

• Published in: Waste and biomass valorization Vol. 11; no. 11; pp. 6179 - 6188
• Main Authors: Alencar, Bárbara Ribeiro Alves, Vaz, Fernanda Leitão, Barbosa Neto, Adauto Gomes, Aquino, Katia Aparecida, Sampaio, Everardo Valadares de Sa Barretto, Menezes, Rômulo Simões Cezar, Dutra, Emmanuel Damilano
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-11-2020; Springer Nature B.V
• Subjects: Biofuels; Cellulose; Chemical compounds; Corn; Engineering; Environment; Environmental Engineering/Biotechnology; Fourier transforms; Hemicellulose; Hydrogen peroxide; Hydrolysis; Industrial Pollution Prevention; Lignin; Lignocellulose; Original Paper; Pretreatment; Production costs; Recycling; Renewable and Green Energy; Solubilization; Stover; Waste Management/Waste Technology; Recycle liquid fraction; Pre-treatment; Lignocellulosic biomass; Enzymatic hydrolysis
• ISSN: 1877-2641; 1877-265X
• DOI: 10.1007/s12649-019-00884-7

Pre-treatment is one of main economic and technological challenges to render feasible the production of biofuels and chemical compounds from lignocellulosic biomass. Alkaline hydrogen peroxide (AHP) is the most used pre-treatment and recycling of its liquid fraction can help reduce production costs. The effects of four AHP concentrations (1, 3.5, 5 and 7.5% v/v) on the recycling performance of the liquid fraction of pre-treated corn stover was evaluated for five consecutive cycles. Delignification rates increased with increasing AHP concentrations in the first cycle: 15, 26, 43 and 76% with 1, 3.5, 5 and 7.5% v/v H
2
O
2
, respectively. In the following cycles, the rates decreased linearly reaching less than 40% in the last two recycles. These delignification rates and hemicellulose solubilization were corroborated by spectroscopic analyses with Fourier transformation showing reductions in lignin and hemicellulose absorbance and increases in crystallinity indices. Considering the low delignification rates in the last two cycles, the pre-treated biomasses obtained until the third cycle were submitted to enzymatic hydrolysis at 1:10 solid–liquid ratio. The delignification rates affected the efficiency of the enzymatic hydrolysis at all AHP concentrations and all recycles. The highest AHP concentration (7.5% v/v) was required to efficiently remove lignin and solubilize hemicellulose, maintaining cellulose conversion into glucose greater than 50% up to three recycles. Therefore, the technology of recycling the liquid solution of AHP pre-treatment is recommended with high initial concentrations (7.5% v/v).
Graphic Abstract