Hydrolysis, Detoxification and Alcoholic Fermentation of Hemicellulose Fraction from Palm Press Fiber

• Published in: Waste and biomass valorization 2018-06, Vol.9 (6), p.957-968
• Main Authors: Brito, Philipe Luan, de Azevedo Ferreira, Crisley Mara, Silva, André Felipe Ferreira, Pantoja, Lílian de Araújo, Nelson, David Lee, dos Santos, Alexandre Soares
• Format: Article
• Language: English
• Subjects: Acetic acid; Activated carbon; Activated charcoal; Biofuels; Biorefineries; Byproducts; Charcoal; Detoxification; Engineering; Environment; Environmental Engineering/Biotechnology; Ethanol; Fermentation; Furfural; Hemicellulose; Hydrolysis; Hydroxymethylfurfural; Industrial Pollution Prevention; Original Paper; Phenolic compounds; Phenols; Polysaccharides; Pretreatment; Renewable and Green Energy; Response surface methodology; Sugar; Sulfuric acid; Waste Management/Waste Technology
• ISSN: 1877-2641; 1877-265X
• DOI: 10.1007/s12649-017-9882-4

The palm press fiber, resulting from the extraction of oil from the fruit of the oil palm ( Elaeis guineensis ) is an abundant agro-industrial co-product with a potential for development of biorefineries. This study evaluated the use of the hemicellulose fraction contained in the palm press fiber as a source of sugars for the production of bioethanol by Scheffersomyces stipitis . The optimal condition for hemicellulose hydrolysis, determined by response surface methodology, utilized 30% of dry biomass in 5% H 2 SO 4 at 121 °C for 60 min, and resulted in removal of 88.4% of this polysaccharide. The soluble fraction recovered after the acid pretreatment, called hemicellulosic hydrolyzate, contained 83 g L −1 of reducing sugars. The hydrolyzate also contained 12 g L −1 of acetic acid, 489 mg L −1 of furfural and 46 mg L −1 of 5-hydroxymethylfurfural. The detoxification of the hydrolyzate with activated charcoal, overliming and a combination thereof was evaluated for removal of unwanted byproducts. The best detoxification treatment reduced the concentrations of phenolic compounds and furfural present in the hemicellulosic hydrolyzate by 96% and 99%, respectively. S. stipitis NRRLY 7124 and S. stipitis CBS 6054 were tested for the fermentation of the hydrolyzate. The highest yield of ethanol, 0.33 g ethanol g sugar −1 , was obtained with the NRRLY 7124 strain in the fermentation of the hydrolyzate detoxified by overliming. An estimated production of 12.1 L of ethanol per ton of palm press fiber derived solely from the hemicellulosic fraction was achieved.