Direct Saccharification and Fermentation for High Glucose and Ethanol Production from Non‐Detoxified Furfural Residue Without Any Pretreatment

Abstract

Furfural residue (FR) is utilized directly for bioethanol production without any pretreatment and detoxification. With only 10 FPU g−1 cellulase loading, the glucose yield of FR reached 86.4, 84.6 and 80.5% at solid loadings of 2, 10 and 20%, respectively. When FR is directly used for fermentation, the terminal ethanol concentration achieved at 41 and 57 g L−1 at solid loadings of 20% and 30% (w v−1), respectively. Washing with water enhanced the enzymatic hydrolysis and fermentation of FR. The terminal ethanol of furfural residue washed by 5 times water (WFR‐5) was 48 and 66 g L−1, higher than that from FR. The enhancement is mainly due to the removal of chemical inhibitors and increase of specific surface area. The scanning electron microscope (SEM) showed that FR contained fragmental structure, coarse surface and porous areas. Therefore, FR substrates represented good cellulase accessibility. It indicated that FR could be directly used for glucose and ethanol production without any further treatment. In addition, the quasi‐simultaneous enzymatic saccharification and combined fermentation (Q‐SSF) residues are characterized by fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG).

Enhanced Enzymatic Saccharification of Mixed Sawdust Wastes: Comparison of SPORL, Dilute Acid, Formic Acid, and Ethanol Organosolv Pretreatments

“…Enzymatic hydrolysis of pretreated sawdust was carried out in duplicates at 2% (w/v) as described previously [26][27]. Briefly, 1 g of pretreated sawdust and 50 mL of acetate buffer (pH=5.5) were placed in a 150 mL conical flask in a shaking incubator at 50°C and 200 rpm.…”

Techno‐economics of one‐stage and two‐stage furfural production integrated with ethanol co‐production from sugarcane lignocelluloses

“…Employing washing for solids detoxification requires large amounts of water that require substantial amounts of process energy for downstream removal and treatment, to meet environmental regulation requirements 17,21 . The need for removal of yeast inhibitors can be avoided by using inhibitor resistant yeast, 17,22 while the use of organic solvents for furfural separation can be replaced by using a vapor‐releasing reactor, followed by conventional furfural azeotropic steam distillation 10,23,24 .…”

“…9,18,20 Employing washing for solids detoxification requires large amounts of water that require substantial amounts of process energy for downstream removal and treatment, to meet environmental regulation requirements. 17,21 The need for removal of yeast inhibitors can be avoided by using inhibitor resistant yeast, 17,22 while the use of organic solvents for furfural separation can be replaced by using a vapor-releasing reactor, followed by conventional furfural azeotropic steam distillation. 10,23,24 In view of this, the present study aims to conduct techno-economic assessment of two-stage furfural production using a vapor releasing reactor and ethanol co-production employing industrially available yeast without the need for washing the pretreated solids prior to fermentation.…”