Feedstock/pretreatment screening for bioconversion of sugar and lignin streams via deacetylated disc-refining.

Recent publications have shown the benefits of deacetylation disc-refining (DDR) as a pretreatment process to deconstruct biomass into sugars and lignin residues. Major advantages of DDR pretreatment over steam and dilute acid pretreatment are the removal of acetyl and lignin during deacetylation. DDR does not generate hydroxymethylfurfural (HMF) and furfural which are commonly produced from steam and dilute acid pretreatments.

Characterization of pilot-scale dilute acid pretreatment performance using deacetylated corn stover.

Background: Dilute acid pretreatment is a promising process technology for the deconstruction of low-lignin lignocellulosic biomass, capable of producing high yields of hemicellulosic sugars and enhancing enzymatic yields of glucose as part of a biomass-to-biofuels process. However, while it has been extensively studied, most work has historically been conducted at relatively high acid concentrations of 1 - 4% (weight/weight). Reducing the effective acid loading in pretreatment has the potential to reduce chemical costs both for pretreatment and subsequent neutralization.

Improved ethanol yield and reduced minimum ethanol selling price (MESP) by modifying low severity dilute acid pretreatment with deacetylation and mechanical refining: 2) Techno-economic analysis.

Background: Our companion paper discussed the yield benefits achieved by integrating deacetylation, mechanical refining, and washing with low acid and low temperature pretreatment. To evaluate the impact of the modified process on the economic feasibility, a techno-economic analysis (TEA) was performed based on the experimental data presented in the companion paper.

Results: The cost benefits of dilute acid pretreatment technology combined with the process alternatives of deacetylation, mechanical refining, and pretreated solids washing were evaluated using cost benefit analysis within a conceptual modeling framework.

Enzymatic conversion of xylan residues from dilute acid-pretreated corn stover.

Enzymatic conversion of oligomeric xylose and insoluble xylan remaining after effective pretreatment offers significant potential to improve xylan-to-xylose yields while minimizing yields of degredation products and fermentation inhibitors. In this work, a commercial enzyme cocktail is demonstrated to convert up to 70 % of xylo-oligomers found in dilute acid-pretreated hydrolyzate liquor at varying levels of dilution when supplemented with accessory enzymes targeting common side chains. Commercial enzyme cocktails are also shown to convert roughly 80 % of insoluble xylan remaining after effective high-solids, dilute acid pretreatment.

Process and technoeconomic analysis of leading pretreatment technologies for lignocellulosic ethanol production using switchgrass.

Six biomass pretreatment processes to convert switchgrass to fermentable sugars and ultimately to cellulosic ethanol are compared on a consistent basis in this technoeconomic analysis. The six pretreatment processes are ammonia fiber expansion (AFEX), dilute acid (DA), lime, liquid hot water (LHW), soaking in aqueous ammonia (SAA), and sulfur dioxide-impregnated steam explosion (SO(2)). Each pretreatment process is modeled in the framework of an existing biochemical design model so that systematic variations of process-related changes are consistently captured.