A highly efficient dilute alkali deacetylation and mechanical (disc) refining process for the conversion of renewable biomass to lower cost sugars

Abstract

Background: The deconstruction of renewable biomass feedstocks into soluble sugars at low cost is a critical component of the biochemical conversion of biomass to fuels and chemicals. Providing low cost high concentration sugar syrups with low levels of chemicals and toxic inhibitors, at high process yields is essential for biochemical platform processes using pretreatment and enzymatic hydrolysis. In this work, we utilize a process consisting of deacetylation, followed by mechanical refining in a disc refiner (DDR) for the conversion of renewable biomass to low cost sugars at high yields and at high concentrations without a conventional chemical pretreatment step. The new process features a low temperature dilute alkaline deacetylation step followed by disc refining under modest levels of energy consumption.

Improving Sugar Yields and Reducing Enzyme Loadings in the Deacetylation and Mechanical Refining (DMR) Process through Multistage Disk and Szego Refining and Corresponding Techno-Economic Analysis

“…In a previous paper, single stage DRDCS at refining energies of ∼128 kWh/ODMT without a second stage Szego milling step showed glucose and xylose yields of ∼78% and ∼69%, respectively. 11 In this work, the addition of a second stage Szego milling step increased the monomeric glucose yields to approximately 90% and xylose yields to 84%, respectively. The over 10% higher sugar yields of the SM-DRDCS substrate compared to the DRDCS substrate shows that Szego milling could notably increase biomass digestibility even when the substrate was previously disk refined.…”

Use of mechanical refining to improve the production of low-cost sugars from lignocellulosic biomass

“…Recently, a pilot trial was performed with a 36-inch commercial scale disc refiner using alkali pretreated corn stover and the increased conversion was as shown in Figure 4 (Chen et al, 2014). The conversion was increased by 13% for glucose and 21% for xylose, respectively, with the refining energy input of 212 kWh/ODMT (oven dry metric ton).…”

“…It was observed that close to 20 percent points increase in both glucose and xylose conversion yield can be achieved with relatively low energy consumption by mechanical refining(Chen et al, 2014).…”

Enzyme biotechnology in degradation and modification of plant cell wall polymers

“…The modification and degradation of the cell wall components can also have adverse effects on the enzymes: the soluble degradation products (Rasmussen et al ) and modified lignin (Rahikainen et al , ) formed in the pretreatment can have an inhibitory effect on enzymatic hydrolysis. The combination of mild chemical deacetylation and mechanical refining has recently been reported to allow good enzymatic hydrolysis yields by efficiently increasing the accessible surface area for enzymes without the use of harsher chemistries (Chen et al ).…”