Economic impact of total solids loading on enzymatic hydrolysis of dilute acid pretreated corn stover

Abstract

In process integration studies of the biomass-to-ethanol conversion process, it is necessary to understand how cellulose conversion yields vary as a function of solids and enzyme loading and other key operating variables. The impact of solids loading on enzymatic cellulose hydrolysis of dilute acid pretreated corn stover slurry was determined using an experimental response surface design methodology. From the experimental work, an empirical correlation was obtained that expresses monomeric glucose yield from enzymatic cellulose hydrolysis as a function of solids loading, enzyme loading, and temperature. This correlation was used in a technoeconomic model to study the impact of solids loading on ethanol production economics. The empirical correlation was used to provide a more realistic assessment of process cost by accounting for changes in cellulose conversion yields at different solids and enzyme loadings as well as enzyme cost. As long as enzymatic cellulose conversion drops off at higher total solids loading (due to end-product inhibition or other factors), there is an optimum value for the total solids loading that minimizes the ethanol production cost. The optimum total solids loading shifts to higher values as enzyme cost decreases.

Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Biological Conversion of Sugars to Hydrocarbons

“…The n th -plant assumptions in the present model apply primarily to the factored cost model used to determine the total capital investment from the purchased equipment cost and to the choices 8 made in plant financing. The n th -plant assumption also applies to some operating parameters, such as process uptime of 90%.…”

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

“…These process conditions are more favorable for the commercial production of biofuels, especially corn stover derived ethanol, because these conditions significantly reduce operational costs (enzyme and water usage) as well as capital costs due to the decreased size requirements for enzymatic hydrolysis reactors and downstream fermenters [40]. Therefore, following the previously discussed low solids enzymatic hydrolysis screening experiments, the DCS and DRDCS substrates were subjected to enzymatic hydrolysis at 15% (w/w) total solids using lower enzyme loadings (20 mg CTec3 (15 FPU) and 2.5 mg HTec3/g cellulose).…”

The exometabolome of Clostridium thermocellum reveals overflow metabolism at high cellulose loading

“…The beneficial effects of co-culturing were recently also demonstrated by Argyros et al, who showed that a co-culture of engineered strains of C. thermocellum and T. saccharolyticum was able to ferment 83 g/L of cellulose into an impressive 38 g/L ethanol (80% of the theoretical maximum), while a pure culture of the same C. thermocellum strain produced only 14 g/L of ethanol when cultured on 40 g/L cellulose [10]. Application in industrial processes is likely to require carbohydrate concentrations of 100 g/L carbohydrate or more [44], corresponding to lignocellulose loadings of at least 150 g/L on a dry matter basis.…”