SciTech Connect

Title: Analysis of conversion of particulate biomass to ethanol in continuous solids retaining and cascade bioreactors

Analysis of conversion of particulate biomass to ethanol in continuous solids retaining and cascade bioreactors Design considerations for continuous conversion of biomass to ethanol using the simultaneous saccharification and fermentation (SSF) process are discussed. A previously presented and verified modeling approach is extended to describe advanced solid-substrate reactor systems incorporating solids and enzyme retention, and reaction in CSTR cascades. A single solids-retaining CSTR has predicted advantages over a batch process at low-residence time and conversion. The predicted performance of a cascade of CSTR reactors for SSF approaches that of the batch system, whereas a cascade system with differential retention of solids with respect to the aqueous phase (solids residence time = 1.5 times the liquid residence time) is predicted to allow a 47% decrease in overall reactor volume relative to a batch system at high conversion (90% cellulose utilization). Further benefits are anticipated because of the effects of substrate classification in nonwell-mixed reactor configurations. Apparatus for laboratory-scale experimentation using solid substrates is presented, along with progress toward experimental verification of the reactor concepts proposed. In addition to predicting bioreactor productivity, the modeling was used to examine ethanol tolerance. In contrast to the approximately linear inhibition trend observed for soluble substrates, the ratio of dilution rates necessary to achieve a fixed conversion in the absence and more » presence of inhibition is essentially unity until the maximum growth rate is approached, and falls precipitously thereafter. Implications of this and other simulation results for the bioreactor design are discussed. 32 refs., 5 figs., 1 tab. « less
Authors: ;
OSTI Identifier:6842471
Resource Type:Journal Article
Resource Relation:Journal Name: Applied Biochemistry and Biotechnology; (United States); Journal Volume: 45-46
Country of Publication:United States
Language:English
Subject: 09 BIOMASS FUELS; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; BIOMASS; BIOCONVERSION; BIOREACTORS; DESIGN; MATHEMATICAL MODELS; ETHANOL; BIOSYNTHESIS; ALCOHOLS; ENERGY SOURCES; HYDROXY COMPOUNDS; ORGANIC COMPOUNDS; RENEWABLE ENERGY SOURCES; SYNTHESIS 090900* -- Biomass Fuels-- Processing-- (1990-); 990200 -- Mathematics & Computers