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Modeling enzymatic hydrolysis of lignocellulosic substrates using confocal fluorescence microscopy I: Filter paper cellulose
Author(s) -
Luterbacher Jeremy S.,
MoranMirabal Jose M.,
Burkholder Eric W.,
Walker Larry P.
Publication year - 2015
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.25329
Subject(s) - hydrolysis , enzymatic hydrolysis , lignocellulosic biomass , cellulose , cellulosic ethanol , chemistry , biomass (ecology) , biological system , chemical engineering , chromatography , organic chemistry , biology , agronomy , engineering
Enzymatic hydrolysis is one of the critical steps in depolymerizing lignocellulosic biomass into fermentable sugars for further upgrading into fuels and/or chemicals. However, many studies still rely on empirical trends to optimize enzymatic reactions. An improved understanding of enzymatic hydrolysis could allow research efforts to follow a rational design guided by an appropriate theoretical framework. In this study, we present a method to image cellulosic substrates with complex three‐dimensional structure, such as filter paper, undergoing hydrolysis under conditions relevant to industrial saccharification processes (i.e., temperature of 50°C, using commercial cellulolytic cocktails). Fluorescence intensities resulting from confocal images were used to estimate parameters for a diffusion and reaction model. Furthermore, the observation of a relatively constant bound enzyme fluorescence signal throughout hydrolysis supported our modeling assumption regarding the structure of biomass during hydrolysis. The observed behavior suggests that pore evolution can be modeled as widening of infinitely long slits. The resulting model accurately predicts the concentrations of soluble carbohydrates obtained from independent saccharification experiments conducted in bulk, demonstrating its relevance to biomass conversion work. Biotechnol. Bioeng. 2015;112: 21–31. © 2014 Wiley Periodicals, Inc.