Pretreatment and enzymatic process modification strategies to improve efficiency of sugar production from sugarcane bagasse
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Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
3 Biotech
Abstract
Pretreatment and enzymatic hydrolysis play a
critical role in the economic production of sugars and fuels
from lignocellulosic biomass. In this study, we evaluated
diverse pilot-scale pretreatments and different post-pretreatment
strategies for the production of fermentable sugars
from sugarcane bagasse. For the pretreatment of
bagasse at pilot-scale level, steam explosion without catalyst
and combination of sulfuric and oxalic acids at low and
high loadings were used. Subsequently, to enhance the
efficiency of enzymatic hydrolysis of the pretreated
bagasse, three different post-pretreatment process schemes
were investigated. In the first scheme (Scheme 1), enzymatic
hydrolysis was conducted on the whole pretreated
slurry, without treatments such as washing or solid–liquid
separation. In the second scheme (Scheme 2), the pretreated
slurry was first pressure filtered to yield a solid and
liquid phase. Following filtration, the separated liquid
phase was remixed with the solid wet cake to generate
slurry, which was then subsequently used for enzymatic
hydrolysis. In the third scheme (Scheme 3), the pretreated
slurry was washed with more water and filtered to obtain a
solid and liquid phase, in which only the former was subjected
to enzymatic hydrolysis. A 10 % higher enzymatic
conversion was obtained in Scheme 2 than Scheme 1,
while Scheme 3 resulted in only a 5–7 % increase due to
additional washing unit operation and solid–liquid separation.
Dynamic light scattering experiments conducted on
post-pretreated bagasse indicate decrease of particle size
due to solid–liquid separation involving pressure filtration
provided increased the yield of C6 sugars. It is anticipated
that different process modification methods used in this
study before the enzymatic hydrolysis step can make the
overall cellulosic ethanol process effective and possibly
cost effective.
Description
Keywords
Pilot-scale pretreatment Dilute acid treatment High-solid enzymatic hydrolysis Pressure filtration Solid–liquid separation