GERF Bulletin of Biosciences
December 2011, 2(2):29-31
Abstract
Introduction
*Corresponding author: dev.biochem@gmail.com
www.gerfbb.com
Short Communication
Copyright © 2011 Green Earth Research Foundation
Hydrolysis of wood saw dust by combined chemical pretreatment and
enzymatic methods for lignocellulosic saccharification
Devendra Kumar
1
*, Kaushlesh K. Yadav
2
and Munna Singh
1
1
Department of Botany, Lucknow University, Lucknow-226007, India
2
Department of Biotechnology, Dr. Ram Manohar Lohia Avadh University, Faizabad- 224001, India
Keyword: Wood saw dust (WSD), Aspergillus fumigatus, Acid hydrolysis, Enzymatic hydrolysis. Cellulose, Hemi-
cellulose.
Wood saw dust (WSD) after lignocellulosic saccharification by different hydrolysis methods is more efficient for ethanol
production as, its contains cellulose and hemi-cellulose at higher levels 65% (w/v) and 35% (w/v), respectively. Cellulose
and hemicellulose account for about a quarter of whole biomass in all land plants. A pretreatment method using chemical
hydrolysis and enzymatic conversion from starch into fermentable sugars was investigated. The WSD was hydrolyzed at
1.69 g/l, using a crude culture filtrate Aspergillus fumigatus at pH 5.0 and 30ºC in acetate buffer 50 mM, while 23.3 g/
l was with 1 N sulfuric acid (H
2
SO
4
) treatment. Aonla pomace waste was used as substitute to acid because of high acidic
nature. Optimum conditions for lignocellulosic saccharification is discussed in this paper.
High lignocellulosic agri-horticulture biomasses are
employed as alternative bio-energy (resource) to fossil
energy sources via lignocellulosic saccharification (Vintila
et al., 2010). Two processes used to convert cellulose and
hemicellulose into biofuel (ethanol) are enzymatic and acid
hydrolysis (Akin-Osanaiye et al., 2005; Chandel et al., 2007;
Jurcoane et al., 2009; Karmakar et al., 2011). The most
commonly adopted technique is acid hydrolysis (Badger et
al., 2002). Acidic hydrolysis is an effective method used for
lignocelluloses raw material pretreatment in saccharification
which could change into ethanol. Although acids are
powerful agents used for biomass hydrolysis, concentrated
acids are toxic, erosive and hazardous. Handling higher
concentrations of acid requires reactors that are resistant to
erosion in raw material pretreatment. Diluted acid hydrolysis
especially sulfuric acid has been successfully developed for
pretreatment of cellulosic materials.
Another method of hydrolysis is enzymatic hydrolysis.
Enzymes are naturally occurring plant proteins that result in
certain chemical reaction. However, for enzymes to work,
they must obtain access to the molecules to be hydrolyzed
(Baig et al., 2004). A combined strategy involving acid, base
and enzymatic methods in hydrolysis of saw dust is
investigated.
The WSD was collected in saw dust from Kakori industrial
area. The samples were brought to room temperature washed
with distilled water and used in the experiment.
Acid -base hydrolysis
The WSD 25% (w/v) was hydrolyzed with 100 ml (1:2 w/
v) of of various concentrations of H
2
SO
4
, HCl and NaOH at
room temperature treatment for 24 hr. The hydrolysates were
separated to obtain any suspended or unhydrolysated
materials and was neutralized by 2 N NaOH and 1 N H
2
SO
4
solution for analytical processing then autoclaved at 121ºC
and 15 lbs pressure for 15 min (Nat Steel Equipment Pvt. Ltd,
India).
Enzymatic hydrolysis
The WSD 25% (w/v) were hydrolyzed with various fungal
enzymes from (10
6
spores) of Aspergillus fumigatus,
Rhizopus, Trichoderma viridae and Aspergillus wenti) with
extra cellular enzymes ( i.e. α-amylase, glucoamylase,
cellulase and pectinase) were used in the experiment. The
hydrolyate was separated by centrifugation at 12,000 rpm at
room temperature.
Materials and Methods
Sample collection