Development Of Solid State Fermentation System For Enzyme Production And Its Usage In A Pilot Scale Deinking Of Printed Waste Paper
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Date
2010-12
Authors
Lee, Chee Keong
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Abstract
The present work deals with the development of solid state fermenter for enzymes
production and the development of a pilot scale of enzymatic deinking system. The
newly developed solid state fermenter, was named FERMSOSTAT®, which was
used for the production of cellulases and xylanase using a local isolate; Aspergillus
niger USM AI 1. Optimization of enzymes production was carried out and the
optimum conditions obtained were 0.5 kg substrate (a combination of PKC and
sugarcane baggase at 1:1 ratio); 70% (w/w) moisture content; incubated at 30°C;
aeration at 4.0 L/heg fermented substrate for 5 min and mixing at 0.5 rpm for 5 min.
Under the optimum SSF conditions, the CMCase, xylanase and FPase activities
obtained were 62.6 U/g, 390.8 U/g and 3.4 U/g, respectively. This represents about
9.6, 7.8 and 3.4 folds increased in their respective enzymes activities after the
optimization process. When comparative study on the enzymes production was
performed using Trichoderma reesei, the CMCase, xylanase and FPase activities
obtained were about 57.3 U/g, 563.0 U/g and 2.2 U/g, respectively. The enzymes
produced were used in the deinking studies of mixed office waste paper (MOW) and
old newspaper (ONP) using newly developed pilot scale enzymatic deinking system.
Optimization of enzymatic deinking process was carried out and the optimum
conditions obtained for MOW were pulping at 2% consistency for 60 min; enzymatic
hydrolysis at 50°C, pH 5.5, 0.8 U of CMCase and 4.0 U of xylanase per gram of air
dry weight of pulp and 60 min of hydrolysis time and flotation process at pH 8.0,
0.20% (w/w) of Tween 80 and 5 min of flotation time. Meanwhile, the optimum
conditions obtained for the de inking of ONP were pulping at 3% consistency for 45
min; enzymatic hydrolysis at 50°C, pH 5.5, 0.4 U ofCMCase and 2.0 U ofxylanase
per gram of air dry weight of pulp and 45 min of· hydrolysis time and flotation
process at pH 8.0, 0.55% (w/w) of Tween 80 and 20 min of flotation time. The
deinking efficiency obtained for MOW and ONP under their respective optimum
conditions were about 6.0% and 6.3%, respectively. The deinking efficiency detected
by chemical deinking of MOW and ONP were about 2.9% and 3.5%, respectively.
Both enzymatic and chemical deinking processes not only significantly influence
optical and mechanical properties of the deinked paper but also the pulp properties
and the effluent generated. Enzymatic deinking of MOW showed improvement in
brightness (4.7 units), tensile index (14.1%), burst index (3.4%), freeness (2.0%) and
residual ink removal (44.5%) but decreased in opacity (2.6%) and tear index (9.6%).
Meanwhile, enzymatic deinlcing of ONP showed improvement in brightness (2.5
units), tensile index (10.2%), burst index (3.8%), freeness (2.9%) and residual ink
removal (51.15%) but decreased in opacity (0.4%) and tear index (3.9%). Unlike
enzymatic deinking, chemical deinking of MOW demonstrated increased in the
brightness (2.3 units), tensile index (1.1 %), burst index (1.2%), freeness (1.9%) and
residual ink removal (31.1%) but loss in opacity (1.4%) and tear index (0.1%).
Meanwhile, chemical de inking of ONP showed enhanced in brightness (1.4 units),
tensile index (6.8%), burst index (3.0%), freeness (2.3%) and residual ink removal
(49.8%) but decreased in opacity (0.1%) and tear index (1.1%). Biological oxygen
demand (BODs) and chemical oxygen demand (COD) analysis indicated that,
effluent produced from the enzymatic deinking process was lower compared to
chemical deinking process. About 33.9% and 33.8% lower in COD values were
obtained after enzymatic deinking ofONP and MOW compared to chemical deinking
process, respectively. Meanwhile, BODs obtained from enzymatic deinking of MOW
and ONP were 47.1% and 39.3% lower compared to chemical deinking process,
respectively. This directly will reduce the wastewater treatment cost. In addition,
based on the Malaysia Environmental Act 1974; no wastewater treatment was
required on the effluent obtained from deinking of MOW, where the effluents
obtained were within the pennitted value for safety discharged into the environment.
The results obtained from this work suggested that the enzymatic deinking can be a
highly potential alternative to the chemical method, which showed several problems
and disadvantages compared to enzymatic deinking in the recycling of waste paper.
Description
Keywords
Solid State Fermentation System , Printed Waste Paper