The final report of Subcontractor to P4:

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The final report of Subcontractor to P4 Pulp
and Paper Research Institute
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1. Experiments in case laboratory conditions
Regime parameters of delignification
Preparation of cellulose It was used sulfate
unbleached softwood cellulose from Marijskij Pulp
and paper mill (Volgsk, Russia). The cellulose
was soaked with distilled water, disintegrated
and beaten in labor Hollander at low loading.
After beating cellulose had a beating 20 gad. SR.
The prepared pulp was divided for two parts. One
was used for paper sheet preparation and
brightness of them to estimate (Leicometer
Zeiss). The other one was washed in distilled
water till pH about 7, dried at 20 ?C to constant
weight and Kappa number was tested according
TAPPI method T 236 CM 85. Paper sheets of 60 g/m2
were prepared on Rapid-Ketten apparatus. The
preparations of blue laccase from Coriolus
hirsutus and new oxidoreductase from Coriolus
pubescence were delivered by Biochemistry
Institute. The specific laccase activity measured
toward catechol was not less than 350 units/mg of
protein for Coriolus hirsutus (the enzyme
concentration is about 15 mg/ml) and 230 units/mg
of protein for Coriolus pubescence (the enzyme
concentration is about 1 mg/ml). Delignification
assay In 3-throats retort equipped with
refrigerator and put in termostable condition the
prepared sample cellulose (2 g), buffer solution
and water were loaded. Then air bubbling was
begun (8 l/min). After period of time when
getting demanding temperature the portion of
laccase together with HBT (before mixed) was
added in retort. After incubation the pulp was
washed on Buchner funnel with water but then the
lignin extraction was made, using 5 NaOH at 60
?C during 1 hour. Then pulp was washed till pH
about 7, dried at 105 ?C and Kappa number was
tested. Besides the paper sheet was prepared and
brightness was estimated too. The regime
parameters are in the tables.
Kappa number and pulp brightness as a function of
time and temperature of incubation
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2. Experiments in pilot installation
The concentration of HBT was always 0.005 mol/l.
The dosage of T.hirsuta laccase liquide was
100ml/4 l pulp suspension
The process of enzyme treatment included next
operations - the kraft hard wood unbleached
cellulose (100 g) was fragmentated by hans for
pieces about 1x1 cm, - fragmentated cellulose was
diasintergated in 4 L of SW in disintegrator 1
hour, SW was before heated till 50oC, -
disintegrated pulp of about 2.5 concentration
was loaded into RD, but RD was put in SD and
stirrer was on, and pH about 5.0 was established
with sulphuric acid. - thermostate was on and it
waas necessary to wait for some time till getting
necessary temperature, and getting stable pH, -
the necessary qualittty of blue enzyme was added
togetheer with HBT (Water solution soome
cristalls citric acid) into pulp in RD, - air
minipulp was on. Than pulp treatment took 3-6
hours, and pulp was filtered till about 10 and
was leached with 5 NaOH 1 hours, the pulp
suspension again filtered and washed with SW till
pH 7-8. Washed and dried pulp was tested for
Kappa number. Additionally th paper sheets were
prepared to control of brightness.
The scheme of the pilot plant for delignification
of cellulose using laccase-mediator
system (incubation drum(1), drum for support
stable temperature (2), air peristaltic pump (3),
stirrer 300 rev. per minute (4))
installation.
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Kappa number and cellulose brightness of enzymed
and NaOH leached pulp prerared on pilot
installation.
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Conclusions
1. The principal possibility of pulp bleaching
using LMS in cases laboratory conditions and
pilot installation was shown.
2. It was discovered that the cultural liquid of
T. hirsuta is more effective for bleaching
process to compare with T. pubescence.
3. The pilot plant for delignification of
cellulose using laccase-mediator system was
designed.
4. It was shown that the results which were
received in the laboratory conditions were
similar to the results in case of the pilot
installation, though the data of pilot
investigation were a little worse.
5. The low efficiency of delignification to
compare to process expenses has been shown.
Further investigation in this direction are
necessary, and they have to be focused on
searching of laccases and redox mediators with a
pH-optimum close to alkali condition. It would be
closer to real practice because the cellulose has
normally pH about 9.0 after washing.