Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving oxidoreductase
Patent
1999-08-19
2000-09-26
Leary, Louise N.
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving oxidoreductase
435 4, 4352831, 435 28, 536 56, 422 50, 422 681, C12Q 130, C12Q 100, C12Q 128
Patent
active
061241113
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method and a device for measuring the quantity/activity of the enzyme catalase before or during bleaching preferably of cellulose fibres in a pulp suspension in providing a better and more uniform product quality and a correct dosing of the bleaching chemical used.
In the pulp and paper industry the bleaching of cellulose fibres is essential to the final product quality. Principally, the bleaching has two aims, namely first to create a continuation of the lignin-separating process, which consists of cooking in the manufacture of chemical pulps, and second to remove the dark colour given to the pulp by certain organic substances so that a certain brightness is created. Previously a method is known for measuring of the content of chemicals during bleaching of cellulose fibres in forest industry processes. Said method is based on that the enzyme catalase is added to the measurement sample, whereby said bleaching chemical is decompositioned and a gas is formed. The quantity of gas is then a measure on how much of said bleaching chemical existing in the sample. The gas quantity is measured by a special device based on a manometric method. The method has shown to function excellent for e.g. peroxide, which today is a very common bleaching chemical in connection with the forest industry. Here, it is important to measure the content of peroxide which remains after the bleaching process, i.e. the content of residual peroxide. This has a great importance for the fibre quality achieved.
In the pulp processes where microbiological activity exists principally during the production of recycle fibres, the enzyme catalase is produced from certain microorganisms.
Exactly as in the method described above then the peroxide is decomposited into water and oxygen gas, the amount of peroxide in the fibre suspension being decreased. This is a process technical worry. An indication of the content/activity of catalase shoud open possibilities to act.
The object of the present invention is to provide method and a device of the type mentioned above, by means of which method and device the disadvantages above referred to are eliminated. The features characterizing the invention appear from the subsequent patent claims.
Thanks to the invention there do now exist a method and a device yielding a quick result, whereby an indication is obtained about how large content/activity of catalase a fibre suspension contains before or in connection with the bleaching, so that a compensation can be made for that during the calculation or measuring of the content of chemicals-residual peroxide during the bleaching in achieving of a final result as correct as possible.
An embodiment exemplifying the intention of the invention will now be described in greater detail, reference being made to the accompanying drawing, which is a diagrammatic view of a measurement device according to the present invention.
The method according to the invention is based on the fact that the instability of the bleaching chemical to easily decompose is taken care of, whereby oxygen gas is formed if the enzyme catalase exists. By adding a certain amount of bleaching substance, preferably peroxide, to a sample having a predetermined volume taken from the pulp suspension, before or during the bleaching of cellulose fibres in a pulp suspension, now a measure/activity of catalase exsisting in the suspension instead of residual peroxide can be achieved.
The filtrate from the fibre suspension, which can contain catalase, is added to the measurement container of the measuring device. In stead of dosing of catalase into the sample, as during determining of peroxide, now a predetermined amount of peroxide is dosed. Hereafter principally the normal measurement sequence follows with stirring and measuring. Presence of catalase in the measurement sample gives a decomposition of the peroxide dosed and the gas amount formed hereby is a measure on the content/activity of catalase. A certain fault-measuring could happen if the sample is not only containing
Fladda Gerdt
Norder Stig
Olsson Bertil
BTG Kalle Inventing AB, A Corp.
Leary Louise N.
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