Chemistry: molecular biology and microbiology – Process of utilizing an enzyme or micro-organism to destroy... – Cleaning using a micro-organism or enzyme
Reexamination Certificate
1994-08-08
2001-07-17
Witz, Jean C. (Department: 1651)
Chemistry: molecular biology and microbiology
Process of utilizing an enzyme or micro-organism to destroy...
Cleaning using a micro-organism or enzyme
C424S094400, C435S262000, C435S267000, C435S266000
Reexamination Certificate
active
06261829
ABSTRACT:
The invention relates to a process of combatting micro-organisms in industrial processes, particularly in the processes of the wood processing industry. The invention is particularly suitable for the treatment of process waters and slurries in the wood processing industry, such as pulp and circulating waters, pigment slurries (kaolin, gypsum and talc slurries, etc.) and pulp and surface sizing slurries (starch slurries, etc.).
Industrial process waters and slurries often contain micro-organisms which may hamper the process and impair the quality of the product. For this reason, it is usually necessary to add chemical biocides to process waters and slurries, such as widespectrum bactericides and fungicides, see e.g. Finnish Patents 76 237 and 75 973 and U.S. Pat. Nos. 3,929,561 and 4,295,932. These biocides are highly poisonous (second-class poisons) and may degrade very slowly in the environment.
It has also been suggested to use enzymes which degrade micro-organisms, see e.g. Finnish Patent 75 973. Enzymes are not poisonous and do not pollute the environment; in addition, they are needed in very small quantities only (a few ppm). The suggested enzymes, however, are hydrolytic enzymes which are specific for certain polysaccharides only, in addition to which bacteria present in process waters usually adapt very rapidly to these enzymes. In other words, these enzymes have a low efficiency, and cannot be used in industrial processes.
In the paper industry in particular, it is absolutely necessary to combat micro-organisms. Pigment slurries and starch solutions often contain plenty of bacteria and fungi, and the process circulating waters contain plenty of nutrients. Furthermore, the temperature and pH are usually favourable, especially for the growth of fungi. Because of their thread-like growth, fungi may cause serious process disturbances, such as blocking of filters, occurrence of pinholes in paper, and colour defects.
Bacteria may cause formation of bad-smelling and even dangerous gases and corrosion of pipe systems and equipment. Only very low bacteria counts are acceptable in food-grade paper products, and the products must not contain any pathogenic bacteria.
By means of the process of the invention, it is possible to combat micro-organisms effectively and economically in industrial processes. The process of the invention uses glucose oxidase which is an oxidation-reduction enzyme (oxidoreductase). The enzyme binds oxygen and produces long-acting hydrogenperoxide which kills substantially all micro-organisms.
REFERENCES:
patent: 2482724 (1949-09-01), Baker
patent: 4414334 (1983-11-01), Hitzman
patent: 4478683 (1984-10-01), Orndorff
patent: 4996062 (1991-02-01), Lehtonen
patent: 1468405 (1977-03-01), None
Genencor International Inc.
Genencor International Inc.
Witz Jean C.
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