Non-chlorine bleaching of kraft pulp

Details Non-chlorine bleaching of kraft pulp Non-chlorine bleaching of kraft pulp

1994-06-23

1997-11-25

Czaja, Donald E.

Chemistry: molecular biology and microbiology

Process of utilizing an enzyme or micro-organism to destroy...

Treating animal or plant material or micro-organism

435277, 435911, 162 1, 162 9, 162 70, 162 71, D21C 300

Patent

active

056911939

ABSTRACT:
A process for the bleaching of kraft pulps with non-chlorine chemicals, employing a sequential reaction of oxidative enzymes and hydrogen peroxide. The kraft pulp can be from conventional or extended pulping, or from an oxygen delignification step. The enzyme reaction is monitored by methanol release which results from the demethylation of lignin. The process essentially comprises three steps. The first step is the oxidation of kraft pulp either with manganese peroxidase enzyme in the presence of Mn(II) salts, hydrogen peroxide and chelator, or with laccase enzyme preferably in the presence of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), or a combination of both enzymes in a crude mixture as typically produced by certain fungi. The Mn(II) salts and chelator may already be present in sufficient amount in the pulp. This first step is performed at an acidic pH, and moderate temperatures for a period of time between 30 and 240 minutes. The two subsequent steps are the chelation of metals in the pulp and the alkaline hydrogen peroxide treatment.

REFERENCES:
patent: 4690895 (1987-09-01), Farrell
patent: 4830708 (1989-05-01), Paice et al.
Call et al., "Application of Lignolytic Enzymes in the Production of Pulp and Paper". Das Papier 44 Oct. (1990) pp. 32-41.
Lierop et al. "Using Oxygen and Peroxide to Bleach Kraft Pulps" 79th Annual Meeting, Technical Section, CPPA (1992) B81-B99.
Paice et al., Appl. Environment. Microbiol., 59:260-265 (1993).
Vikari et al. "Bleaching with Enzymes" Stockholm, Sweden Jun. 16-19, 1986 Biotechnology in the Pulp & Paper Industry, 3rd Int. Conf. pp. 67-69.
Bourbonnais & Paice "Demethylation & Delignification of Kraft Pulp by Trametes versicolor laccase in the Presence of 2,2-azinobis-(3-ethylbenzthiazoline-6-sulphonate") Appl. Microbiol. Biotechnol. 36:823-827 (1992).
Hammel et al. "Depolymerization of a Synthetic Lignin in vitro by lignin peroxidase" Enzyme Microbial. Technol. 13:15-18 (1991).
Wariishi et al. "In vitro depolymerization of Lignin by Manganese Peroxidase of Phanerochaete chrysosporium" Biochem. Biophys. Res. Commun. 176:269-275 Apr. 15, 1991.
Arbeloa et al. "An Evaluation of the Potential of Lignin Peroxidases to Improve Pulps" Tappi J. 75(3):215-221 (1992).
Reid & Paice "Biological Bleaching of kraft Pulp: A Review" in Frontiers in Industrial Mycology /G.F. Leatham, ed.) pp. 112-116 (1992).

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