Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing compound containing saccharide radical
Patent
1996-11-13
1997-11-18
Wax, Robert A.
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing compound containing saccharide radical
C12P 1944, C12N 924, C12N 942
Patent
active
056886683
DESCRIPTION:
BRIEF SUMMARY
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a 35 U.S.C. 371 national application of PCT/DK95/00211 filed 31 May 1995, which is incorporated herein by reference.
FIELD OF INVENTION
The present invention relates to a novel thermostable amylase and to a novel thermostable pullulanase and their use in the production of sweeteners and ethanol from starch, and to a novel thermostable xylanase and its use in the paper and pulp industry.
BACKGROUND OF THE INVENTION
The production of sweeteners from starch has been largely improved by application of different microbial enzymes to obtain better quality and yields, but the necessity of performing several steps of the starch-hydrolysing process at elevated temperatures means that there is still a need for new starch-hydrolysing enzymes with increased thermal stability.
It is known that Pyrococcus, e.g. Pyrococcus woesei and Pyrococcus furiosus, for reference see Arch. Microbiol. 155, 1991, pp. 572-578, and Appl. Env. Microbiol. 56, 1990, pp.1985-1991, can produce highly thermostable amylases.
The paper and pulp industry is using xylanase compositions in the bleaching process to enhance the brightness of bleached pulps, to decrease the amount of bleaching chemicals, e.g. chlorine, used in the bleaching stages, and to increase the freeness of pulps in the recycled paper process.
Thermostable xylanases from Thermotoga have been described, for reference see Biochem. J. 277(2), 1991, pp. 413-418.
It is the object of this invention to provide a xylanase, an amylase and a pullulanase with temperature optimum at 100.degree. C. or above 100.degree. C.
SUMMARY OF THE INVENTION
We have unexpectedly found that a novel thermostable xylanase, a novel thermostable amylase and a novel thermostable pullulanase can be obtained from the genus Pyrodictium, a genus not previously reported to produce thermostable xylanases, amylases and pullulanases; these new enzymes have temperature optimum around 110.degree.-120.degree. C.
Accordingly, the invention provides a xylanase preparation, characterized by being producible by cultivation of a xylanase producing strain of the genus Pyrodictium, and an amylase preparation, characterized by being producible by cultivation of an amylase producing strain of the genus Pyrodictium, and a pullulanase preparation, characterized by being producible by cultivation of a pullulanase producing strain of the genus Pyrodictium.
BRIEF DESCRIPTION OF DRAWINGS
The present invention is further illustrated by reference to the accompanying drawings, in which:
FIG. 1 shows the relative activity (% rel.) of an amylase (.diamond-solid.) and a pullulanase (.quadrature.) of the invention at various temperatures (determined at pH 5.5 with starch and pullulan, respectively, as substrate).
FIG. 2 shows the relative activity (% rel.) of a xylanase of the invention at various temperatures (determined at pH 5.5 with xylan as substrate), and FIG. 3 shows the relative activity of a xylanase of the invention at various pH (determined at 100.degree. C. with xylan as substrate).
DETAILED DISCLOSURE OF THE INVENTION
The Microorganism
Looking for extremely thermostable enzymes the extremely thermophilic archaebacteria may be a possible source. Very stable extracellular enzymes from archaebacteria have also been reported, for reference see J. M. Bragger et al. "Very stable enzymes from extremely thermophilic archaebacteria and eubacteria" in Appl. Microbiol. Biotechnol. 31, 1989, p. 556-561. The genus Pyrodictium, however, has not been reported before to produce extracellular amylases, pullulanases and xylanases, in fact it is the first time a member of the family Desulfurococcaceae has been reported to produce an extracellular xylanase. A survey of the taxonomy of the family Desulfurococcaceae is described in "The Prokaryotes; A Handbook on the Biology of Bacteria: Ecophysiology, Isolation, Identification, Applications", 2 nd Ed., Springer-Verlag, Vol I, p. 678.
According to the invention, xylanase is derived from a xylanase producing strain of the
REFERENCES:
patent: 4966850 (1990-10-01), Yu et al.
patent: 5491086 (1996-02-01), Gelfand et al.
Koch et al., "Purification And Properties Of A Hyperthermoactive .alpha.-Amylase From The Archaeobaterium Pyrococcus Woesei", Arch Microbiol (1991) 155: pp. 572-578.
Yoshioka et al., "Production and Characterization Of Thermostable Xylanase From Talaromyces Byssochlamydoides", Agric. Biol. Chem. 45(30), 1981 pp. 579-586.
Brown et al., "Characterization of Amylolytic Enzyme Activities Associated With Hyperthermophilic Archaebacterium Pyrococcus Furiosus", Applied And Environmental Microbiology, Jul. 1990, vol. 56, No. 7, pp. 1985-1991.
Antranikian Garabed
Sj.o slashed.holm Carsten
Gregg, Esq. Valeta
Novo Nordisk A S
Slobodyansky Elizabeth
Wax Robert A.
Zelson Esq. Steve T.
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