Chemistry: molecular biology and microbiology – Treatment of micro-organisms or enzymes with electrical or... – Modification of viruses
Patent
1986-01-30
1990-01-16
Huleatt, Jayme A.
Chemistry: molecular biology and microbiology
Treatment of micro-organisms or enzymes with electrical or...
Modification of viruses
435209, 435255, 435320, 935 14, 935 28, 935 69, 935 48, 536 27, C12N 1500, C12N 942, C12N 116, C07H 2100
Patent
active
048943380
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
Three different classes of enzymatic activity have been shown to be required for the complete hydrolysis of cellulose to glucose. The two major activities involved in cellulose solubilization are endoglucanase (EC 3.2.1.4) and cellobiohydrolase (EC 3.2.1.91) (1, 2). For the production of glucose a third type of activity, cellobiase or .beta.-glucosidase (EC 3.2.1.21) is also required. The precise manner in which these three different classes of enzyme interact to bring about the complete hydrolysis of cellulose is not yet clear.
Same filamentous fungi produce a number of different isoenzymes of each class of cellulolytic enzyme which apparently interact synergistically in hydrolysis (3, 4, 5, 6).
Trichoderma has been shown to produce at least two immunologically distinct cellobiohydrolases CBH I and CBH II, at least 2 endoglucanases, ENDO II and ENDO III, and a .beta.-glucosidase. While enzymatic hydrolysis of cellulose proceeds most rapidly in the presence of all these enzymes, CBH I alone is able to degrade crystalline cellulose to glucose and cellobiose (7, 8, 9).
Two groups have reported the molecular cloning of the T. reesei gene for CBH I and the complete sequence of this gene is known (10, 11).
Yeast is an important industrial organism and is used for brewing, wine making, baking, ethanol production, single cell protein production and more recently for the production of pharmaceuticals such as interferon, growth hormone and Hepatitis B virus antigen. Yeast do not produce enzymes that degrade cellulose. The development of yeast strains able to hydrolyse cellulose would make possible improvements in existing processes where cellulose or glucans are present in the raw material used. As important would be the possibility of developing new processes not currently possible.
In filtration and clarification of beer high molecular weight .beta.-glucans originating from barley grain cause problems. In the brewing industry microbial .beta.-glucanases are used to remove these .beta.-glucans. If the yeast used in the production of beer were able to produce endoglucanases, the filterability of beer would significantly be improved and the cost of filtering would decrease. By transferring individual fungal cellulase genes to yeast it is possible to produce yeast strains that produce only one cellulase enzyme. Such yeast strains would produce enzymes for use in, for example the pulp and paper industry. Cellulose used in paper making could be swelled by pretreating with one cellulase enzyme, which would bring about swelling without excessive hydrolysis of cellulose.
There are two ways in which a foreign gene can be expressed in yeast. The simplest is to join the whole gene from the chromosome of the donor organism to a yeast vector and transform a yeast cell. If the yeast genetic system recognizes the appropriate sequences in the transferred gene the gene will be expressed. However, in practice this is rare and depends at least in part on the genetic distance between the donor organism and the yeast.
For example, of the five genes from Aspergillus niger tested in Saccharomyces cerevisiae, only one of these was found to express (12). Therefore it cannot be assumed that heterologous genes will automatically be expressed in yeast.
The second method of obtaining expression of genes in yeast is by connecting either the chromosomal gene or a cDNA copy of the messenger RNA coding for the desired gene to a yeast promotor sequence. In this way, human eukaryote interferon (13), hepatitis B virus surface antigen (14), bovine rennin (15), and mouse .alpha.-amylase (16) have all been expressed in yeast.
These and other studies show that while expression of the cDNA or gene is always obtained, the amount and cellular location of the product is very difficult to predict in the absence of experimentation. Montenecourt (1) outlined a number of possible cloning strategies for cloning cellulase genes from T. reesei but did not describe the methods to be used to achieve the goal.
SUMMARY OF THE INVENTION
REFERENCES:
patent: 4394443 (1983-07-01), Weissman etal.
patent: 4615974 (1986-10-01), Kingsman et al.
Fagerstam et al., Febs Letters, vol. 119, pp. 97-100, 1980.
Pettersson et al, Ekman-Days, Int. Symp. Wood Pulping Chemistry, vol. 3, pp. 39-42, 1981.
Teeri, T. et al, Gene, vol. 51, pp. 45-52, 1987.
Henrissat et al, Bio/Technology, vol. 3, pp. 722-726, Aug. 1985.
Chen, C. et al, Bio/Technology, vol. 5, pp. 274-278, Mar. 1987.
van Tilbeurgh et al., Fed. Eur. Biochem. Societies 169(2): 215-218 (1984).
Gong et al., Adv. Chem. Ser. 181:261-287 (1979).
Teeri et al., Bio/Technology, pp. 696-699, (Oct. 1983).
Shoemaker, Schwieckart et al., Bio/Technology, pp. 691-695 (Oct. 1983).
Shoemaker, Watt et al., Bio/Technology, pp. 687-690, (Oct. 1983).
Mellor et al., Gene 24:1-14 (1983).
James et al., Proc. Bioenergy R & D Semin. 3d: 135-139 (1981).
Seligy, V. et al, Gene Expression in Yeast. Proceedings of the Alko Yeast Symposium, Helsinki, 1983, (ed. by M. Korholac E. Vaisanen), pp. 167-185.
Knowles Jonathan
Lehtovaara-Helenius Paivi
Nevalainen Helena
Penttila Merja
Salovuori Irma
Huleatt Jayme A.
Oy Alko AB
LandOfFree
Yeast strains producing cellulolytic enzymes and methods and mea does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Yeast strains producing cellulolytic enzymes and methods and mea, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Yeast strains producing cellulolytic enzymes and methods and mea will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1334696