The transformation of wine yeasts with glucanase, xylanase and pectinase genes for improved clarification and filterability of wine


Project Number
IWBT 01-03

Project title
The transformation of wine yeasts with glucanase, xylanase and pectinase genes for improved clarification and filterability of wine

Project leader
Van Rensburg, P

Institution
University of Stellenbosch. Faculty of AgriSciences. Institute for Wine Biotechnology

Team members
Van der Merwe, T
Strauss, M L A

Project description
The development of recombinant wine yeast strains that can degrade polysaccharides such as glucan, pectin and xylan. Polysaccharide-degrading wine yeast strains could facilitate clarification of must and wine during fermentation without adding expensive commercial enzyme preparations.

In wine, the presence of alcohol intensifies the viscosity and clogging problems due to the presence of colloids. These colloids consist of polysaccharides (glucan, pectin and xylan), proteins and polyphenols. Polysaccharides are mainly grape pectins and neutral polysaccharides, ß-glucans originating either from yeast or Botrytis cinerea in the case of infected grapes. Some bacteria may also release polysaccharides in wine. These molecules can be classified as (i) linear polysaccharides, causing clarification and filtration problems and (ii) globular polysaccharides, such as the mannoproteins, stabilising aroma compounds as well as the colloidal system of wines. Wine made from botrytised grapes often present serious clarification and filtration problems. Difficulties arise because of the presence of a high molecular weight polysaccharide,b-1,3-1,6-glucan, secreted by the grey mould Botrytis cinerea. This glucose polymer is released into the grape juice and later found in the wine. Glucan prevents the natural sedimentation of cloud particles in the grape must and causes filter stoppages. This negative effect can be partly overcome by using fining agents such as bentonite, or by centrifugation. Such treatment will force the sedimentation of the cloud but will not remove the glucan and therefore the filtration problem remains. Alcohol induces polymerisation of the glucan molecules, thus more severe problems occur at the end of alcohol fermentation. Wine yeasts, transformed with heterologous glucanase, pectinase and xylanase genes, would secrete these polysaccharide-degrading enzymes during fermentation into the grape must and may therefore have applications in grape juice clarification, colour and flavour enhancement.

Presentation(s)

Van Rensburg, P. 1997. Co-expression of heterologous genes encoding endo-ß glucanase, cellobiohydrolase, cellodextrinase and cellobiase in Saccharomyces Cerevisiae. Paper presented at the18th International Congress on Yeast Genetics and Molecular Biology. Stellenbosch, South Africa.

Van Zyl, W H, La Grange, D C, Van Rensburg, P, Petersen, S H, Pieterse A and Pretorius, I S. 1998. Expression and production of hydrolase in yeast. Paper presented at the 10th Congress of the South African Society for Microbiology. Durban, South Africa.

Van Rensburg, P, Strauss, M L A, Lambrechts, M G, Jolly, N P and Pretorius, I S. 1999. Screening of non-Saccharomyces wine yeast for the presence of extracellular hydrolytic enzymes. Paper presented at the 23rd National Congress of the South African Society for Enology and Viticulture. 12-13 November, Cape Town, South Africa.

Van Zyl, W H, La Grange, D C, Van Rensburg, P, Petersen, S H, Crous, J M, Luttig, M and Pretorius, I S. 1999. Heterologous production of lignocellulosic hydrolases in Saccharomyces cerevisiae. Paper presented at the IEA Bioenergy Workshop: Biotechnology for the Conversion of lignocellulose, South Africa.

Fundira, M, Blom, M, Pretorius, I S and Van Rensburg, P. 2000. Optimisation of fermentation processes for the production of indigenous fruit wines. Paper presented at the 2nd International Congress of the South African Society for Enology and Viticulture. 8-10 November, Cape Town, South Africa.

Van Rensburg, P and Pretorius, I S. 2000. Development and evaluation of polysaccharide-degrading strains of Saccharomyces cerevisiae. VH Yeast Conference. Berlin, Germany.

Van Zyl, W H, La Grange, D C, Van Rensburg, P, Petersen, S H, Crous, J M, Luttig, M and Pretorius, I S. 1999. Heterologous production of lignocellulosic hydrolases in
Saccharomyces cerevisiae. Presentation at the IEA Bioenergy Workshop: Biotechnology for the Conversion of Lignocellulose, Itala Game Reserve, Kwazulu-Natal, South Africa.

Van Zyl, W H, La Grange, D C, Van Rensburg, P, Petersen, S H, Setati, M E, Den Haan, R and Pretorius, I S. 2000. Heterologous production of lignocellulosic hydrolases in yeast and filamentous fungi. Paper presented at the 10th International Symposium on Yeast. Papendal, The Netherlands.

Van Zyl, W H, La Grange, D C, Van Rensburg, P, Petersen, S H, Setati,M E, Den Haan, R and Pretorius, I S. 2000. Genetic engineering of yeast to produce lignocellulosic hydrolases. Paper presented at the 10th International Symposium on Yeast. Papendal, The Netherlands.

Fundira, M, Blom, M, Pretorius, I S and Van Rensburg, P. 2000. Optimisation of
fermentation processes for the production of indigenous fruit wines. Paper presented at the 2nd International Congress of the South Africa for Enology and Enology. 8-10 November, Cape Town, South Africa.

Van Rensburg, P and Pretorius, I S. 2000. Development and evaluation of
polysaccharide-degrading strains of Saccharomyces cerevisiae. VH-Yeast Conference. Berlin, Germany.

Van Rensburg, P, La Grange, D C, Pretorius, I S, Van Zyl, W H, Fan, A, Friedlander, L and Lynd, I R. 2001. Development and characterization of recombinant Saccharomyces strains expressing saccharolytic enzymes. Paper presented at the 23rd Symposium on Biotechnology for Fuels and Chemicals. Colorado, United States.

Van Zyl, W H, La Grange, D C, Van Rensburg, P, Rose, S H, Setati, M E, Den Haan, R, Pretorius, I S, Fan, Z, Zhang, Y and Lynd, L R. 2001. Heterologous production of lignocellulosic hydrolases in yeast and filamentous fungi. Cellulases and Cellulosomes. Presentation at the Procter Academy, NH, United States.

Van Rensburg, P, Strauss, M L A, Lambrechts, M G and Pretorius, I S. 2001. A novel approach to improve the colour of Pinot noir wines. Paper presented at the 25th National Congress of the South African Society for Enology and Viticulture. 15-16 November, Somerset West, South Africa.

Van Rensburg, P. 2001. Enzymes in winemaking: harnessing natural catalysts for efficient biotransformations. Presentation to the Universidad de Castilla – La Mancha, Ciudad Real, Spain.

Article
Petersen, S H, Van Zyl, W H, Pretorius, I S. 1998. Development of a polysaccharide-degrading strain of Saccharomyces cerevisiae, Biotechnology Letters, v. 12 (p. 615-619)

Van Rensburg, P, Pretorius, I S. 1998. Ensieme betrokke by wynproduksie. Deel I, Wynboer, Mnth Dec (p. T5-7)

Van Rensburg, P, Van Zyl, W H, Pretorius, I S. 1998. Engineering yeast for efficient cellulose degradation, Yeast, v. 14 (1) (p. 67-76)

Van Rensburg, P. 1999. Ensieme betrokke by wynproduksie. Deel III, Wynboer, Mnth Feb (p. T10-12)

Van Rensburg, P. 1999. Ensieme betrokke by wynproduksie. Deel II, Wynboer, Mnth Jan (p. T8-10)

Van Rensburg, P, Pretorius, I S. 2000. Enzymes in winemaking: Harnessing natural catalysts for efficient biotransformations – a review, South African Journal of Enology and Viticulture, v. 21 Special issue (p. 52-73)

Strauss, M L A, Jolly, N P, Lambrechts, M G, Van Rensburg, P. 2001. Screening for the production of extracellular hydrolytic enzymes by non-Saccharomyces wine yeast, Journal of Applied Microbiology, v. 91 (1) (p. 182-190)

Fundira, M, Bloom, M, Pretorius, I S, Van Rensburg, P. 2002. Comparison of commercial enzymes for the processing of marula pulp, wine and spirits, Journal of Food Science, v. 67 (6) (p. 2346-2351)

Van Rensburg, P, Pretorius, I S. 2006. Development and evaluation of polysaccharide-degrading strains of Saccharomyces cerevisiae, Journal of Biotechnology
Journal of Biotechnology, v. 125 (4) (p. 447-461)

FinalReport.pdf

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