Question

Answer BOTH parts of this question:
a) There are many wine yeasts and each has its own strengths and weaknesses.
Briefly describe TWO (2) ways in which wine yeasts might be genetically modified, by whichever approach, to improve their performance in wine fermentations.

b) There are many approaches that can be used to improve the characteristics of a wine yeast. Discuss ONE (1) NON-genetic engineering approach that might be used to create a novel yeast strain and compare the advantages and disadvantages of this approach to genetic engineering approaches to the same problem.

Answer 1

1.We can reduce the alcohol content and produce a better wine with high quality and low ethanol.This can be done by partial deletion of the PDC2 gene of yeast. As current demand are softer wines with high tannins and polyphenols (Without genetic modification such conditions can be obtained along with the high ethanol content).

2.The genetic modification of the wine yeast with the genes encoding enzymes like glucanase, xylanase and pectinase for improved clarification and filterability of the wines.

b. The non genetic approach for producing a novel yeast strain is the process of recombination that occur during the sexual reproduction of the yeast. The reshuffling of the the genomes of different yeast strains can be done by mating yeast having different properties. Other than this we can mutate the yeast cell so that it can evolve in a new yeast strain with novel properties.

Advantages of genetic engineering process: There will be more successful chance of getting the recombinant gene by genetic modification like transforming the yeast with desired gene. It allow the user to insert the gene of own choice to get the desired results.

Disadvantage: Due to genetic modification there is possibility that it will express some deleterious byproducts that could be harmful for the user.