Yeast expressing glucoamylase with enhanced starch hydrolysis

1. A recombinant yeast host cell for saccharification and fermentation of a biomass, the recombinant yeast host cell having a heterologous nucleic acid molecule encoding a heterologous polypeptide having glucoamylase activity, wherein the heterologous nucleic acid molecule comprises a first polynucleotide encoding the heterologous polypeptide having glucoamylase activity, wherein the polypeptide having glucoamylase activity has an amino acid sequence that is at least 95% identical to SEQ ID NO: 6; wherein the recombinant yeast host cell is from the genus Saccharomyces and capable of utilizing raw starch as a substrate.

2. The recombinant yeast host cell of claim 1 , further comprising a second polynucleotide encoding a signal sequence, wherein the second polynucleotide is operatively associated with the first polynucleotide.

3. The recombinant yeast host cell of claim 2 , wherein the signal sequence:

has an amino acid sequence that is at least 90% identical to SEQ ID NO: 21 having signal sequence activity;

has an amino acid sequence that is at least 90% identical to SEQ ID NO: 28 having signal sequence activity;

has an amino acid sequence that is at least 90% identical to SEQ ID NO: 25 having signal sequence activity;

has an amino acid sequence that is at least 90% identical to SEQ ID NO: 27 having signal sequence activity;

has an amino acid sequence that is at least 90% identical to SEQ ID NO: 47 having signal sequence activity; or

has an amino acid sequence that is at least 90% identical to SEQ ID NO: 24 having signal sequence activity.

4. The recombinant yeast host cell of claim 3 , wherein the heterologous polypeptide:

has an amino acid sequence according to SEQ ID NO: 29 having glucoamylase activity;

has an amino acid sequence according to SEQ ID NO: 5 having glucoamylase activity;

has an amino acid sequence according to SEQ ID NO: 31 having glucoamylase activity;

has an amino acid sequence according to SEQ ID NO: 43 having glucoamylase activity;

has an amino acid sequence according to SEQ ID NO: 45 having glucoamylase activity; or

has an amino acid sequence according to SEQ ID NO: 49 having glucoamylase activity.

5. The recombinant yeast host cell of claim 2 , wherein the heterologous nucleic acid molecule further comprises a third polynucleotide comprising a heterologous promoter operatively associated with the first polynucleotide and the second polynucleotide allowing the expression of the heterologous polypeptide having glucoamylase activity.

6. The recombinant yeast host cell of claim 5 , wherein the third polynucleotide comprises a tef2p, a adh1p and/or a qcr8p.

7. The recombinant yeast host cell of claim 1 , wherein the heterologous polypeptide having glucoamylase activity is a secreted polypeptide, a membrane-associated polypeptide, and/or a tethered polypeptide.

8. The recombinant yeast host cell of claim 1 which is from species Saccharomyces cerevisiae.

9. A composition comprising the recombinant yeast host cell of claim 1 and raw starch.

10. A process for saccharification and fermentation of a biomass into a fermentation product, the process comprises contacting the biomass with the recombinant yeast host cell of claim 1 , under a condition that allows conversion of at least a part of the biomass into the fermentation product.

11. The process of claim 10 , wherein the biomass is derived from or comprises corn, potato, cassava, rice, wheat, lignocellulosic material or buckwheat.

12. The process of claim 10 , wherein the biomass is derived from or comprises corn.

13. The process of claim 12 , wherein the biomass comprises or is corn mash.

14. The process of claim 12 , wherein the biomass comprises or is raw starch.

15. The process of claim 10 , wherein the fermentation product is ethanol.

16. The process of claim 10 , wherein the fermentation is conducted in the presence of a stressor comprising low pH and/or an elevated temperature.