Abstract: The invention is directed to non-natural yeast able to secrete significant amounts of glucoamylase into a fermentation media. The glucoamylase can promote degradation of starch material generating glucose for fermentation to a desired bioproduct, such as ethanol. The glucoamylase can be provided in the form of a glucoamylase fusion protein having a S. cerevisiae mating factor alpha 2 (Sc MF?2) or repressible acid phosphatase (Sc PHO5) secretion signal.

Abstract: The present invention relates to genetically modified yeasts that can use lactate as a carbon source to produce a fermentation product. In one aspect, the yeasts can consume gluconse and lactate simultaneously to produce ethanol. In one aspect, the genetically modified yeast is transformed to include a monocarboxylic/monocarboxylate transporter. In one aspect, the yeast can include one or more heterologous genes encoding lactate dehydrogenase (cytochrome) (EC 1.1.2.3 and/or 1.1.2.4).

Abstract: Genetically engineered yeast with a heterologous glucoamylase and fermentation methods are described. The engineered yeast can have multiple exogenous nucleic acid sequences which each have a different sequence, but that encode the same or a similar glucoamylase protein that is heterologous to the yeast. The engineered yeast exhibit desirable bioproduct production profiles during a fermentation process. A fermentation medium with a starch material can be fermented with the engineered yeast to provide high ethanol titers, low glycerol titers, or both.

Abstract: The invention is directed to non-natural yeast able to secrete significant amounts of glucoamylase into a fermentation media. The glucoamylase can promote degradation of starch material generating glucose for fermentation to a desired bioproduct, such as ethanol. The glucoamylase can be provided in the form of a glucoamylase fusion protein having a S. cerevisiae mating factor alpha 2 (Sc MF?2) or repressible acid phosphatase (Sc PHO5) secretion signal.