Patent 8357527 was granted and assigned to AMYRIS, INC. on January, 2013 by the United States Patent and Trademark Office.
Provided herein are methods of generating genetically modified microorganisms, e.g., genetically modified yeast strains, which comprise functional disruptions in one or more pheromone response genes and one or more sporulation genes, and genetically modified yeast cells, e.g., genetically modified diploid and haploid yeast cells, that lack sporulation capability and endogenous mating capability, produced thereby.