The present invention relates to microorganisms genetically engineered to increase yield and/or efficiency of biomass production from a carbon source, such as e.g. glucose. Processes for generating such microorganisms are also provided by the present invention. The invention also relates to polynucleotide sequences comprising genes that encode proteins that are involved in the bioconversion of a carbon source such as e.g. glucose into biomass. The invention also features polynucleotides comprising the full-length polynucleotide sequences of the novel genes and fragments thereof, the novel polypeptides encoded by the polynucleotides and fragments thereof, as well as their functional equivalents. Also included are processes of using the polynucleotides and modified polynucleotide sequences to transform host microorganisms leading to a microorganism with reduced carbon source diversion, i.e. higher yield and/or efficiency of biomass production from a carbon source such as e.g. glucose.