The invention provides recombinant algal mutants that have a genetic modification to a gene or nucleic acid sequence encoding a WD40 repeat containing protein or domain. The genetic modification of one or more nucleic acid sequences encoding a WD40 repeat containing protein or domain results in a mutant organism with increased lipid productivity and/or higher biomass productivity (as measured by total organic carbon). The genetic modification can be a gene attenuation or functional deletion. The lipid products of these mutants can be utilized as biofuels or for other specialty chemical products. Methods of making and using the recombinant algal mutants and methods of producing lipids are also disclosed.