The present disclosure relates generally to methods, isolated polypeptides and polynucleotides, expression vectors, and host cells for the production of olivetolic acid and phytocannabinoids. A method of producing olivetolic acid (OVLa) and/or a phytocannabinoid in a heterologous host cell having OVLa-producing or phytocannabinoid-producing capacity comprises transforming the host cell with a nucleotide encoding a variant olivetolic acid cyclase (OAC) protein having at least 6 amino acid mutations relative to the wild type OAC protein, and culturing the transformed host cell to produce OVLa and/or phytocannabinoids therefrom. The variant OAC protein (SEQ ID NO:92) has at least 85% sequence identity with the wild type OAC protein (SEQ ID NO:91). Exemplary variants having improved OVLa or phytocannabinoid production capacity are described.