Desain Primer, Isolasi, dan Amplifikasi Gen Beta Glukan Sintase (FKS) dari Jamur Tiram Putih (Pleurotus ostreatus (Jacq) P. Kummer 1871) = Primer Design, Isolation, and Amplification of Beta Glucan Synthase Gene (FKS) from White Oyster Mushroom (Pleurotus ostreatus (Jacq.) P. Kumm. 1871)