Isolation and screening of amylase activity of primary moulds in Ragi Tapai of Indonesia

Abstract

Primary moulds involved in tapai fermentation have been isolated on Potato Dextrose Agar (PDA) supplemented with tetracycline. Fifteen different ragi tapai samples used in the experiment were collected from West Java, Central Java and outside Java. A total of 56 mould isolates have been isolated consisting of 13 isolates from ragi tapai of West Java, 21 isolates from ragi tapai of Central Java, and 22 isolates from ragi tapai of outside Java. The isolates were cultured on PDA medium and screened. Amylase activity was determined by iodine method and measured for the diameter of clear zone. Based on screening of amylase activity, isolates ZC1 (69.95 mm) from ragi tapai of West Java, ZSL3 (58.1 mm) from ragi tapai of Central Java, and ZMDN1 (85.00 mm) from ragi tapai of outside Java were the most potential showing the widest diameter of clear zone. Macroscopic and microscopic observation of the isolates showed isolates ZC1 and ZSL3 belong to genus Rhizopus while isolate ZMDN1 belongs to genus Amylomyces.