The microbial ecology of tape ketan fermentation.

The growth of fungi, yeasts and bacteria was followed during the fermentation of tape ketan. The tape was prepared using samples of Indonesian ragi as inoculum. Fermentation was characterized by the dominant growth of Amylomyces rouxii and Candida pelliculosa (10(5)-10(7) cfu/g), and a lesser contribution from Saccharomyces cerevisiae. Hansenula anomala grew to a limited extent during some fermentations. Bacteria of the genera Bacillus and Acetobacter contributed also to the fermentation, producing populations up to 10(5) cfu/g. Ragi was the main source of microorganisms involved in the fermentation. Tape fermented by inoculating pure cultures of Amylomyces rouxii and the yeasts, either individually or as mixtures, was not of typical quality, indicating the importance of bacteria in the overall fermentation.