Microbiological Study During Coffee Fermentation of Coffea arabica var. chiangmai 80 in Thailand

Abstract

This study investigated the microbial communities during coffee fermentation using the wet method for Coffea arabica var. chiangmai 80 which has been widely grown in northern Thailand. The coffee cherries and the depulped coffee samples were collected during fermentation from four processing areas. The fermentation tank pH decreased from 6.27 to 4.00 after 48 hr fermentation. Bacteria were the most abundant microorganisms found throughout the process. The most common bacteria were members of Enterobacteriaceae such as Enterobacter agglomerans, Erwinia dissolvens, Escherichia coli and Klebsiella pneumonia. In addition, lactic acid bacteria were frequently found throughout fermentation and included Leuconostoc mesenteroides, Lactobacillus brevis, Lactococcus plantarum and Enterococcus casseliflavus. Gram-positive spore forming bacteria such as Bacillus subtilis and B. cereus were also found during fermentation. The number of yeasts increased after 24 hr fermentation. Candida, Pichia, Debaryomyces, Kluyveromyces and Saccharomyces were the most common yeast genera. Filamentous fungi were minimal during the fermentation. Penicillium was the most common fungi in this study. The genera and species identified include members known to have pectinolytic activity. These microorganisms may be used to improve coffee fermentation or to produce pectinolytic enzyme for industrial purposes. Moreover, some had the ability to produce a special aroma.