ACID-PRODUCING BACTERIA AND YEASTS ISOLATED FROM ARABICA COFFEE PLANTATIONS IN CENTRAL JAVA']JAVA AND EAST JAVA']JAVA, INDONESIA

The converting process of coffee cherries to green coffee beans before roasting was conducted through fermentation using lactic acid bacteria (LAB) and yeasts to degrade coffee's mucilage. This present study aims to isolate acid-producing bacteria and yeasts from three types of samples obtained from arabica coffee plantations in Central Java and East Java, Indonesia. One sample from feces of luwak or civet (Paradoxurus hermaphroditus), two samples from exocarp of arabica's coffee fruits, and one sample from the soil in the rhizosphere of a coffee tree. Enrichment method by using MRS broth supplemented with 0.5% calcium carbonate was used for obtaining acid producing bacteria and yeasts. Phylogenetic tree based on 16S rRNA gene for bacteria and 26S rRNA gene for yeast were constructed and analyzed. The screening of their ability to produce acid was conducted by using MRS agar supplemented with 0.5% calcium carbonate. A total of 31 bacteria and 15 yeasts were obtained from this study. From 31 bacteria, 15 strains were identified as Pediococcus pentosaceus, 6 strains as Lactobacillus sp., 4 strains as Leuconostoc pseudomesenteroides, 5 strains as Acetobacter tropicalis; and 1 strain as Klebsiella quasipneumoniae. While from 15 yeasts, 8 strains were identified as Candida tropicalis, 2 strains as Pichia kudriavzevii, and 5 strains as Cyberlindnera fabianii. A total of 25 strains of lactic acid bacteria were able to release lactic acid on MRS agar supplemented with 0.5% CaCO3, but 5 strains of A. tropicalis and 1 strain of K. quasipneumoniae produced acid weakly. Four strains of C. tropicalis showed the ability to form a thin clear zone in contrast to the other of four yeast strains. This study revealed that samples from the coffee plantation areas are potential sources to obtain acid-producing bacteria which can be utilized in fermentation process of coffee cherries.