Bacteria Responsible for Mucilage-Layer Decomposition in Kona Coffee Cherries

The predominant microbial flora present during decomposition of the mucilage layer of Kona coffee cherries were gram-negative bacteria which fermented lactose rapidly. Cultures isolated from coffee cherries under-going fermentation included species ofErwinia, Paracolobactrum , andEscherichia . Unblemished cherry surfaces and coffee plantation soil also had a microflora containing a high proportion of bacteria belonging to these three genera. Of 168 isolates tested, the 44 strains capable of demucilaging depulped coffee cherries were all members ofErwinia dissolvens . Supernatant growth medium liquids, after removal ofE. dissolvens cells, actively decomposed the mucilage layer of depulped cherries.