Role of pectinolytic yeasts in the degradation of mucilage layer of Coffea robusta cherries.

Pectinolytic yeasts, Saccharomyces marxianus, S. bayanus, S. cerevisiae var. ellipsoideus, and Schizosaccharomyces sp., predominated in the natural fermentation of coffee cherries of Coffea robusta variety grown in Chikmagalur district of Mysore State, India. These yeast species were found on the cherry surfaces, and evidence was adduced to show that the natural fermentation of coffee was the result of activity of microflora from the cherry surface itself rather than that of flora of air or water. Incorporation of pure cultures of Saccharomyces species was shown to aid the process when a mixture of all three species was used. An enzyme preparation from the Saccharomyces species was observed to hasten the mucilage-layer degradation.