Yeast community profiling of fermenting nipa (Nypa fruticans) sap in two philippine locations and fermentation characteristics of selected yeasts
Abstract
© 2019, College of Agriculture and Food Science, University of the Philippines Los Banos. All rights reserved. Naturally fermenting nipa (Nypa fruticans) sap samples from two lambanog (palm liquor)-making sites in the Philippines were subjected to yeast community analysis. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis revealed six (6) yeast strains participating in nipa sap fermentation in the two sites. The nipa sap samples from Pamplona, Cagayan samples showed more yeast variability compared with the Mauban, Quezon samples. The dominant yeasts are Saccharomyces cerevisiae in Mauban and Saccharomycodes spp. in Pamplona. The culturable yeast isolates were purified and categorized into four (4) groups based on their banding patterns that were generated by means of microsatellite (GTG)5 fingerprinting. Yeast strains isolated from spontaneous nipa sap fermentations were identified by sequencing of the D1/D2 domain of the 26S rRNA gene and the ITS1-5.8S-ITS2 region, in which three (3) were S. cerevisiae and one (1) was Pichia kudriavzevii. These representative yeast isolates were subjected to various stress tolerance tests and evaluated for their ability to produce ethanol. P. kudriavzevii was most tolerant to pH 2.0 and 40 °C. On the other hand, S. cerevisiae produced higher ethanol compared with P. kudriavzevii.