Screening and Genotypic Characterization of Lactic Cultures Isolated from Fermented Idli Batter

Abstract

The present study was conducted during 2021-22 at Dairy Science College, Bangalore, India to study the microflora present in fermented control idli batter and batter added with paneer whey and characterize them to use as solid-state fermentation cultures for idli batter fermentation. Eighteen isolates were screened for their phenotypic characteristics after enumeration of microflora in ingredients and fermented batter. The paneer whey was used at 70% of the water used as value addition and by-product utilization for enhancing the nutritional quality of idli. Further, these lactic cultures were screened for their activity for acid production and DMC in the whey-based medium. Titratable acidity ranged from 0.42 to 0.70% lactic acid with a highest of 0.70 for Lb1 and lowest of 0.42 for Leu6 and W4 isolates. DMC was highest at 8.01 log10 cells/ml for E1 isolate and lowest at 7.41 log10 cells/ml for W4 with a range from 7.41 to 8.01 log10 cells/ml. The isolates with code numbers Lb1, Lb2, Leu2, and E1 showed higher titratable acidity and DMC. DNA extracted from the selected four isolates was subjected to PCR and PCR products were sequenced. Based on the results obtained species of isolates were identified as Leuconostoc sp. strain Leu2, Enterococcus sp. strain E1, Lactobacillus brevis strain Lb1, and Lactobacillus casei strain Lb2. The nucleotide sequences of 16S rRNA were submitted to GenBank of NCBI and obtained accession numbers as MW 386845.1, MW386871.1, MW480882.1, and MW485119.1 respectively. These isolates were further used as solid-state fermentation cultures for idli batter fermentation.