Isolation and characterization of Pediococcus sp. HLV1 from fermented idly batter

The aim of the present study is the isolation and characterization of the lactic acid bacteria from idly batter, a traditional Indian fermented product. To achieve the aim, 10 idly batter samples were selected from different regions of Kadapa district. In the primary isolation and screening process, 50 lactic-acid-producing bacteria were isolated, and from them, six strains were selected based on their lactic acid yielding capacity for further evaluation. The selected cultures were studied for their phenotypic characters, and all cultures were Gram positive, cocci, and catalase negative. All the six strains were tested for their growth and lactic acid production at above 35 ◦C, and finally, one strain that showed good growth at 50 ◦C was selected for further characterization. Molecular characterization by 16S rRNA gene analysis and BLAST analysis revealed 99% similarity with Pediococcus pentosaceus Ni1142. The isolated culture was named as Pediococcus sp. HLV1, and the sequence was submitted to the NCBI databank as accession number MH921241. The isolated strain is able to utilize a wide range of carbohydrate substrates including glucose, fructose, sucrose, lactose, maltose, and xylose. The major fermentation product from glucose is lactic acid. Pediococcus sp. HLV1 showed optimum growth and production of lactic acid with glucose as carbon source (10%) and yeast extract as nitrogen source (0.3%) at pH 7.0 and 40 ◦C. As well-known probiotic bacteria, the isolated Pediococcus spp. also showed antimicrobial activity against both Gram-positive and Gram-negative bacteria and more specifically inhibited Gram-positive Bacillus. Using the above optimal conditions, lactic acid from a fresh mango peel extract was studied, and at the end of the fermentation, 5.2% (v/v) of lactic acid was produced. In conclusion, the isolated LAB Pediococcus sp. strain HLV1 is able to grow and produce lactic acid at a high temperature (45 ◦C) and to survive at 50 ◦C. Mango peel, a by-product of mango pulp industries, can be utilized as one of the economically cheap feedstocks for industrial production of lactic acid by the Pediococcus sp. strain HLV1.