Functional screening and molecular characterization of halophilic and halotolerant bacteria by 16s rRNA gene sequence analysis.

Abstract

A total of 206 bacterial isolates were obtained from soil, water and sediment samples using three different culture media with a pH of 7.3 ± 0.2 and an incubation temperature of 37 °C. Of these isolates, 48 bacteria were selected for functional screening and molecular characterization. The functional screening for salt stress tolerance revealed that, 17 bacteria were identified as moderately halotolerant and 31 were halophilic, capable of growing at 5–15 % (w/v) and ≥15 % (w/v) of NaCl concentration respectively. The 16S rRNA gene sequence analysis and taxonomic identification of isolates were performed using Ribosomal Database Project Release-10 and SILVA SSU database. Based on the sequence length >1,300 bp, 40 bacteria were identified out of 48 isolates. Study showed that, Staphylococcus spp. was highly resistant to salt stress followed by Enterococcus faecalis, Vagococcus fluvialis and Vibrio parahaemolyticus. The phylogenetic analysis revealed that, 24 bacterial isolates belong to Firmicutes and 16 isolates come under Proteobacteria. These bacterial strains would be of great use for prospecting novel and candidate salt stress tolerant genes