Physicochemical and Microbial Diversity Analyses of Indian Hot Springs.

Manik Prabhu Narsing Rao,Wen-Jun Li,Shu-Xian Guo,Wael N Hozzein,Zhou-Yan Dong,Zhen-Hao Luo,Min Xiao,Meng-Meng Li,Bing-Bing Liu

doi:10.3389/fmicb.2021.627200

Abstract

In the present study, physicochemical and microbial diversity analyses of seven Indian hot springs were performed. The temperature at the sample sites ranged from 32 to 67°C, and pH remained neutral to slightly alkaline. pH and temperature influenced microbial diversity. Culture-independent microbial diversity analysis suggested bacteria as the dominant group (99.3%) when compared with the archaeal group (0.7%). Alpha diversity analysis showed that microbial richness decreased with the increase of temperature, and beta diversity analysis showed clustering based on location. A total of 131 strains (divided into 12 genera and four phyla) were isolated from the hot spring samples. Incubation temperatures of 37 and 45°C and T5 medium were more suitable for bacterial isolation. Some of the isolated strains shared low 16S rRNA gene sequence similarity, suggesting that they may be novel bacterial candidates. Some strains produced thermostable enzymes. Dominant microbial communities were found to be different depending on the culture-dependent and culture-independent methods. Such differences could be attributed to the fact that most microbes in the studied samples were not cultivable under laboratory conditions. Culture-dependent and culture-independent microbial diversities suggest that these springs not only harbor novel microbial candidates but also produce thermostable enzymes, and hence, appropriate methods should be developed to isolate the uncultivated microbial taxa.

Highlights

Hot springs are the places where warm or hot groundwater comes out from the Earth (Narsing Rao et al, 2018)
The results suggest that temperature plays an important role in structuring hot spring microbial diversity
The result suggests that physicochemical parameters play an important role in shaping the microbial community of hot springs, and these parameters should be considered during isolation

Summary

Introduction

Hot springs are the places where warm or hot groundwater comes out from the Earth (Narsing Rao et al, 2018). Researchers around the world have begun to study similar ecosystems using a culture-dependent approach to understand microbial diversity (Baker et al, 2001; Pathak and Rathod, 2014; Liu et al, 2016). Microbial diversity analysis was carried out by the traditional culture-dependent method; this method has several disadvantages. Most of the microorganisms in this method remain hidden or difficult to grow (Kumar et al, 2004; Najar et al, 2018; Narsing Rao et al, 2018). In the past few years, this method played an important role in understanding the microbial diversity of various ecological niches (Ghelani et al, 2015; De Mandal et al, 2017; Anguita-Maeso et al, 2020)

Methods

Results

Discussion

Conclusion