Microbial diversity of thermophiles with biomass deconstruction potential in a foliage-rich hot spring.

Li Sin Lee,Wai‐Fong Yin,Chia Sing Chan,Chun Shiong Chong,Kok‐Gan Chan,Geok Yuan Annie Tan,Kian Mau Goh

doi:10.1002/mbo3.615

Li Sin Lee, Wai‐Fong Yin + Show 5 more

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https://doi.org/10.1002/mbo3.615

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Abstract

The ability of thermophilic microorganisms and their enzymes to decompose biomass have attracted attention due to their quick reaction time, thermostability, and decreased risk of contamination. Exploitation of efficient thermostable glycoside hydrolases (GHs) could accelerate the industrialization of biofuels and biochemicals. However, the full spectrum of thermophiles and their enzymes that are important for biomass degradation at high temperatures have not yet been thoroughly studied. We examined a Malaysian Y‐shaped Sungai Klah hot spring located within a wooded area. The fallen foliage that formed a thick layer of biomass bed under the heated water of the Y‐shaped Sungai Klah hot spring was an ideal environment for the discovery and analysis of microbial biomass decay communities. We sequenced the hypervariable regions of bacterial and archaeal 16S rRNA genes using total community DNA extracted from the hot spring. Data suggested that 25 phyla, 58 classes, 110 orders, 171 families, and 328 genera inhabited this hot spring. Among the detected genera, members of Acidimicrobium, Aeropyrum, Caldilinea, Caldisphaera, Chloracidobacterium, Chloroflexus, Desulfurobacterium, Fervidobacterium, Geobacillus, Meiothermus, Melioribacter, Methanothermococcus, Methanotorris, Roseiflexus, Thermoanaerobacter, Thermoanaerobacterium, Thermoanaerobaculum, and Thermosipho were the main thermophiles containing various GHs that play an important role in cellulose and hemicellulose breakdown. Collectively, the results suggest that the microbial community in this hot spring represents a good source for isolating efficient biomass degrading thermophiles and thermozymes.

Highlights

Lignocellulolytic biomass is a sustainable resource for second- generation biofuel production (Xia, Ju, Fang, & Zhang, 2013)
The data and results obtained add to the list of important thermophiles for biomass degradation at high temperatures, suggesting that the microbial populations involved in biomass degradation in natural environments are far more complicated than in laboratory setups
We found that the following thermophilic bacterial genera have an abundance of genes encoded for 61 glycoside hydrolases (GHs) sequences: Acidimicrobium, Caldilinea, Chloracidobacterium, Chloroflexus, Desulfurobacterium, Fervidobacterium, Geobacillus, Meiothermus, Melioribacter, Roseiflexus, Thermoanaerobacter, Thermoanaerobacterium, Thermoanaerobaculum, and Thermosipho

Summary

| INTRODUCTION

Lignocellulolytic biomass is a sustainable resource for second- generation biofuel production (Xia, Ju, Fang, & Zhang, 2013). When OBP10 samples were inoculated with various lignocellulolytic materials, including Avicel, switchgrass, Populus, and xylan, and incubated at 55–85°C in anaerobic laboratory conditions, the main bacteria after three culturing rounds were Thermoanaerobacter, Caloramator, Caldicellulosiruptor, Clostridium, Dictyoglomus, and Fervidobacterium; their distributions in these experiments varied with experimental parameters such as temperature and type of substrate (Vishnivetskaya et al, 2015). Another site that lacks lignocellulosic plant material is the Great Boiling Spring (GBS), located in Nevada (77–85°C) (Peacock et al, 2013). The data and results obtained add to the list of important thermophiles for biomass degradation at high temperatures, suggesting that the microbial populations involved in biomass degradation in natural environments are far more complicated than in laboratory setups

| MATERIALS AND METHODS

| DISCUSSION

Findings

| CONCLUSIONS