Not All That Glitters Is Gold: The Paradox of CO-dependent Hydrogenogenesis in Parageobacillus thermoglucosidasius.

Habibu Aliyu,Pieter De Maayer,Anke Neumann

doi:10.3389/fmicb.2021.784652

Habibu Aliyu, Pieter De Maayer + Show 1 more

Open Access

https://doi.org/10.3389/fmicb.2021.784652

Copy DOI

Abstract

The thermophilic bacterium Parageobacillus thermoglucosidasius has recently gained interest due to its ability to catalyze the water gas shift reaction, where the oxidation of carbon monoxide (CO) is linked to the evolution of hydrogen (H2) gas. This phenotype is largely predictable based on the presence of a genomic region coding for a carbon monoxide dehydrogenase (CODH—Coo) and hydrogen evolving hydrogenase (Phc). In this work, seven previously uncharacterized strains were cultivated under 50% CO and 50% air atmosphere. Despite the presence of the coo—phc genes in all seven strains, only one strain, Kp1013, oxidizes CO and yields H2. The genomes of the H2 producing strains contain unique genomic regions that code for proteins involved in nickel transport and the detoxification of catechol, a by-product of a siderophore-mediated iron acquisition system. Combined, the presence of these genomic regions could potentially drive biological water gas shift (WGS) reaction in P. thermoglucosidasius.

Highlights

The genus Parageobacillus comprises a phylogenetically coherent group of thermophilic and facultative anaerobes in the family Bacillaceae (Suzuki et al, 1983; Aliyu et al, 2016, 2018; Oren and Garrity, 2019)
RNA-seq Data Suggest Activity of HSUL 1 and 2 During Water Gas Shift Reaction in Parageobacillus thermoglucosidasius DSM 6285 To speculate on the potential activity of the above genomic regions under water gas shift (WGS) reaction conditions, we evaluated the previously reported P. thermoglucosidasius DSM 6285 transcriptome data
Cultivation experiments with P. thermoglucosidasius strains that have not been previously characterized for WGS reaction showed that the ability to oxidize carbon monoxide (CO) is highly restricted in this species

Summary

Introduction

The genus Parageobacillus comprises a phylogenetically coherent group of thermophilic (growth Topt range of 50–65◦C) and facultative anaerobes in the family Bacillaceae (Suzuki et al, 1983; Aliyu et al, 2016, 2018; Oren and Garrity, 2019) They share many features, including growth temperature requirement (obligate thermophiles) with their closest relatives in the genus Geobacillus, Parageobacillus species are distinguished by a characteristic low genomic G + C content and a distinct phylogenetic clustering among several other phylogenomic features (Aliyu et al, 2016, 2018). Due to its catabolic versatility (Hussein et al, 2015), P. thermoglucosidasius grows optimally on a range of carbohydrates, ranging

Objectives

Methods

Results

Conclusion