AUTHOR=Kim Hye Won , Kim Na Kyung , Phillips Alex P. R. , Parker David A. , Liu Ping , Whitaker Rachel J. , Rao Christopher V. , Mackie Roderick I. 

TITLE=Genomic insight and physiological characterization of thermoacidophilic Alicyclobacillus isolated from Yellowstone National Park

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1232587

DOI=10.3389/fmicb.2023.1232587

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p><italic>Alicyclobacillus</italic> has been isolated from extreme environments such as hot springs, volcanoes, as well as pasteurized acidic beverages, because it can tolerate extreme temperatures and acidity. In our previous study, <italic>Alicyclobacillus</italic> was isolated during the enrichment of methane oxidizing bacteria from Yellowstone Hot Spring samples.</p></sec><sec><title>Methods</title><p>Physiological characterization and genomic exploration of two new <italic>Alicyclobacillus</italic> isolates, AL01A and AL05G, are the main focus of this study to identify their potential relationships with a thermoacidophilic methanotroph (<italic>Methylacidiphilum</italic>) isolated from the same hot spring sediments.</p></sec><sec><title>Results and discussion</title><p>In the present study, both <italic>Alicyclobacillus</italic> isolates showed optimal growth at pH 3.5 and 55°C, and contain ω-alicyclic fatty acids as a major lipid (<italic>ca.</italic> 60%) in the bacterial membrane. Genomic analysis of these strains revealed specific genes and pathways that the methanotroph genome does not have in the intermediary carbon metabolism pathway such as <italic>serC</italic> (phosphoserine aminotransferase), <italic>comA</italic> (phosphosulfolactate synthase), and DAK (glycerone kinase). Both <italic>Alicyclobacillus</italic> strains were also found to contain transporter systems for extracellular sulfate (ABC transporter), suggesting that they could play an important role in sulfur metabolism in this extreme environment. Genomic analysis of vitamin metabolism revealed <italic>Alicyclobacillus</italic> and <italic>Methylacidiphilum</italic> are able to complement each other’s nutritional deficiencies, resulting in a mutually beneficial relationship, especially in vitamin B<sub>1</sub>(thiamin), B<sub>3</sub> (niacin), and B<sub>7</sub> (biotin) metabolism. These findings provide insights into the role of <italic>Alicyclobacillus</italic> isolates in geothermal environments and their unique metabolic adaptations to these environments.</p></sec>