Thermophilic methane oxidation is widespread in Aotearoa-New Zealand geothermal fields.

Geothermal areas represent substantial point sources for greenhouse gas emissions such as methane. While it is known that methanotrophic microorganisms act as a biofilter, decreasing the efflux of methane in most soils to the atmosphere, the diversity and the extent to which methane is consumed by thermophilic microorganisms in geothermal ecosystems has not been widely explored. To determine the extent of biologically mediated methane oxidation at elevated temperatures, we set up 57 microcosms using soils from 14 Aotearoa-New Zealand geothermal fields and show that moderately thermophilic (>40°C) and thermophilic (>60°C) methane oxidation is common across the region.

Growth on Formic Acid Is Dependent on Intracellular pH Homeostasis for the Thermoacidophilic Methanotroph sp. RTK17.1.

Members of the genus , a clade of metabolically flexible thermoacidophilic methanotrophs from the phylum Verrucomicrobia, can utilize a variety of substrates including methane, methanol, and hydrogen for growth. However, despite sequentially oxidizing methane to carbon dioxide methanol and formate intermediates, growth on formate as the only source of reducing equivalents (i.e.

Temperature-gradient incubation isolates multiple competitive species from a single environmental sample.

High-throughput sequencing has allowed culture-independent investigation into a wide variety of microbiomes, but sequencing studies still require axenic culture experiments to determine ecological roles, confirm functional predictions and identify useful compounds and pathways. We have developed a new method for culturing and isolating multiple microbial species with overlapping ecological niches from a single environmental sample, using temperature-gradient incubation. This method was more effective than standard serial dilution-to-extinction at isolating methanotrophic bacteria.

Thermophilic methanotrophs: in hot pursuit.

Methane is a potent greenhouse gas responsible for 20-30% of global climate change effects. The global methane budget is ∼500-600 Tg y-1, with the majority of methane produced via microbial processes, including anthropogenic-mediated sources such as ruminant animals, rice fields, sewage treatment facilities and landfills. It is estimated that microbially mediated methane oxidation (methanotrophy) consumes >50% of global methane flux each year.

Interaction between ferruginous clay sediment and an iron-reducing hyperthermophilic Pyrobaculum sp. in a terrestrial hot spring.

Green-coloured sediments in low-temperature geothermal surface features are typically indicative of photosynthetic activity. A near-boiling (89-93°C), alkali-chloride spring in the Taupō Volcanic Zone, New Zealand, was observed to have dark green sediments despite being too hot to support any known photosynthetic organisms. Analysis of aqueous and sediment microbial communities via 16S rRNA amplicon sequencing revealed them to be dominated by Aquifex spp.

Mixotrophy drives niche expansion of verrucomicrobial methanotrophs.

Aerobic methanotrophic bacteria have evolved a specialist lifestyle dependent on consumption of methane and other short-chain carbon compounds. However, their apparent substrate specialism runs contrary to the high relative abundance of these microorganisms in dynamic environments, where the availability of methane and oxygen fluctuates. In this work, we provide in situ and ex situ evidence that verrucomicrobial methanotrophs are mixotrophs.

Thermorudis pharmacophila sp. nov., a novel member of the class Thermomicrobia isolated from geothermal soil, and emended descriptions of Thermomicrobium roseum, Thermomicrobium carboxidum, Thermorudis peleae and Sphaerobacter thermophilus.

An aerobic, thermophilic and cellulolytic bacterium, designated strain WKT50.2T, was isolated from geothermal soil at Waikite, New Zealand. Strain WKT50.

Novel long-chain diol phospholipids from some bacteria belonging to the class Thermomicrobia.

Polar lipids of bacteria from the class Thermomicrobia are known to contain long-chain 1,2-diols instead of glycerol, although the nature of polar head groups has not been investigated. We have studied phospholipid classes of two species from the class Thermomicrobia-Sphaerobacter thermophilus and Thermomicrobia sp. WKT50.

The identification and quantification of phospholipids from Thermus and Meiothermus bacteria.

Structural identities of the major phospholipid (PL-2), minor phospholipid (PL-1) and trace phospholipid (PL-0) from representative strains of the genera Thermus and Meiothermus were established. Phospholipids were quantified using phosphorus-31 nuclear magnetic resonance ((31)P-NMR). The structures of the major phospholipid (PL-2) from Thermus filiformis MOK14.

Ether- and ester-bound iso-diabolic acid and other lipids in members of acidobacteria subdivision 4.

Recently, iso-diabolic acid (13,16-dimethyl octacosanedioic acid) has been identified as a major membrane-spanning lipid of subdivisions 1 and 3 of the Acidobacteria, a highly diverse phylum within the Bacteria. This finding pointed to the Acidobacteria as a potential source for the bacterial glycerol dialkyl glycerol tetraethers that occur ubiquitously in peat, soil, lakes, and hot springs. Here, we examined the lipid composition of seven phylogenetically divergent strains of subdivision 4 of the Acidobacteria, a bacterial group that is commonly encountered in soil.

Thermoflavifilum aggregans gen. nov., sp. nov., a thermophilic and slightly halophilic filamentous bacterium from the phylum Bacteroidetes.

A strictly aerobic, thermophilic, moderately acidophilic, non-spore-forming bacterium, strain P373(T), was isolated from geothermally heated soil at Waikite, New Zealand. Cells were filamentous rods, 0.2-0.

Chthonomonas calidirosea gen. nov., sp. nov., an aerobic, pigmented, thermophilic micro-organism of a novel bacterial class, Chthonomonadetes classis nov., of the newly described phylum Armatimonadetes originally designated candidate division OP10.

An aerobic, saccharolytic, obligately thermophilic, motile, non-spore-forming bacterium, strain T49(T), was isolated from geothermally heated soil at Hell's Gate, Tikitere, New Zealand. On the basis of 16S rRNA gene sequence similarity, T49(T) is the first representative of a new class in the newly described phylum Armatimonadetes, formerly known as candidate division OP10. Cells of strain T49(T) stained Gram-negative and were catalase-positive and oxidase-negative.