Methanofollis fontis sp. nov., a methanogen isolated from marine sediment near a cold seep at Four-Way Closure Ridge offshore southwestern Taiwan

Recovery capability of anaerobic digestion from ammonia stress: Metabolic activity, energy generation, and genome-centric metagenomics

Excessive ammonia stresses anaerobic digestion (AD) significantly. Although there has been progress in understanding AD under ammonia exposure, investigations on AD liberated from ammonia exposure are limited. Here, the recovery capability of AD from ammonia stress was evaluated, by examining specific methanogenic activity, energy-conserving capability, microbial community succession, and metabolic pathway reconstruction. The findings demonstrated that ammonia stress relief resulted in < 50% methane recovery, with propionate conversion identified as the critical impediment to AD reactivation. Energy generation could not recovered either. Efforts to mitigate ammonia stress failed to restore acetoclastic methanogens, e.g., Methanothrix soehngenii, and proved futile in awakening propionate oxidizers, e.g., Desulfobulbus. Interestingly, a symbiotic metabolism emerged, prevailing in stress-relieved AD due to its energy-conserving advantage. This study underscores the importance of targeted interventions, including stimulating acetoclastic methanogenesis, propionate oxidation, and energy generation, as priorities for AD recovery following ammonia stress, rather than focusing solely on ammonia level management.

The complete genome sequence of Kineothrix sp. MB12-C1, isolated from the feces of black soldier fly larvae

Here, we present the complete genome sequence of Kineothrix sp. MB12-C1 (= BCRC 81406), isolated from the feces of black soldier fly (Hermetia illucens) larvae. The genome of strain MB12-C1 was chosen for further species classification and comparative genomic analysis.

Complete genome sequence of Proteiniborus sp. MB09-C3, isolated from the feces of the black soldier fly larvae

Here, we report the complete genome sequence of Proteiniborus sp. MB09-C3 (= BCRC 81405), isolated from the feces of black soldier fly (Hermetia illucens) larvae. The genome of strain MB09-C3 was selected for further species delineation and comparative genomic analysis.

Well-hidden methanogenesis in deep, organic-rich sediments of Guaymas Basin

Deep marine sediments (>1mbsf) harbor ~26% of microbial biomass and are the largest reservoir of methane on Earth. Yet, the deep subsurface biosphere and controls on its contribution to methane production remain underexplored. Here, we use a multidisciplinary approach to examine methanogenesis in sediments (down to 295 mbsf) from sites with varying degrees of thermal alteration (none, past, current) at Guaymas Basin (Gulf of California) for the first time. Traditional (13C/12C and D/H) and multiply substituted (13CH3D and 12CH2D2) methane isotope measurements reveal significant proportions of microbial methane at all sites, with the largest signal at the site with past alteration. With depth, relative microbial methane decreases at differing rates between sites. Gibbs energy calculations confirm methanogenesis is exergonic in Guaymas sediments, with methylotrophic pathways consistently yielding more energy than the canonical hydrogenotrophic and acetoclastic pathways. Yet, metagenomic sequencing and cultivation attempts indicate that methanogens are present in low abundance. We find only one methyl-coenzyme M (mcrA) sequence within the entire sequencing dataset. Also, we identify a wide diversity of methyltransferases (mtaB, mttB), but only a few sequences phylogenetically cluster with methylotrophic methanogens. Our results suggest that the microbial methane in the Guaymas subsurface was produced over geologic time by relatively small methanogen populations, which have been variably influenced by thermal sediment alteration. Higher resolution metagenomic sampling may clarify the modern methanogen community. This study highlights the importance of using a multidisciplinary approach to capture microbial influences in dynamic, deep subsurface settings like Guaymas Basin.

Complete Genome Sequence of Methanofollis aquaemaris BCRC 16166 T , Isolated from a Marine Aquaculture Fishpond

The hydrogenotrophic methanogen Methanofollis aquaemaris BCRC 16166^T (= N2F9704^T = DSM 14661^T) was isolated from a marine aquaculture fishpond near Wang-gong (Taiwan, Republic of China). The genome of strain BCRC 16166^T was selected for sequencing in order to provide further information about the species delineation and its infected virus.

Methanofollis propanolicus sp. nov., a novel archaeal isolate from a Costa Rican oil well that uses propanol for methane production

A novel methanogenic strain, CaP3V-MF-L2A^T, was isolated from an exploratory oil well from Cahuita National Park, Costa Rica. The cells were irregular cocci, 0.8–1.8 μm in diameter, stained Gram-negative and were motile. The strain utilized H₂/CO₂, formate and the primary and secondary alcohols 1-propanol and 2-propanol for methanogenesis, but not acetate, methanol, ethanol, 1-butanol or 2-butanol. Acetate was required as carbon source. The novel isolate grew at 25–40 °C, pH 6.0–7.5 and 0–2.5% (w/v) NaCl. 16S rRNA gene sequence analysis revealed that the strain is affiliated to the genus Methanofollis. It shows 98.8% sequence similarity to its closest relative Methanofollis ethanolicus. The G + C content is 60.1 mol%. Based on the data presented here type strain CaP3V-MF-L2A^T (= DSM 113321^T = JCM 39176^T) represents a novel species, Methanofollis propanolicus sp. nov.

Complete Genome Sequence of Methanofollis formosanus DSM 15483T, Isolated from an Aquaculture Fish Pond

The hydrogenotrophic strain Methanofollis formosanus DSM 15483T (= ML15T = OCM 798T) was isolated from an aquaculture fish pond near Wang-gong, Taiwan. The genome of strain DSM 15483T was selected for sequencing in order to provide further information about the species delineation and its unique habitat.