Inhibition of Methylmercury and Methane Formation by Nitrous Oxide in Arctic Tundra Soil Microcosms

Zhang, Lijie; Yin, Yongchao; Sun, Yanchen; Liang, Xujun; Graham, David E.; Pierce, Eric M.; Löffler, Frank E.; Gu, Baohua

doi:10.1021/acs.est.2c09457

Cited by 11 publications

(4 citation statements)

References 85 publications

(194 reference statements)

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“…The V4 region of the 16S rRNA gene was polymerase chain reaction (PCR) amplified from each sample using barcoded versions of the primers 515FY and 806RB ( 58 – 60 ). Each 50 µL PCR reaction contained 10 µL GoTaq 5× Flexi buffer, 5 µL of 25 mM MgCl 2 , 1 µL 10 mM deoxynucleotide triphosphates (dNTPs), 0.5 µL GoTaq Flexi DNA polymerase (Promega, WI, USA), 29.5 µL sterile water, 1 µL each of 10 µM forward and reverse primers, and 2 µL of extracted DNA.…”

Section: Methodsmentioning

confidence: 99%

Distinct microbial communities degrade cellulose diacetate bioplastics in the coastal ocean

Sun,

Mazzotta,

Miller

et al. 2023

Appl Environ Microbiol

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Cellulose diacetate (CDA) is a bio-based plastic widely used in consumer products. CDA is a promising alternative to conventional thermoplastics due to its susceptibility to biodegradation in various environments. Despite widespread evidence for the degradation of CDA, relatively little is known about the microorganisms that drive degradation, particularly in the ocean. Recently, we documented the biodegradation of CDA-based materials (i.e., fabric, film, and foam) in a continuous-flow natural seawater mesocosm on the timescales of months, as indicated by mass loss, enzyme activity, and respiration to carbon dioxide. These findings paved the way for the present study aimed at identifying key microbial taxa implicated in CDA degradation. Analysis based on 16S rRNA gene amplicon sequencing of bacteria and archaea revealed that material type, incubation time, material morphology (e.g., fabric vs film), and plasticizer content significantly influenced the microbial community structure. Differential abundance analysis revealed that bacterial taxa affiliated with the families of Arenicellaceae , Cellvibrionaceae , Methyloligellaceae , Micavibrionaceae , Puniceicoccaceae , Spirosomaceae , and Thermoanaerobaculaceae , and the order of Pseudomonadales potentially initiated the degradation (i.e., deacetylation) of CDA fabric and film. These taxa were notably distinct from CDA-degrading microbes reported in non-seawater environments. Collectively, the findings lend further support for CDA as a promising next-generation, high-utility, and low-environmental persistence bioplastic material. IMPORTANCE Cellulose diacetate (CDA) is a promising alternative to conventional plastics due to its versatility in manufacturing and low environmental persistence. Previously, our group demonstrated that CDA is susceptible to biodegradation in the ocean on timescales of months. In this study, we report the composition of microorganisms driving CDA degradation in the coastal ocean. We found that the coastal ocean harbors distinct bacterial taxa implicated in CDA degradation and these taxa have not been previously identified in prior CDA degradation studies, indicating an unexplored diversity of CDA-degrading bacteria in the ocean. Moreover, the shape of the plastic article (e.g., a fabric, film, or foam) and plasticizer in the plastic matrix selected for different microbial communities. Our findings pave the way for future studies to identify the specific species and enzymes that drive CDA degradation in the marine environment, ultimately yielding a more predictive understanding of CDA biodegradation across space and time.

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Section: Methodsmentioning

confidence: 99%

Distinct microbial communities degrade cellulose diacetate bioplastics in the coastal ocean

Sun,

Mazzotta,

Miller

et al. 2023

Appl Environ Microbiol

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“…A possible explanation for the delayed start of N 2 O consumption is the inhibition of corrinoid-dependent pathways. Micromolar concentrations of N 2 O were shown to repress methionine biosynthesis [ 67 ], methanogenesis [ 86 ], methylmercury formation [ 87 ], and bacterial reductive dechlorination [ 32 ], all processes that involve enzymatic steps that strictly depend on the cobalt (I) supernucleophile, a species highly susceptible to oxidation by N 2 O [ 88 ]. An initial N 2 O concentration of 2 mM exceeds the reported inhibitory constants for corrinoid-dependent enzymes about 100-fold, suggesting the disruption of metabolic pathways directly or indirectly impacted N 2 O-consuming populations.…”

Section: Discussionmentioning

confidence: 99%

pH selects for distinct N2O-reducing microbiomes in tropical soil microcosms

Sun,

Yin,

et al. 2024

ISME Communications

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Nitrous oxide (N2O), a greenhouse gas with ozone destruction potential, is mitigated by the microbial reduction to dinitrogen catalyzed by N2O reductase (NosZ). Bacteria with NosZ activity have been studied at circumneutral pH but the microbiology of low pH N2O reduction has remained elusive. Acidic (pH < 5) tropical forest soils were collected in the Luquillo Experimental Forest in Puerto Rico, and microcosms maintained with low (0.02 mM) and high (2 mM) N2O assessed N2O reduction at pH 4.5 and 7.3. All microcosms consumed N2O, with lag times of up to 7 months observed in microcosms with 2 mM N2O. Comparative metagenome analysis revealed that Rhodocyclaceae dominated in circumneutral microcosms under both N2O feeding regimes. In pH 4.5 microcosms, Peptococcaceae dominated in high-N2O, and Hyphomicrobiaceae in low-N2O microcosms. Seventeen high-quality metagenome-assembled genomes (MAGs) recovered from the N2O-reducing microcosms harbored nos operons, with all eight MAGs derived from acidic microcosms carrying the clade II type nosZ and lacking nitrite reductase genes (nirS/K). Five of the 8 MAGs recovered from pH 4.5 microcosms represent novel taxa indicating an unexplored N2O-reducing diversity exists in acidic tropical soils. A survey of pH 3.5–5.7 soil metagenome datasets revealed that nosZ genes commonly occur, suggesting broad distribution of N2O reduction potential in acidic soils.

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“…A possible explanation for the delayed start of N 2 O consumption is the inhibition of corrinoid-dependent pathways. Micromolar concentrations of N 2 O were shown to repress methionine biosynthesis [64], methanogenesis [83], methylmercury formation [84], and bacterial reductive dechlorination [32], all processes that involve enzymatic steps that strictly depend on the cobalt (I) supernucleophile, a species highly susceptible to oxidation by N 2 O [85]. An initial N 2 O concentration of 2 mM exceeds the reported inhibitory constants for corrinoid-dependent enzymes about 100-fold, suggesting the disruption of metabolic pathways directly or indirectly impacted N 2 O-consuming populations.…”

Section: Discussionmentioning

confidence: 99%

pH selects for distinct N₂O-reducing microbiomes in tropical soil microcosms

Sun,

Yin,

et al. 2023

Preprint

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Nitrous oxide (N2O), a greenhouse gas with ozone destruction potential, is mitigated by the microbial reduction to dinitrogen catalyzed by N2O reductase (NosZ). Bacteria with NosZ activity have been studied at circumneutral pH but the microbiology of low pH N2O reduction has remained elusive. Acidic (pH<5) tropical forest soils were collected in the Luquillo Experimental Forest in Puerto Rico, and microcosms maintained with low (0.02mM) and high (2mM) N2O assessed N2O reduction at pH 4.5 and 7.3. All microcosms consumed N2O, but long lag times of up to 7 months were observed in microcosms with 2 mM N2O. Comparative metagenome analysis revealed thatRhodocyclaceaedominated in circumneutral microcosms under both N2O feeding regimes. In acidic microcosms,Peptococcaceaedominated in high-N2O, andHyphomicrobiaceaein low-N2O microcosms. Seventeen metagenome-assembled genomes (MAGs) recovered from these microcosms harborednosoperons, with all eight MAGs derived from acidic microcosms carrying the clade II typenosZ, lacking nitrite reductase genes (nirS,nirK). Five of these MAGs represented novel taxa indicating an unexplored N2O-reducing diversity exists in acidic tropical soils. A survey of pH 3.5-5.7 soil metagenome datasets revealed thatnosZgenes commonly occur, suggesting broad distribution of N2O reduction potential in acidic soils.

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Inhibition of Methylmercury and Methane Formation by Nitrous Oxide in Arctic Tundra Soil Microcosms

Cited by 11 publications

References 85 publications

Distinct microbial communities degrade cellulose diacetate bioplastics in the coastal ocean

Distinct microbial communities degrade cellulose diacetate bioplastics in the coastal ocean

pH selects for distinct N2O-reducing microbiomes in tropical soil microcosms

pH selects for distinct N₂O-reducing microbiomes in tropical soil microcosms

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