Dataset Information

Identification and Characterization of a Novel Salt-Tolerant Esterase from the Deep-Sea Sediment of the South China Sea.

ABSTRACT: Marine esterases play an important role in marine organic carbon degradation and cycling. Halotolerant esterases from the sea may have good potentials in industrial processes requiring high salts. Although a large number of marine esterases have been characterized, reports on halotolerant esterases are only a few. Here, a fosmid library containing 7,200 clones was constructed from a deep-sea sediment sample from the South China Sea. A gene H8 encoding an esterase was identified from this library by functional screening and expressed in Escherichia coli. Phylogenetic analysis showed that H8 is a new member of family V of bacterial lipolytic enzymes. H8 could effectively hydrolyze short-chain monoesters (C4-C10), with the highest activity toward p-nitrophenyl hexanoate. The optimal temperature and pH for H8 activity were 35°C and pH 10.0, respectively. H8 had high salt tolerance, remaining stable in 4.5 M NaCl, which suggests that H8 is well adapted to the marine saline environment and that H8 may have industrial potentials. Unlike reported halophilic/halotolerant enzymes with high acidic/basic residue ratios and low pI values, H8 contains a large number of basic residues, leading to its high basic/acidic residue ratio and high predicted pI (9.09). Moreover, more than 10 homologous sequences with similar basic/acidic residue ratios and predicted pI values were found in database, suggesting that H8 and its homologs represent a new group of halotolerant esterases. We also investigated the role of basic residues in H8 halotolerance by site-directed mutation. Mutation of Arg195, Arg203 or Arg236 to acidic Glu significantly decreased the activity and/or stability of H8 under high salts, suggesting that these basic residues play a role in the salt tolerance of H8. These results shed light on marine bacterial esterases and halotolerant enzymes.

SUBMITTER: Zhang Y

PROVIDER: S-EPMC5362591 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Publications

Identification and Characterization of a Novel Salt-Tolerant Esterase from the Deep-Sea Sediment of the South China Sea.

Zhang Yi Y Hao Jie J Zhang Yan-Qi YQ Chen Xiu-Lan XL Xie Bin-Bin BB Shi Mei M Zhou Bai-Cheng BC Zhang Yu-Zhong YZ Li Ping-Yi PY

Frontiers in microbiology 20170323

Marine esterases play an important role in marine organic carbon degradation and cycling. Halotolerant esterases from the sea may have good potentials in industrial processes requiring high salts. Although a large number of marine esterases have been characterized, reports on halotolerant esterases are only a few. Here, a fosmid library containing 7,200 clones was constructed from a deep-sea sediment sample from the South China Sea. A gene <i>H8</i> encoding an esterase was identified from this ...[more]

PMID: 28386249

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Project description:Chemoautotrophs within Campylobacterota, especially Sulfurovum and Sulfurimonas, are abundant in the seawater-sediment interface of the Formosa cold seep in the South China Sea. However, the in situ activity and function of Campylobacterota are unknown. In this study, the geochemical role of Campylobacterota in the Formosa cold seep was investigated with multiple means. Two members of Sulfurovum and Sulfurimonas were isolated for the first time from deep-sea cold seep. These isolates are new chemoautotrophic species that can use molecular hydrogen as an energy source and CO2 as a sole carbon source. Comparative genomics identified an important hydrogen-oxidizing cluster in Sulfurovum and Sulfurimonas. Metatranscriptomic analysis detected high expression of hydrogen-oxidizing gene in the RS, suggesting that H2 was likely an energy source in the cold seep. Genomic analysis indicated that the Sulfurovum and Sulfurimonas isolates possess a truncated sulfur-oxidizing system, and metatranscriptomic analysis revealed that Sulfurovum and Sulfurimonas with this genotype were active in the surface of RS and likely contributed to thiosulfate production. Furthermore, geochemical and in situ analyses revealed sharply decreased nitrate concentration in the sediment-water interface due to microbial consumption. Consistently, the denitrification genes of Sulfurimonas and Sulfurovum were highly expressed, suggesting an important contribution of these bacteria to nitrogen cycling. Overall, this study demonstrated that Campylobacterota played a significant role in the cycling of nitrogen and sulfur in a deep-sea cold seep. IMPORTANCE Chemoautotrophs within Campylobacterota, in particular Sulfurovum and Sulfurimonas, are ubiquitous in deep-sea cold seeps and hydrothermal vents. However, to date, no Sulfurovum or Sulfurimonas has been isolated from cold seeps, and the ecological roles of these bacteria in cold seeps remain to be investigated. In this study, we obtained two isolates of Sulfurovum and Sulfurimonas from Formosa cold seep, South China Sea. Comparative genomics, metatranscriptomics, geochemical analysis, and in situ experimental study indicated collectively that Campylobacterota played a significant part in nitrogen and sulfur cycling in cold seep and was the cause of thiosulfate accumulation and sharp reduction of nitrate level in the sediment-water interface. The findings of this study promoted our understanding of the in situ function and ecological role of deep-sea Campylobacterota.

Dataset Information

Identification and Characterization of a Novel Salt-Tolerant Esterase from the Deep-Sea Sediment of the South China Sea.

Publications

Identification and Characterization of a Novel Salt-Tolerant Esterase from the Deep-Sea Sediment of the South China Sea.

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