Oceanirhabdus sediminicola gen. nov., sp. nov., an anaerobic bacterium isolated from sea sediment

Reductive deiodination of 2,4,6-triiodophenol by Vallitalea sp. strain TIP-1 isolated from the marine sponge

An anaerobic microbial consortium capable of reductively dehalogenating 2,4,6-triiodophenol (2,4,6-TIP) was enriched from the marine sponge Hymeniacidon sinapium. The enrichment reductively deiodinated 100 μM of 2,4,6-TIP to 4-iodophenol (4-IP) and 2-iodophenol (2-IP) in the presence of sterile sponge tissue as the sole carbon source and electron donor. PCR-denaturing gradient gel electrophoresis and 16S rRNA gene sequence analysis revealed that bacteria closely related with Vallitalea guaymasensis and Oceanirhabdus sediminicola, both of which are members of the order Clostridiales, were predominant in the enrichment. When glucose was added to the enrichment as alternative carbon source, one of these bacteria grew predominantly, which was subsequently isolated as a pure culture. The strain, designated as TIP-1, showed 99.7% 16S rRNA gene sequence similarity with V. guaymasensis. In the presence of glucose, strain TIP-1 reductively deiodinated 2,4,6-TIP to 2-IP and 4-IP at a molar ratio of 3:1, during which 2,4-diiodophenol (2,4-DIP) and 2,6-diiodophenol (2,6-DIP) were observed as deiodinated intermediates. Glucose was required for 2,4,6-TIP deiodination, but 2,4,6-TIP was not essential for growth of strain TIP-1. The strain also deiodinated 2,4-DIP to 2-IP and 4-IP at a molar ratio of 1:1, and 2,6-DIP to 2-IP, but further deiodination of the monoiodophenols was not observed. These results suggest that strain TIP-1 removed both ortho- and para-substituted iodines equally. Such deiodinating bacteria could be applied to the mineralization or dehalogenation of triiodobenzene derivatives, which are widely used as X-ray contrast media.

Variation of Microbial Diversity in Catastrophic Oil Spill Area in Marine Ecosystem and Hydrocarbon Degradation of UCMs (Unresolved Complex Mixtures) by Marine Indigenous Bacteria

The study targeted an assessment of microbial diversity during oil spill in the marine ecosystem (Kaohsiung port, Taiwan) and screened dominant indigenous bacteria for oil degradation, as well as UCM weathering. DO was detected lower and TDS/conductivity was observed higher in oil-spilled area, compared to the control, where a significant correlation (R² = 1; P < 0.0001) was noticed between DO and TDS. The relative abundance (RA) of microbial taxa and diversities (> 90% similarity by NGS) were found higher in the boundary region of spilled-oily-water (site B) compared to the control (site C) and center of the oil spill area (site A) (B_RA/diversity > C_RA/diversity > A_RA/diversity). The isolated indigenous bacteria, such as Staphylococcus saprophyticus (CYCTW1), Staphylococcus saprophyticus (CYCTW2), and Bacillus megaterium (CYCTW3) degraded the C₁₀-C₃₀ including UCM of oil, where Bacillus sp. are exhibited more efficient, which are applicable for environmental cleanup of the oil spill area. Thus, the marine microbial diversity changes due to oil spill and the marine microbial community play an important role to biodegrade the oil, besides restoring the catastrophic disorders through changing their diversity by ecological selection and adaptation process.

Anaerophilus nitritogenes gen. nov., sp. nov., isolated from salt lake sediment in Xinjiang Province, China

An obligately anaerobic, nitrate-reducing bacterial strain (MJB2^T) was isolated from sediments of saline in Xinjiang province of China. Cells were Gram-stain-positive rods and motile by means of flagella and formed endospores. The novel strain MJB2^T was able to grow at 15-37 °C (optimum 28-30 °C), pH 5.8-9.4 (optimum 7.8) and with 1.0-7.0% NaCl (optimum 5.0-6.0%, w/v). Sulfate, sulfite, thiosulfate, elemental sulfur, nitrite and Fe(III) were not used as terminal electron acceptors. Oxidase and catalase reactions were positive. H₂S was producted from L-cystine. Complex substrates such as beef extract, peptone and yeast extract can be used as sole energy sources. The DNA G+C content was 29.4 mol%. The major cellular fatty acids (> 10%) were C_14:0, C_16:1 cis 7 and C_16:1 cis 9. The main polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, three unidentified amino lipids, one unidentified amino glycolipid, two unidentified glycolipid, one unidentified aminophospholipid and two unidentified lipids. No respiratory quinones were detected. According to phylogenetic analysis based on 16S rRNA gene sequences, strain MJB2^T was affiliated to the family Clostridiaceae (order Clostridiales) with highest 16S rRNA gene sequence similarity of 95.3% to Crassaminicella profunda Ra1766H^T. Strain MJB2^T exhibited 74.9% ANI values to C. profunda Ra1766H^T. In silico DNA-DNA relatedness value between strain MJB2^T and C. profunda Ra1766H^T was 19.5%. The distinct biochemical, chemotaxonomic and phylogenetic differences from the previously described taxa supported that strain MJB2^T represents a novel species of a new genus, for which the name Anaerophilus nitritogenes gen. nov., sp. nov. is proposed. The type strain is MJB2^T (=KCTC 15800^T=MCCC 1K03631^T).

Haloimpatiens lingqiaonensis gen. nov., sp. nov., an anaerobic bacterium isolated from paper-mill wastewater

An anaerobic bacterium, strain ZC-CMC3^T, was isolated from a wastewater sample in Zhejiang, China. Cells were Gram-stain-positive, peritrichous, non-spore-forming, rod-shaped (0.6-1.2 × 2.9-5.1 μm) and catalase- and oxidase-negative. Strain ZC-CMC3^T was able to grow at 25-48 °C (optimum 43 °C) and pH 5.5-8.0 (optimum pH 7.0). The NaCl concentration range for growth was 0-3 % (w/v) (optimum 0 %). The major polar lipids of the isolate were diphosphatidylglycerol, phosphatidylglycerol, several phospholipids and glycolipids. Main fermentation products from PYG medium were formate, acetate, lactate and ethanol. Substrates which could be utilized were peptone, tryptone, yeast extract and beef extract. No respiratory quinone was detected. The main fatty acids were C_14 : 0, C_16 : 0, C_16 : 1cis 7 and C_16 : 1cis 9. The DNA G+C content was 30.0 mol%. 16S rRNA gene sequence analysis revealed that the isolate belonged to the family Clostridiaceae. Phylogenetically, the most closely related species were Oceanirhabdus sediminicola NH-JN4^T (92.8 % 16S rRNA gene sequence similarity) and Clostridium tepidiprofundi SG 508^T (92.6 %). On the basis of phylogenetic, chemotaxonomic and phenotypic characteristics, strain ZC-CMC3^T represents a novel species of a new genus in the family Clostridiaceae, for which the name Haloimpatiens lingqiaonensis gen. nov., sp. nov. is proposed. The type strain of the type species is ZC-CMC3^T ( = KCTC 15321^T = JCM 19210^T = CCTCC AB 2013104^T).