Marinicellulosiphila megalodicopiae gen. nov., sp. nov., a deep-sea alkaliphilic cellulolytic bacterium isolated from an endemic ascidian Megalodicopia hians

The strain TOYAMA8T is a deep-sea alkaliphilic cellulolytic bacterium isolated from a slurry-adhered epiphytic site of Megalodicopia hians. Cells of this strain are Gram-negative, aerobic, curved rods or spirilla, motile with monopolar flagella, and grow on cellulose as the sole carbon source. Compared to other closely related species, this bacterium is characterized by a large number of cellulase genes. Strain TOYAMA8T showed alkaliphilic growth within the pH range 7.5-9.0. The major cellular fatty acids were C18 : 1 ω7, C14 : 0, C16 : 0 and C16 : 1 ω7. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipids and aminolipids. A major respiratory lipoquinone was Q-9. Phylogenomic analysis using the 16S rRNA gene and whole-genome sequence data showed that the strain is related to the families Gynuellaceae, Saccharospirillaceae and Natronospirillaceae. The values of 16S rRNA gene sequence similarity, amino acid identity and percentage of conserved proteins between the strain TOYAMA8T and related species were low, with maximum values of 90.6, 48.1 and 34.6%, respectively. These results, together with differences in phenotypic and biochemical characteristics, indicate that the new isolate TOYAMA8T represents a novel genus and species, for which the name Marinicellulosiphila megalodicopiae gen. nov., sp. nov., is proposed. The type strain is TOYAMA8T (JCM 31119T=DSM 114864T).

Microbial community of soda Lake Van as obtained from direct and enriched water, sediment and fish samples

Soda lakes are saline and alkaline ecosystems that are considered to have existed since the first geological records of the world. These lakes support the growth of ecologically and economically important microorganisms due to their unique geochemistry. Microbiota members of lakes are valuable models to study the link between community structure and abiotic parameters such as pH and salinity. Lake Van is the largest endroheic lake and in this study, bacterial diversity of lake water, sediment, and pearl mullet (inci kefali; Alburnus tarichi), an endemic species of fish which are collected from different points of the lake, are studied directly and investigated meticulously using a metabarcoding approach after pre-enrichment. Bacterial community structures were identified using Next Generation Sequencing of the 16S rRNA gene. The analysis revealed that the samples of Lake Van contain high level of bacterial diversity. Direct water samples were dominated by Proteobacteria, Cyanobacteria, and Bacteroidota, on the other hand, pre-enriched water samples were dominated by Proteobacteria and Firmicutes at phylum-level. In direct sediment samples Proteobacteria, whereas in pre-enriched sediment samples Firmicutes and Proteobacteria were determined at highest level. Pre-enriched fish samples were dominated by Proteobacteria and Firmicutes at phylum-level. In this study, microbiota members of Lake Van were identified by taxonomic analysis.

Impacts of microplastics exposure on mussel (Mytilus edulis) gut microbiota

Microplastics (MPs), plastics with particles smaller than 5 mm, have been found almost in every corner of the world, especially in the ocean. Due to the small size, MPs can be ingested by animals and enter the marine trophic chain. MPs can affect animal health by physically causing damage to the digestive tract, leaking plastic chemical components, and carrying environmental pollutants and pathogens into animals. In this study, impacts of MPs ingestion on gut microbiota were investigated. Filter feeding mussels were exposed to "virgin" and "weathered" MPs at relatively realistic concentration 0.2 mg L^-1 ("low") and exaggerated concentration 20 mg L^-1 ("high") for 6 weeks. Influence in mussel gut microbiota was investigated with 16S rRNA gene high-throughput sequencing. As compared with non-exposed mussels, alteration of gut microbiota was observed after mussels were exposed to MPs for 1 week, 3 weeks, 6 weeks, and even after 8-day post-exposure depuration. Potential human pathogens were found among operational taxonomic units (OTUs) with increased abundance induced by MP-exposure. Faecal pellets containing microorganisms from altered gut microbiota and MPs might further influence microbiota of surrounding environment. Our results have demonstrated impacts of MP-exposure on mussel gut microbiota and suggested possible consequent effects on food quality, food safety, and the well-being of marine food web in the ecosystem for future studies.

Salinibius halmophilus gen. nov., sp. nov., isolated from a marine solar saltern

A novel Gram-stain-negative, facultatively anaerobic, flagellated and spiral-shaped bacterium, designated WDS2A16AT was isolated from a marine solar saltern in Weihai, PR China. Growth was observed at 20–40 °C (optimal 33–37 °C), 1–15 % (w/v) NaCl (optimal 3–4 %) and pH 6.0–9.0 (optimal pH 7.5). Major cellular fatty acids (>10 %) were C18 : 1ω7c and C16 : 0. Phosphatidylglycerol, diphosphatidylglycerol and an unidentified glycolipid were detected as the predominant polar lipids. The sole respiratory quinone was Q-8. The DNA G+C content of strain WDS2A16AT was 48.5 mol%. The 16S rRNA gene sequence similarities of WDS2A16AT with other species were less than 91 %. The average nucleotide identity, in silico DNA–DNA hybridization and amino acid identity of strain WDS2A16AT with the most related strain Gynuella sunshinyii YC6258 T were 66.1, 19.3 and 48.1 %, respectively. Comparative analysis of 16S rRNA gene sequences and phenotypic characterization indicated that strain WDS2A16AT represents a novel species in a new genus, for which the name Salinibius halmophilus gen. nov., sp. nov. is proposed. The type strain is WDS2A16AT (=KCTC 52225T=MCCC 1H00139T).

Characteristics of phenol degradation in saline conditions of a halophilic strain JS3 isolated from industrial activated sludge

Several halophilic bacteria have been reported to degrade phenol. However, there are a few works about salt-tolerant fungi which can utilize phenol as sole source of carbon. In this study, a halophilic strain JS3 which could degrade phenol with high efficiency was separated and identified. The effect of initial phenol concentration on phenol biodegradation was investigated and optimal pH, temperature, as well as salt-tolerance were evaluated. The isolate could degrade less than 800 mg/L phenol completely in 72 h. It grew well when pH, temperature, and salinity were at values of 4.0-9.0, 30-40°C, and 0-7%, respectively. The optimal pH, temperature and salinity were 6.0, 35°C and 0%. More than 99% of 500 mg/L phenol was degraded in the optimal condition within 24h. The tolerance of wide range of pH, temperature and salinity indicated that strain JS3 was effective for phenol removal in hypersaline wastewaters.