Three marine species of the genus Fulvivirga, rich sources of carbohydrate-active enzymes degrading alginate, chitin, laminarin, starch, and xylan

Advanced sustainable processes via functionalized Fe-N co-doped fishbone biochar for the remediation of plasticizer di-(2-ethylhexyl) phthalate-contaminated marine sediment

Sediments are important sinks for di-(2-ethylhexyl) phthalate (DEHP), a plasticizer, and thus, maintaining the sediment quality is essential for eliminating plasticizers in aqueous environments and recovering the sediment ecological functions. To mitigate the potential risks of endocrine-disrupting compounds, identifying an effective and eco-friendly degradation process of organic pollutants from sediments is important. However, sustainable and efficient utilization of slow pyrolysis for converting shark fishbone to generate shark fishbone biochar (SFBC) has rarely been explored. Herein, SFBC biomass was firstly produced by externally incorporating heteroatoms or iron oxide onto its surface in conjunction with peroxymonosulfate (PMS) to promote DEHP degradation and explore the associated benthic bacterial community composition from the sediment in the water column using the Fe-N-SFBC/PMS system. SFBC was pyrolyzed at 300-900 °C in aqueous sediment using a carbon-advanced oxidation process (CAOP) system based on PMS. SFBC was rationally modified via N or Fe-N doping as a radical precursor in the presence of PMS (1 × 10-5 M) for DEHP removal. The innovative SFBC/PMS, N-SFBC/PMS, and Fe-N-SFBC/PMS systems could remove 82%, 65%, and 90% of the DEHP at pH 3 in 60 min, respectively. The functionalized Fe3O4 and heteroatom (N) co-doped SFBC composite catalysts within a hydroxyapatite-based structure demonstrated the efficient action of PMS compared to pristine SFBC, which was attributed to its synergistic behavior, generating reactive radicals (SO4•-, HO•, and O2•-) and non-radicals (1O2) involved in DEHP decontamination. DEHP was significantly removed using the combined Fe-N-SFBC/PMS system, revealing that indigenous benthic microorganisms enhance their performance in DEHP-containing sediments. Further, DEHP-induced perturbation was particularly related to the Proteobacteria phylum, whereas Sulfurovum genus and Sulfurovum lithotrophicum species were observed. This study presents a sustainable method for practical, green marine sediment remediation via PMS-CAOP-induced processes using a novel Fe-N-SFBC composite material and biodegradation synergy.

Splendidivirga corallicola gen. nov., sp. nov. and Agaribacillus aureus gen. nov., sp. nov., two bacteria isolated from coral Porites lutea, and proposal of Splendidivirgaceae fam. nov

The Bacteroidota is one of the dominant bacterial phyla in corals. However, the exact taxa of those coral bacteria under the Bacteroidota are still unclear. Two aerobic, Gram-stain-negative, non-motile rods, designated strains BMA10T and BMA12T, were isolated from stony coral Porites lutea collected from Weizhou Island, PR China. Global alignment of 16S rRNA gene sequences indicated that both strains are closest to species of Fulvivirga with the highest identities being lower than 93 %, and the similarity value between these two strains was 92.3 %. Phylogenetic analysis based on 16S rRNA gene and genome sequences indicated that these two strains form an monophylogenetic lineage alongside the families Fulvivirgaceae, Reichenbachiellaceae, Roseivirgaceae, Marivirgaceae, Cyclobacteriaceae, and Cesiribacteraceae in the order Cytophagales, phylum Bacteroidota. The genomic DNA G+C contents of BMA10T and BMA12T were 38.4 and 41.9 mol%, respectively. The major polar lipids of BMA10T were phosphatidylethanolamine, unidentified aminophospholipid, four unidentified aminolipids, and five unidentified lipids. While those of BMA12T were phosphatidylethanolamine, two unidentified aminolipids, and five unidentified lipids. The major cellular fatty acids detected in both isolates were iso-C15 : 0 and C16 : 1  ω5c. Carbohydrate-active enzyme analysis indicated these two strains may utilize coral mucus or chitin. Based on above characteristics, these two strains are suggested to represent two new species in two new genera of a new family in the order Cytophagales, for which the name Splendidivirga corallicola gen. nov., sp. nov., Agaribacillus aureus gen. nov., sp. nov. and Splendidivirgaceae fam. nov. are proposed. The type strain of S. corallicola is BMA10T (=MCCC 1K08300T=KCTC 102045T), and that for A. aureus is BMA12T (=MCCC 1K08309T=KCTC 102046T).

Three novel marine species of the genus Reichenbachiella exhibiting degradation of complex polysaccharides

Three novel strains designated ABR2-5T, BKB1-1T, and WSW4-B4T belonging to the genus Reichenbachiella of the phylum Bacteroidota were isolated from algae and mud samples collected in the West Sea, Korea. All three strains were enriched for genes encoding up to 216 carbohydrate-active enzymes (CAZymes), which participate in the degradation of agar, alginate, carrageenan, laminarin, and starch. The 16S rRNA sequence similarities among the three novel isolates were 94.0%-94.7%, and against all three existing species in the genus Reichenbachiella they were 93.6%-97.2%. The genome sizes of the strains ABR2-5T, BKB1-1T, and WSW4-B4T were 5.5, 4.4, and 5.0 Mb, respectively, and the GC content ranged from 41.1%-42.0%. The average nucleotide identity and the digital DNA-DNA hybridization values of each novel strain within the isolates and all existing species in the genus Reichenbachiella were in a range of 69.2%-75.5% and 17.7-18.9%, respectively, supporting the creation of three new species. The three novel strains exhibited a distinctive fatty acid profile characterized by elevated levels of iso-C15:0 (37.7%-47.4%) and C16:1 ω5c (14.4%-22.9%). Specifically, strain ABR2-5T displayed an additional higher proportion of C16:0 (13.0%). The polar lipids were phosphatidylethanolamine, unidentified lipids, aminolipids, and glycolipids. Menaquinone-7 was identified as the respiratory quinone of the isolates. A comparative genome analysis was performed using the KEGG, RAST, antiSMASH, CRISPRCasFinder, dbCAN, and dbCAN-PUL servers and CRISPRcasIdentifier software. The results revealed that the isolates harbored many key genes involved in central metabolism for the synthesis of essential amino acids and vitamins, hydrolytic enzymes, carotenoid pigments, and antimicrobial compounds. The KEGG analysis showed that the three isolates possessed a complete pathway of dissimilatory nitrate reduction to ammonium (DNRA), which is involved in the conservation of bioavailable nitrogen within the ecosystem. Moreover, all the strains possessed genes that participated in the metabolism of heavy metals, including arsenic, copper, cobalt, ferrous, and manganese. All three isolated strains contain the class 2 type II subtype C1 CRISPR-Cas system in their genomes. The distinguished phenotypic, chemotaxonomic, and genomic characteristics led us to propose that the three strains represent three novel species in the genus Reichenbachiella: R. ulvae sp. nov. (ABR2-5T = KCTC 82990T = JCM 35839T), R. agarivorans sp. nov. (BKB1-1T = KCTC 82964T = JCM 35840T), and R. carrageenanivorans sp. nov. (WSW4-B4T = KCTC 82706T = JCM 35841T).