Rice straw is a common agricultural waste. In order to increase the added value of rice straw and improve the performance of rice straw biochar. MgO-modified biochar (MRBC) was prepared from rice straw at different temperatures, pyrolysis time and MgCl2 concentrations. The microstructure, chemical and crystal structure were studied using X-ray diffraction (XRD), a Scanning Electron Microscope (SEM), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption desorption isotherms and Elementary Analysis (EA). The results showed that the pyrolysis temperature had significant influence on the structure and physicochemical property of MRBCs. MRBC-2 h has the richest microporous structure while MRBC-2 m has the richest mesoporous structure. The specific surface area (from 9.663 to 250.66 m2/g) and pore volume (from 0.042 to 0.158 cm3/g) of MRBCs increased as temperature rose from 300 to 600 °C. However, it was observed MgCl2 concentrations and pyrolysis time had no significant influence on pore structure of MRBCs. As pyrolysis temperature increased, pH increased and more oxygen-containing functional groups and mineral salts were formed, while MgO-modified yield, volatile matter, total content of hydrogen, oxygen, nitrogen, porosity and average pore diameter decreased. In addition, MRBCs formed at high temperature showed high C content with a low O/C and H/C ratios.

A Gram-stain-negative, non-spore-forming, motile, aerobic bacterium (strain C21T) was isolated from coral and identified using polyphasic identification approach. Global alignment of 16S rRNA gene sequences indicated that strain C21T shares 95.7 % sequence identity to its closest neighbour, Marinibactrum halimedae NBRC 110095T, followed by other type strains with identities of lower than 95 %. The average nucleotide identity and average amino acid identity values between strain C21T and M. halimedae NBRC 110095T were 69.6 and 64.8 %, respectively, indicating that strain C21T may represent a new species in a new genus. Phylogenetic analysis based on 16S rRNA gene and phylogenomic results indicated that strain C21T forms a distinct branch in the family Cellvibrionaceae . Cellular fatty acids and polar lipids could also readily distinguish strain C21T from closely related type strains. Therefore, strain C21T is suggested to represent a new species in a new genus, for which the name Sessilibacter corallicola gen. nov., sp. nov. is proposed. The type strain is C21T (=MCCC 1K03260T=KCTC 62317T).

Thermal stress is considered one of the main causes of mass scleractinian coral degradation; however, it is still unknown how corals can adapt to future global warming. In this study, ten genera of coral-associated flavobacteria were shown to produce zeaxanthin, a carotenoid antioxidant, which may help coral holobionts to alleviate thermal stress. In addition, a novel zeaxanthin-producing flavobacterium, designated R38T, was identified using polyphasic taxonomy. Although strain R38T shared a maximum 16S rRNA gene sequence similarity of 93% with Mesoflavibacter aestuarii KYW614T, phylogenetic analyses based on whole genome and 16S rRNA gene sequences revealed that strain R38T forms a distinct branch in a robust cluster composed of strain R38T and Leptobacterium flavescens KCTC 22160T under the family Flavobacteriaceae. Strain R38T exhibited average nucleotide identities of 70.2% and 72.5% for M. aestuarii KYW614T and L. flavescens KCTC 22160T, respectively. The only detected respiratory quinone was menaquinone 6 (MK-6). The genomic DNA G + C content was 33.2 mol%. The major polar lipids were phosphatidylmethylethanolamine, phosphatidylethanolamine, one unidentified ninhydrin phospholipid, three unidentified ninhydrin-positive lipids, and three unidentified lipids. The major cellular fatty acids were iso-C15 : 0, iso-C15 : 0ω6c, C16:2 DMA, and C13:1ω3c. The distinct biochemical, chemotaxonomic, phylogenetic, and phylogenomic differences from validly published taxa suggest that strain R38T represents a new species of a new genus, for which Prasinibacter corallicola gen. nov., sp. nov. is proposed. The type strain R38T (= MCCC 1K03889T = KCTC 72444T).

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