Aestuariirhabdus litorea gen. nov., sp. nov., isolated from a sea tidal flat and proposal of Aestuariirhabdaceae fam. nov

Simultaneous treatment of epichlorohydrin wastewater and polyhydroxyalkanoate recovery by halophilic aerobic granular sludge highly enriched by Halomonas sp

The treatment of epichlorohydrin (ECH) wastewater exists chances for achieving cleaner production. This study initially employed moderately halophilic aerobic granular sludge (HAGS) to treat ECH wastewater, and the resulting HAGS was utilized to recover polyhydroxyalkanoate (PHA). During the acclimation process of HAGS, the chemical oxygen demand removal efficiency stabilized at 70 %. Moreover, due to the high enrichment of Halomonas sp. (relative abundance of 86 ± 0.50 %), the maximum PHA content of wasted HAGS was 52.67 wt% in the fermentation process. Simultaneously, the utilization of nuclear magnetic resonance spectroscopy (1H and 13C spectra) and fourier transform infrared spectroscopy for the structural analysis of polymers revealed that polyhydroxybutyrate was the predominant substance extracted from HAGS. In this study, the innovative use of highly enriched HAGS for treating ECH wastewater and simultaneously recovering PHA not only enables the efficient biological treatment of ECH wastewater but also realizes resource recovery of ECH wastewater.

Aestuariirhabdus haliotis sp. nov., isolated from abalone viscera and emended description of the genus Aestuariirhabdus

Two novel strains, Z083T and Z084, were isolated from the viscera of abalone, Haliotis discus hannai, sampled in Weihai, PR China. The phenotypic, chemotaxonomic and genomic characteristics of the two strains were studied. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between the two strains were 99.8 and 98.9 %, respectively, suggesting that the two strains belonged to the same species. The 16S rRNA gene sequence analysis showed 99.8 % similarity between the two strains, while the genome analysis indicated that they were not from one clonal origin. Phylogenetic analysis of 16S rRNA gene sequences showed the two strains belonged to the genus Aestuariirhabdus and Aestuariirhabdus litorea JCM 32043T was the closest strain (97.5 %). Genomic analysis, including calculations of ANI, dDDH, amino acid identity (AAI) and percentage of conserved proteins (POCP), between Z083T, Z084 and A. litorea JCM 32043T clearly separated those two strains from A. litorea JCM 32043T as the values were below the thresholds for species delineation. The genome size of strains Z083T and Z084 were approximately 4.16 and 4.23 Mbp, respectively, and the DNA G+C contents of both strains were 51.8 mol%. According to the phenotypic, chemotaxonomic and phylogenetic characterizations and the results of genome analysis, Z083T and Z084 could be identified as belonging to a novel species of the genus Aestuariirhabdus , for which the name Aestuariirhabdus haliotis sp. nov., is proposed, with Z083T (=MCCC 1H00501T=KCTC 92006T) as the type strain.

Proposal of Zooshikellaceae fam. nov. to accommodate the genera Zooshikella and Spartinivicinus and reclassification of Zooshikella marina as a later heterotypic synonym of Zooshikella ganghwensis based on whole genome sequence analysis

The genus Spartinivicinus, affiliated to the class Gammaproteobacteria, is an important marine member that produces prodiginines. Currently, its taxonomic assignment to family level is not well presented. Phylogeny of 16S rRNA gene sequences indicated that Spartinivicinus forms a monophyletic clade with Zooshikella, which is neighboured by Aestuariirhabdus of the family Aestuariirhabdaceae and another monophyletic clade of the family Endozoicomonadaceae. The 16S rRNA gene of Spartinivicinus ruber S2-4-1H^T had sequence similarities to those of Aestuariirhabdus litorea GTF13^T, Zooshikella members and Endozoicomonas members of 93.4%, 93.2-93.4  and <92.5 %, respectively. Phylogenomic analysis based on 120 bacterial conserved single-copy genes highly supported placing Spartinivicinus as a sister member of Zooshikella, neighboured by Aestuariirhabdaceae and Endozoicomonadaceae members, indicating that Spartinivicinus and Zooshikella could be considered to belong to the same family. Thus, Zooshikellaceae fam. nov. is proposed to accommodate the two genera. Colonies of Spartinivicinus and Zooshikella are red-pigmented, which is different from Aestuariirhabdus (pale-yellow pigmented). The major respiratory quinone of S. ruber was ubiquinone (Q-9), similar to Zooshikella, but distinct from Aestuariirhabdus (Q-9 and Q-8). The predominant fatty acids and polar lipids of Spartinivicinus also showed a similar patterns to Zooshikella, but they were different from Aestuariirhabdus. Lastly, Spartinivicinus possessed a genome size of 6.68 Mbp and DNA G+C content of 40.1mol%, similar to Zooshikella, but much larger than Aestuariirhabdus. In addition, the 16S rRNA genes of Z. ganghwensis JC2044^T and Z. marina JC333^T possess sequence similarity of 99.79 %. Whole genome comparisons indicated that they shared 79.8 % digital DNA-DNA hybridization, 97.78 % average nucleotide identity and 97.31 % average amino acid identity values. Activities of catalase and oxidase for the two strains were positive. Hydrolysis of skimmed milk and Tweens (40, 60 and 80) was positive. Interestingly, the two strains produced different kinds of prodiginines. We propose that Z. marina is a later heterotypic synonym of Zooshikella ganghwensis.

Devosia aurantiaca sp. nov., Isolated from Mountain Soil and Proposal of Albitalea gen. nov. to Replace the Illegitimate Prokaryotic Genus Name Geomonas Khan et al. 2020

Strain H239^T, a gram-negative, strictly aerobic, and oxidase-positive, and catalase-negative bacterium, was isolated from mountain soil in Gangwon-do of South Korea. Colonies were orange colored, and cells were motile rods with a single polar flagellum. Growth was observed between 25 and 30 °C (optimum, 30 °C), between pH 7.0 and pH 9.0 (optimum, pH 7.5), and in the presence of 0-1.5% (w/v) NaCl (optimum 0.5-1%). Ubiquinone-10 was detected as the sole respiratory quinone. The major fatty acids (>10%) of strain H239^T were C_18:1 ω7c, C_18:0, and C_16:0. The polar lipids detected from strain H239^T consisted of two unidentified glycolipids, two unidentified phospholipids, and three unidentified polar lipids. The G+C content of strain H239^T based on its genome sequence was 62.0 mol%. Comparative 16S rRNA gene sequence analysis indicated that strain H239^T was most closely related to Devosia chinhatensis IPL18^T (97.7%), Devosia submarina KMM 9415^T (97.7%), and Devosia yakushimensis Yak96B^T (97.3%). Phylogenetic analyses based on the 16S rRNA gene and whole-genome sequences revealed that strain H239^T formed a distinct phyletic lineage as a new species within the genus Devosia. Based on its physiological, chemotaxonomic, and molecular properties, strain H239^T represents a novel species of the genus Devosia, for which the name Devosia aurantiaca sp. nov. is proposed. The type strain is H239^T (=KACC 21662^T=JCM 33930^T). In addition, because the prokaryotic genus name Geomonas Khan et al. 2020 is a later homonym of Geomonas Xu et al. 2020, the name is illegitimate (Principle 6 in the International Code of Nomenclature of Prokaryotes). Therefore, we propose to replace the problematic prokaryotic names Geomonas and Geomonas soli with Albitalea with Albitalea terrae, respectively.

Maritimibacter harenae sp. nov. and Sneathiella litorea sp. nov.: members of Alphaproteobacteria isolated from sea sand

Two Gram-negative, rod bacteria, strains DP07^T and DP05^T, showing catalase- and oxidase-positive activities, were isolated from sea sand in South Korea. Strain DP07^T was strictly aerobic and had a yellow colony colour. Contrastingly, strain DP05^T was facultatively aerobic and had a creamy colony colour. Both strains contained ubiquinone-10 as the sole isoprenoid quinone. Strain DP07^T contained cyclo-C_19:0 ω8c, C_16:0, summed feature 8 (comprising C_18:1 ω7c and/or C_18:1 ω6c), and C_16:0 2-OH as the major fatty acids and phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, and an unidentified polar lipid as the major polar lipids. Strain DP05^T contained C_16:0, cyclo-C_19:0, and summed feature 8 (comprising C_18:1 ω7c and/or C_18:1 ω6c) as the major fatty acids and phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminophospholipid, and two unidentified polar lipids as the major polar lipids. Cadaverine was detected as the predominant polyamine in both strains. The DNA G + C contents of strains DP07^T and DP05^T were 66.1 mol% and 51.8 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains DP07^T and DP05^T formed close phylogenetic lineages with Maritimibacter alkaliphilus HTCC2654^T (similarity, 98.1%) and Sneathiella chungangensis CAU 1294 ^T (similarity, 98.5%), respectively. The average nucleotide identity and DNA-DNA hybridisation values between strain DP07^T and M. alkaliphilus were 80.0% and 23.0%, respectively, and those between strain DP05^T and S. chungangensis were 77.1% and 19.9%, respectively. Based on the results of phenotypic, chemotaxonomic, and molecular analyses, strains DP07^T and DP05^T represent two novel species of the genera Maritimibacter and Sneathiella, respectively, for which we propose the following names: Maritimibacter harenae sp. nov. and Sneathiella litorea sp. nov. The type strains of M. harenae and S. litorea were DP07^T (= KACC 21429 ^T = JCM 33811 ^T) and DP05^T (= KACC 21431 ^T = JCM 33810 ^T), respectively.

Spartinivicinus ruber gen. nov., sp. nov., a Novel Marine Gammaproteobacterium Producing Heptylprodigiosin and Cycloheptylprodigiosin as Major Red Pigments

The red pigment prodiginines are identified as bacterial secondary metabolites and display a wide range of bioactive properties. Here, a novel rose-red pigmented bacterium, designated strain S2-4-1H^T, was isolated from coastal sediment of cordgrass Spartina alterniflora. Interestingly, it simultaneously produced heptylprodigiosin (C₂₂H₂₉N₃O) and cycloheptylprodigiosin (C₂₂H₂₇N₃O) as major red pigments, of which their chemical structures were established by liquid chromatography–mass spectrometry (LC–MS) and nuclear magnetic resonance (NMR). Bioactive assays revealed that both heptylprodigiosin and cycloheptylprodigiosin had antibacterial and antifungal activities, and notably, cycloheptylprodigiosin showed stronger bioactivity than heptylprodigiosin. The complete genome of strain S2-4-1H^T was determined to be 6,687,090 bp in length with a G + C content of 40.13 mol%, including a circular chromosome with a size of 6,361,125 bp and three plasmids with a size of 141,078, 102,423, and 82,464 bp, respectively. The biosynthetic gene cluster of two red pigments was predicted on a ∼41-kb gene fragment organized on the chromosome and displayed highly conserved features compared to several gammaproteobacterial species encoding the homologous genes. Finally, based on phenotypic, genotypic, and chemotaxonomic characteristics, strain S2-4-1H^T represented a novel genus-level species named Spartinivicinus ruber gen. nov., sp. nov. (type strain S2-4-1H^T = MCCC 1K03745^T = KCTC 72148^T). Our study provided a novel bacterial source and novel prodigiosin analogs as promising pharmaceuticals in biotechnological application.

Mucilaginibacter agri sp. nov. and Mucilaginibacter humi sp. nov., isolated from soil

Two Gram-stain-negative, facultative anaerobic and non-motile bacteria, strains R11T and S1162T, were isolated from soil in the Republic of Korea. Both strains were catalase- and oxidase-positive and contained menaquinone-7 as the major isoprenoid quinone. Strain R11T contained summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), iso-C15:0, C16:0 and iso-C17:0 3-OH as major fatty acids and phosphatidylethanolamine, an unidentified aminophospholipid and an unidentified aminolipid as major polar lipids; while strain S1162T contained summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), iso-C15:0, iso-C17:0 3-OH, C16:0 and summed feature 9 (10-methyl C16:0 and/or iso-C17:1 ω9c) as major fatty acids and phosphatidylethanolamine and an unidentified aminophospholipid as major polar lipids. The DNA G+C contents of strains R11T and S1162T calculated from their whole genomes were 42.7 and 42.9 mol%, respectively. Results of phylogenetic analysis based on 16S rRNA gene sequences showed that strain R11T formed a phylogenetic lineage with Mucilaginibacter jinjuensis YC7004T and strain S1162T formed a distinct phyletic lineage from closely related type strains within the genus Mucilaginibacter . Strains R11T and S1162T were most closely related to M. jinjuensis YC7004T and Mucilaginibacter panaciglaebae BXN5-31T with 97.78 and 97.23% 16S rRNA gene sequence similarities, respectively. On the basis of phenotypic, chemotaxonomic and molecular analysis, strains R11T and S1162T represent two novel species of the genus Mucilaginibacter , for which the names Mucilaginibacter agri sp. nov. and Mucilaginibacter humi sp. nov. are proposed, respectively. The type strains of M. agri and M. humi are R11T (=KACC 21228T=JCM 33472T) and S1162T (=KACC 21669T=JCM 33916T), respectively.