Erythrobacter rubeus sp. nov., a carotenoid-producing alphaproteobacterium isolated from coastal seawater

Alteromonas gilva sp. nov. and Erythrobacter fulvus sp. nov., isolated from a tidal mudflat

Strains chi3T and sf7T were collected from a tidal mudflat around Dongmak beach in Ganghwa, Republic of Korea. Both strains were Gram-stain-negative, aerobic or facultatively anaerobic, and rod-shaped. Results of phylogenetic tree analysis based on 16S rRNA and whole-genome sequences suggested that strains chi3T and sf7T belong to the genera Alteromonas and Erythrobacter, respectively. The cells of strain chi3T were non-motile and grew at 15-45 °C (optimum, 38 °C), at pH 6.0-10.0 (optimum, pH 8.0) and in the presence of 0-9.0 % (w/v) NaCl (optimum, 2.0 %). The cells of strain sf7T were motile as they had flagella and grew at 20-48 °C (optimum, 38 °C), at pH 6.0-10.0 (optimum, pH 9.0) and in the presence of 0-5.0 % (w/v) NaCl (optimum, 1.0 %). Strains chi3T and sf7T have average nucleotide identity values (70.0-70.4% and 78.9-81.7 %) and digital DNA-DNA hybridization values (21.8-22.3% and 21.0-25.6 %) with reference strains in the genera Alteromonas and Erythrobacter, respectively. Data from digital DNA-DNA hybridization, as well as phylogenetic, biochemical and physiological analyses, indicated the distinction of the two strains from the genera Alteromonas and Erythrobacter, respectively, and we thus propose the names Alteromonas gilva sp. nov. (type strain chi3T=KACC 22866T=TBRC 16612T) and Erythrobacter fulvus sp. nov. (type strain sf7T=KACC 22865T=TBRC 16611T).

Microalgae, Seaweeds and Aquatic Bacteria, Archaea, and Yeasts: Sources of Carotenoids with Potential Antioxidant and Anti-Inflammatory Health-Promoting Actions in the Sustainability Era

Carotenoids are a large group of health-promoting compounds used in many industrial sectors, such as foods, feeds, pharmaceuticals, cosmetics, nutraceuticals, and colorants. Considering the global population growth and environmental challenges, it is essential to find new sustainable sources of carotenoids beyond those obtained from agriculture. This review focuses on the potential use of marine archaea, bacteria, algae, and yeast as biological factories of carotenoids. A wide variety of carotenoids, including novel ones, were identified in these organisms. The role of carotenoids in marine organisms and their potential health-promoting actions have also been discussed. Marine organisms have a great capacity to synthesize a wide variety of carotenoids, which can be obtained in a renewable manner without depleting natural resources. Thus, it is concluded that they represent a key sustainable source of carotenoids that could help Europe achieve its Green Deal and Recovery Plan. Additionally, the lack of standards, clinical studies, and toxicity analysis reduces the use of marine organisms as sources of traditional and novel carotenoids. Therefore, further research on the processing of marine organisms, the biosynthetic pathways, extraction procedures, and examination of their content is needed to increase carotenoid productivity, document their safety, and decrease costs for their industrial implementation.

Winogradskyella luteola sp.nov., Erythrobacter ani sp. nov., and Erythrobacter crassostrea sp.nov., isolated from the hemolymph of the Pacific Oyster Crassostrea gigas

Three new bacterial strains, WHY3^T, WH131^T, and WH158^T, were isolated and described from the hemolymph of the Pacific oyster Crassostrea gigas utilizing polyphasic taxonomic techniques. The 16S rRNA gene sequence analysis revealed that strain WHY3^T was a member of the genus Winogradskyella, whereas strains WHI31^T and WH158^T were members of the genus Erythrobacter. According to the polygenomic study the three strains formed individual lineages with strong bootstrap support. The comparison of dDDH-and ANI values, percentage of conserved proteins (POCP), and average amino acid identity (AAl) between the three strains and their relatives established that the three strains represented two separate genera. Menaquinone-6 was reported as the major respiratory quinone in strain WHY3^T and Ubiquinone-10 for strains WH131^T and WH158^T, respectively. The major cellular fatty acids for strain WHY3^T were C_15:0, anteiso-C_15:1 ω7c, iso-C_15:0, C_16:1ω7c. The major cellular fatty acids for strains WH131^T and WH158^T were C_14:02-OH and t_18:1ω12 for WH131^T and C_17:0, and C_18:1ω7c for strain WH158^T. Positive Sudan Black B staining Indicated the presence of polyhydroxyalkanoic acid granules for strains WH131^T and WH158^T but not for strain WHY3^T. The DNA G + C contents of strains WHY3^T, WH131^T and WH158^T were 34.4, 59.7 and 56.6%, respectively. Gene clusters predicted some important genes involved in the bioremediation process. Due to the accomplishment of polyphasic taxonomy, we propose three novel species Winogradskyella luteola sp.nov. (type strain WHY3^T = DSM 111804^T = NCCB 100833^T), Erythrobacter ani sp.nov. (WH131^T = DSM 112099^T = NCCB 100824^T) and Erythrobacter crassostrea sp.nov. (WH158^T = DSM 112102^T = NCCB 100877^T).