Aquaticitalea lipolytica gen. nov., sp. nov., isolated from Antarctic seawater

Parerythrobacter lacustris sp. nov., a novel member of the family Erythrobacteraceae isolated from an inland alpine lake

A novel bacterium, designated as strain RS5-5T, was isolated from lake water in northwestern China. Cells of the isolate were observed to be rod shaped and Gram stain negative. Its growth occurred at 4-37 ℃, pH 6.5-9.0 and in the presence of 0-5% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain RS5-5T was most closely related to Qipengyuania sediminis GDMCC 1.2497T (97.5%), followed by Erythrobacter dokdonensis DSW-74T (97.3%) and Qipengyuania algicida GDMCC 1.2535T (97.0%). Phylogenomic analysis revealed that strain RS5-5T formed a distinct branch with the genus Parerythrobacter. The sole quinone was ubiquinone-10, and the major fatty acids (≥ 10%) were unsaturated fatty acids including C17:1 ω6c, summed feature 3 (C16:1 ω7c/C16:1 ω6c) and summed feature 8 (C18:1 ω7c/C18:1 ω6c). The polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, one unidentified sphingoglycolipid, three unidentified glycolipids, one unidentified aminoglycolipid, one unidentified aminolipid, two unidentified phospholipids and four unidentified polar lipids. Chemotaxonomic characteristics of strain RS5-5T were coincident with those of the genus Parerythrobacter members. The average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values between strain RS5-5T and two Parerythrobacter reference strains were in the ranges of 73.2-77.7%, 69.0-78.0% and 18.9-20.4%, respectively. The genomic DNA G + C content of strain RS5-5T was 64.1%. The results of phenotypic, phylogenetic and genomic analyses suggested that strain RS5-5T represents a novel species in the genus Parerythrobacter, for which the name Parerythrobacter lacustris sp. nov. is proposed. The type strain is RS5-5T (= GDMCC 1.3163T = KCTC 92277T).

Sandaracinobacteroides sayramensis sp. nov., a yellow-pigmented bacterium isolated from lake water

A Gram-negative, non-motile, facultatively anaerobic, rod-shaped bacterium, designated strain RS1-74^T, was isolated from the surface water of Sayram Lake, Xinjiang Uygur Autonomous Region, China. The strain was able to grow optimally at 30 °C and pH 7.0-7.5, and in the presence of 0-0.5 % (v/w) NaCl. Catalase and oxidase activities were present. H₂S was produced. Chemotaxonomic analysis showed Q-10 was the sole respiratory quinone. The polar lipids were composed of phosphatidylethanolamine, diphosphatidylglycerol, two glycolipids, phosphatidylglycerol, sphingoglycolipid and two unidentified lipids. Summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c) and summed feature 8 (C_18 : 1  ω7c and/or C_18 : 1  ω6c) were the predominant fatty acids. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain RS1-74^T was closely related to 'Sandaracinobacter neustonicus' JCM 30 734 (98.65 %), 'Sandaracinobacter sibiricus' RB16-17 (98.42 %) and Sandaracinobacteroides hominis SZY PN-1^T (97.09%). The genomic DNA G+C content was 66.45 mol%. The average nucleotide identity and DNA-DNA hybridization values among the genomes of strain RS1-74^T and 'Sandaracinobacter neustonicus' JCM 30734 and Sandaracinobacteroides hominis SZY PN-1^T were 78.2 and 77.22 %, and 22.2 and 20.40 %, respectively. Based on the physiological, biochemical, phylogenetic and genomic data, strain RS1-74^T represents a novel species within the genus Sandaracinobacteroides, for which the name Sandaracinobacteroides sayramensis sp. nov. is proposed, with type strain RS1-74^T (=KCTC 82674^T=MCCC 1K06282^T).

Bacterial Carotenoids: Extraction, Characterization, and Applications

Natural carotenoids are secondary metabolites that exhibit antioxidant, anti-inflammatory, and anti-cancer properties. These types of compounds are highly demanded by pharmaceutical, cosmetic, nutraceutical, and food industries, leading to the search for new natural sources of carotenoids. In recent years, the production of carotenoids from bacteria has become of great interest for industrial applications. In addition to carotenoids with C40-skeletons, some bacteria have the ability to synthesize characteristic carotenoids with C30-skeletons. In this regard, a great variety of methodologies for the extraction and identification of bacterial carotenoids has been reported and this is the first review that condenses most of this information. To understand the diversity of carotenoids from bacteria, we present their biosynthetic origin in order to focus on the methodologies employed in their extraction and characterization. Special emphasis has been made on high-performance liquid chromatography-mass spectrometry (HPLC-MS) for the analysis and identification of bacterial carotenoids. We end up this review showing their potential commercial use. This review is proposed as a guide for the identification of these metabolites, which are frequently reported in new bacteria strains.

Different co-occurring bacteria enhance or decrease the growth of the microalga Nannochloropsis sp. CCAP211/78

Marine photosynthetic microalgae are ubiquitously associated with bacteria in nature. However, the influence of these bacteria on algal cultures in bioreactors is still largely unknown. In this study, eighteen different bacterial strains were isolated from cultures of Nannochloropsis sp. CCAP211/78 in two outdoor pilot-scale tubular photobioreactors. The majority of isolates was affiliated with the classes Alphaproteobacteria and Flavobacteriia. To assess the impact of the eighteen strains on the growth of Nannochloropsis sp. CCAP211/78, 24-well plates coupled with custom-made LED boxes were used to simultaneously compare replicate axenic microalgal cultures with addition of individual bacterial isolates. Co-culturing of Nannochloropsis sp. CCAP211/78 with these strains demonstrated distinct responses, which shows that the technique we developed is an efficient method for screening the influence of harmful/beneficial bacteria. Two of the tested strains, namely a strain of Maritalea porphyrae (DMSP31) and a Labrenzia aggregata strain (YP26), significantly enhanced microalgal growth with a 14% and 12% increase of the chlorophyll concentration, respectively, whereas flavobacterial strain YP206 greatly inhibited the growth of the microalga with 28% reduction of the chlorophyll concentration. Our study suggests that algal production systems represent a 'natural' source to isolate and study microorganisms that can either benefit or harm algal cultures.

Pseudobizionia ponticola gen. nov., sp. nov., isolated from seawater

A Gram-stain-negative, aerobic, non-motile and ovoid or rod-shaped bacterial strain, designated MM-14^T, was isolated from seawater sampled from the Yellow Sea in the Republic of Korea and its taxonomic position was investigated using a polyphasic approach. Strain MM-14^T grew optimally at 30 °C and in the presence of approximately 2.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain MM-14^T clustered with the type strain of Hanstruepera neustonica. The novel strain exhibited a 16S rRNA gene sequence similarity value of 96.06 % to the type strain of H. neustonica, but higher 16S rRNA gene sequence similarity values (96.13-96.69 %) to the type strains of Bizionia echini, Bizionia hallyeonensis and Bizionia psychrotolerans. Strain MM-14^T contained MK-6 as the predominant menaquinone and iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH as the major fatty acids. The major polar lipids were phosphatidylethanolamine, one unidentified lipid and one unidentified aminolipid. The DNA G+C content of strain MM-14^T was 34.6 mol%. The phylogenetic and chemotaxonomic data and other phenotypic properties revealed that strain MM-14^T constitutes a new genus and species within the family Flavobacteriaceae of the phylum Bacteroidetes, for which the name Pseudobizionia ponticola gen. nov., sp. nov. is proposed. The type strain of Pseudobizionia ponticola is MM-14^T (=KACC 19434^T=KCTC 62139^T=NBRC 113019^T).