Aliidiomarina soli sp. nov., isolated from saline-alkaline soil

Viromic and Metagenomic Analyses of Commercial Spirulina Fermentations Reveal Remarkable Microbial Diversity

Commercially produced cyanobacteria preparations sold under the name spirulina are widely consumed, due to their traditional use as a nutrient-rich foodstuff and subsequent marketing as a superfood. Despite their popularity, the microbial composition of ponds used to cultivate these bacteria is understudied. A total of 19 pond samples were obtained from small-scale spirulina farms and subjected to metagenome and/or virome sequencing, and the results were analysed. A remarkable level of prokaryotic and viral diversity was found to be present in the ponds, with Limnospira sp. and Arthrospira sp. sometimes being notably scarce. A detailed breakdown of prokaryotic and viral components of 15 samples is presented. Twenty putative Limnospira sp.-infecting bacteriophage contigs were identified, though no correlation between the performance of these cultures and the presence of phages was found. The high diversity of these samples prevented the identification of clear trends in sample performance over time, between ponds or when comparing successful and failed fermentations.

Aliidiomarina quisquiliarum sp. nov., isolated from landfill leachate

Bacterial strain Y-6^T, isolated from a landfill site in Yiwu, PR China, was characterized using a polyphasic taxonomy approach. Cells were Gram-stain-negative, aerobic, rod-shaped, motile by means of a single polar flagellum and formed pale beige colonies. Strain Y-6^T grew at 4-40 °C (optimal at 30-37 °C), pH 6.5-9.5 (optimal at pH 7.2-8.5) and in the presence of 0.5-10.0 % (w/v) NaCl (optimal at 1.0-3.0 %). Phylogenetic analysis revealed that strain Y-6^T was a member of the genus Aliidiomarina and closely related to Aliidiomarina taiwanensis MCCC 1A06493^T with a 16S rRNA sequence similarity of 98.2 %. The major cellular fatty acids of the isolate were iso-C_15 : 0, C_16 : 0, iso-C_17 : 0 and summed feature 9 (iso-C_17 : 1  ω9c and/or 10-methyl-C_16 : 0). Q-8 was the predominant ubiquinone. The major polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, aminoglycophospholipid, aminophospholipid, phospholipid, three glycolipids and two unknown lipids. The genomic DNA G+C content was 46.6 mol%. The digital DNA-DNA hybridization value between Y-6^T and A. taiwanensis MCCC 1A06493^T was 18.3 %. Strain Y-6^T had an average nucleotide identity value of 74.09 % with A. taiwanensis MCCC 1A06493^T. Results from the polyphasic taxonomy study support the conclusion that strain Y-6^T represents a novel Aliidiomarina species, for which the name Aliidiomarina quisquiliarum sp.nov. is proposed. The type strain is Y-6^T (=MCCC 1K06228^T=KCTC 82676^T).

Culture-dependent and culture-independent methods reveal microbe-clay mineral interactions by dissimilatory iron-reducing bacteria in an integral oilfield

Fe(III) may be reasonably considered as one of the most important electron acceptors in petroleum reservoir ecosystems. The microbial mineralization of clay minerals, especially montmorillonite, is also of great significance to the exploration of petroleum and gas reservoirs. The bioreduction mechanisms of iron-poor minerals in petroleum reservoirs have been poorly investigated. This study investigated the bioreduction of montmorillonite by dissimilatory iron-reducing bacteria (DIRB) in petroleum reservoirs based on culture-independent and culture-dependent methods. Microbial diversity analysis revealed that Halolactibacillus, Bacillus, Alkaliphilus, Shewanella, Clostridium, and Pseudomonas were the key genera involved in the bioreduction of Fe(III). Through the traditional culture-dependent method, most of the key genera were isolated from the samples collected from petroleum reservoirs. Traditional culture-dependent methods can be used to reveal the metabolic characteristics of microorganisms (such as iron-reduction efficiency) to further elucidate the roles of different species (B. subtilis and B. alkalitelluris) in the environment. Moreover, many species with high iron-reduction efficiencies and relatively low abundances in the samples, such as Tessaracoccus and Flaviflexus, were isolated from petroleum reservoirs for the first time. The combination of culture-dependent and culture-independent methods can be used to further the understanding of the microbial communities and the metabolic characteristics of DIRB in petroleum reservoirs. Structural alterations that occurred during the interactions of microorganisms and montmorillonite were revealed through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray powder diffraction (XRD). The physical and chemical analysis results demonstrated that microorganisms from petroleum reservoirs can dissolve iron-poor montmorillonite and promote the release of interlayer water. The secondary minerals illite and clinoptilolite were observed in bioreduced smectite. The formation of secondary minerals was closely related to the dissolution degrees of minerals based on iron reduction.

Aliidiomarina halalkaliphila sp. nov., a haloalkaliphilic bacterium isolated from a soda lake in Inner Mongolia Autonomous Region, China

A haloalkaliphilic strain (IM 1326^T) was isolated from brine sampled at a soda lake in the Inner Mongolia Autonomous Region, China. Cells of the strain were rod-shaped and motile. Strain IM 1326^T was able to grow at 4–42 °C (optimum, 37 °C) with 0–13.0 % (w/v) NaCl concentrations (optimum at 4.0–6.0 %) and at pH 7.5–11.0 (optimum at 9.0–10.0). The 16S rRNA gene phylogenetic analysis revealed that the isolate belongs to the genus Aliidiomarina and is closely related to the type strains of Aliidiomarina sanyensis (95.8 % sequence similarity), Aliidiomarina shirensis (95.7 %), Aliidiomarina iranensis (95.4 %) and Aliidiomarina haloalkalitolerans (95.3 %). The whole genome of strain IM 1326^T was sequenced, and the genomic DNA G+C content was 49.7 mol%. Average nucleotide identity, average amino acid identity and digital DNA–DNA hybridization values between the isolate and the related Aliidiomarina species were 68.1–84.9 %, 76–78 % and 18.4–20.4 %, respectively. The respiratory quinone was ubiquinone-8. The polar lipid profile included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and one unidentified aminophospholipid. The predominant cellular fatty acids were summed feature 9 (10-methyl-C_16 : 0/iso-C_17 : 1 ω9c, 22.2 %), iso-C_15 : 0 (16.1 %) and iso-C_17 : 0 (13.1 %). Based on the results of phylogenetic analysis, genome relatedness, and the physiological and chemotaxonomic properties of the isolate, strain IM 1326^T is considered to represent a novel species of the genus Aliidiomarina, for which the name Aliidiomarina halalkaliphila sp. nov. is proposed (type strain IM 1326^T=CGMCC 1.17056^T=JCM 34227^T).

Bacterial Communities in Concrete Reflect Its Composite Nature and Change with Weathering

Concrete is an extreme but common environment and is home to microbial communities adapted to alkaline, saline, and oligotrophic conditions. Microbes inside the concrete that makes up buildings or roads have received little attention despite their ubiquity and capacity to interact with the concrete. Because concrete is a composite of materials which have their own microbial communities, we hypothesized that the microbial communities of concrete reflect those of the concrete components and that these communities change as the concrete ages. Here, we used a 16S amplicon study to show how microbial communities change over 2 years of outdoor weathering in two sets of concrete cylinders, one prone to the concrete-degrading alkali-silica reaction (ASR) and the other having the risk of the ASR mitigated. After identifying and removing taxa that were likely laboratory or reagent contaminants, we found that precursor materials, particularly the large aggregate (gravel), were the probable source of ∼50 to 60% of the bacteria observed in the first cylinders from each series. Overall, community diversity decreased over 2 years, with temporarily increased diversity in warmer summer months. We found that most of the concrete microbiome was composed of Proteobacteria, Firmicutes, and Actinobacteria, although community composition changed seasonally and over multiyear time scales and was likely influenced by environmental deposition. Although the community composition between the two series was not significantly different overall, several taxa, including Arcobacter, Modestobacter, Salinicoccus, Rheinheimera, Lawsonella, and Bryobacter, appear to be associated with ASR.

IMPORTANCE Concrete is the most-used building material in the world and a biologically extreme environment, with a microbiome composed of bacteria that likely come from concrete precursor materials, aerosols, and environmental deposition. These microbes, though seeded from a variety of materials, are all subject to desiccation, heating, starvation, high salinity, and very high pH. Microbes that survive and even thrive under these conditions can potentially either degrade concrete or contribute to its repair. Thus, understanding which microbes survive in concrete, under what conditions, and for how long has potential implications for biorepair of concrete. Further, methodological pipelines for analyzing concrete microbial communities can be applied to concrete from a variety of structures or with different types of damage to identify bioindicator species that can be used for structural health monitoring and service life prediction.

Sphingobacterium olei sp. nov., isolated from oil-contaminated soil

A Gram-stain-negative, rod-shaped, non-motile and non-spore-forming bacterium, designated HAL-9T, was isolated from oil-contaminated soil in Daqing oilfield, Heilongjiang Province, PR China. Strain HAL-9T was able to degrade quizalofop-p-ethyl and diclofop-methyl. Growth was observed at 10–35 °C (optimum, 30 °C), pH 6.0–10.0 (optimum, pH 7.0) and salinity of 0 %–5.0 % (w/v; optimum 1.0 %). The results of phylogenetic analysis based on the 16S rRNA gene indicated that strain HAL-9T belongs to the genus Sphingobacterium and showed the highest sequence similarity (98.3 %) to Sphingobacterium alkalisoli Y3L14T, followed by Sphingobacterium mizutaii DSM 11724T (95.1 %) and Sphingobacterium lactis DSM 22361T (95.1 %). Menaquinone-7 (MK-7) was the only isoprenoid quinone. The predominant cellular fatty acids were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), iso-C15: 0 and iso-C17 : 0 3-OH. The major polar lipids were phosphatidylethanolamine, three phosphoglycolipids and three unidentified lipids. The draft genome of strain HAL-9T was 5.41 Mb. The G+C content of strain HAL-9T was 40.6 mol%. Furthermore, the average nucleotide identity and in silico DNA–DNA hybridization values between strain HAL-9T and S. alkalisoli Y3L14T were 86.2 % and 32.8 %, respectively, which were below the standard thresholds for species differentiation. On the basis of phenotypic, genotypic and phylogenetic evidence, strain HAL-9T represents a novel species in the genus Sphingobacterium , for which the name Sphingobacterium olei sp. nov. is proposed. The type strain is HAL-9T (=ACCC 61581T=CCTCC AB 2019176T=KCTC 72287T).

Salino-alkaline lime of anthropogenic origin a reservoir of diverse microbial communities

This paper presents study on the microbiome of a unique extreme environment - saline and alkaline lime, a by-product of soda ash and table salt production in Janikowo, central Poland. High-throughput 16S rDNA amplicon sequencing was used to reveal the structure of bacterial and archaeal communities in the lime samples, taken from repository ponds differing in salinity (2.3-25.5% NaCl). Surprisingly abundant and diverse bacterial communities were discovered in this extreme environment. The most important geochemical drivers of the observed microbial diversity were salinity, calcium ions, nutrients, and water content. The bacterial and archaeal communities in saline, alkaline lime were similar to those found in natural haloalkaline environments. Although the archaeal contribution to the whole microbial community was lower than 4%, the four archaeal genera Natronomonas, Halorubrum, Halobellus, and Halapricum constituted the core microbiome of saline, alkaline lime - a set of OTUs (> 0.1% of total archaeal relative abundance) present in all samples under study. The high proportion of novel, unclassified archaeal and bacterial sequences (not identified at 97% similarity level) in the 16S rRNA gene libraries indicated that potentially new genera, especially within the class of Thermoplasmata inhabit this unique environment.

Diversity of cultivated aerobic poly-hydrolytic bacteria in saline alkaline soils

Alkaline saline soils, known also as “soda solonchaks”, represent a natural soda habitat which differs from soda lake sediments by higher aeration and lower humidity. The microbiology of soda soils, in contrast to the more intensively studied soda lakes, remains poorly explored. In this work we investigate the diversity of culturable aerobic haloalkalitolerant bacteria with various hydrolytic activities from soda soils at different locations in Central Asia, Africa, and North America. In total, 179 pure cultures were obtained by using media with various polymers at pH 10 and 0.6 M total Na⁺. According to the 16S rRNA gene sequence analysis, most of the isolates belonged to Firmicutes and Actinobacteria. Most isolates possessed multiple hydrolytic activities, including endoglucanase, xylanase, amylase and protease. The pH profiling of selected representatives of actinobacteria and endospore-forming bacteria showed, that the former were facultative alkaliphiles, while the latter were mostly obligate alkaliphiles. The hydrolases of selected representatives from both groups were active at a broad pH range from six to 11. Overall, this work demonstrates the presence of a rich hydrolytic bacterial community in soda soils which might be explored further for production of haloalkalistable hydrolases.

Arenimonas soli sp. nov., isolated from saline-alkaline soil

A Gram-staining-negative, non-motile, aerobic bacterial strain, designated Y3L17T, was isolated from the saline-alkaline soil of a farmland, Hangjin Banner, Inner Mongolia, northern China. Y3L17T could grow at 15-45 °C (optimum 35 °C), pH 6.0-10.0 (optimum pH 8.0) and with 0-4 % (w/v) NaCl (optimum 0 %). The results of phylogenetic analysis based on the 16S rRNA gene and gyrB gene sequences revealed that Y3L17T tightly clustered with strains of members of the genus Arenimonas, sharing the highest 16S rRNA gene similarities with Arenimonas aestuarii S2-21T (99.5 %) and Arenimonas donghaensis HO3-R19T (98.2 %), and lower similarities (<97 %) with all the other type strains of species of this genus. However, Y3L17T shared only 92.62 % gyrB gene similarities with A. aestuarii S2-21T. The DNA-DNA hybridization values of Y3L17T with A. aestuariiS2-21T and A. donghaensis HO3-R19T were 20.1±2.5 and 18.2±3.2 %, respectively. Y3L17T contained phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, five unknown phospholipids and one unknown lipid as the major polar lipids. Ubiquinone-8 (Q-8) was the predominant respiratory quinone, while iso-C15 : 0, iso-C17 : 0ω9c and iso-C11 : 0 3-OH were the major cellular fatty acids. Its genomic DNA G+C content was 65.4 mol%. On the basis of its phenotypic, phylogenetic and genotypic characteristics, Y3L17T represents a novel species within the genus Arenimonas, for which the name Arenimonas soli sp. nov. is proposed, the type strain is Y3L17T (=CGMCC 1.15905T =KCTC 52420T).