Identification of enzyme-producing thermophilic bacilli isolated from marine vents of Aeolian Islands (Italy)

Enzyme-producing thermophilic bacilli were isolated from different thermal sites located in and around Aeolian Islands (Italy) and characterised by both molecular and culture-based methods. Spore-forming bacteria with optimal growth from 45 to 70 °C were isolated from submarine vents and a geothermal well of Aeolian Islands (Italy). Eighteen selected strains were screened for extracellular enzyme presence by using nine substrates: Tween 20, Tween 80, tributyrin, soluble starch, xylan, dextran, carragenan, gelatine and casein. Sixteen isolates were able to grow at pH 9. The isolates were differentiated on the basis of restriction pattern of their amplified 16S rDNA (ARDRA) prior to 16S rRNA gene sequence analysis. On the basis of the most complete sequencing results strain V3 was identified asGeobacillus thermodenitrificans, most of isolates (10/14) was similar at high level (≥95%) to different reference strains of the speciesBacillus licheniformis. The remaining isolates, exhibiting sequence similarity below 95%, may represent novel species of the genusBacillus

The submarine hydrothermal system of Panarea (Southern Italy): biogeochemical processes at the thermal fluids-sea bottom interface

Among the submarine hydrothermal systems located off-shore the volcanic archipelago of the Eolian Islands (Southern Italy), the most active is located off the coasts of Panarea Island. Thermal waters, gases and sulphur deposits coexist at the sea bottom where hydrothermal fluids are released from both shallow and deep vents. The chemical and isotopic composition of the fluid phase shows the presence of a significant magmatic component and the physico-chemical conditions of the geothermal reservoir allow the release of reduced chemical species that are microbially mediated towards the production of organic carbon as a form of biochemical energy. Mi- croorganisms inhabiting this environment possess nutritional requirements and overall metabolic pathways ide- ally suited to such ecosystem that represents a clear example of the close connection between geosphere and biosphere. Microscopic examination of the white mat attached to rock surfaces showed the presence of Thio- thrix-like filamentous bacteria. Moderately thermophilic heterotrophic isolates were identified as strains of the genus Bacillus. Although the hydrothermal system of Panarea has to be considered a «shallow» system, it shows many characteristics that make it similar to the «deep» oceanic systems, giving a unique opportunity for improv- ing our knowledge on such an unexplored world by working at this easily accessible site

Phylogenetic Diversity of Archaea in Shallow Hydrothermal Vents of Eolian Islands, Italy

Shallow hydrothermal systems (SHS) around the Eolian Islands (Italy), related to both active and extinct volcanism, are characterized by high temperatures, high concentrations of CO2 and H2S, and low pH, prohibitive for the majority of eukaryotes which are less tolerant to the extreme conditions than prokaryotes. Archaea and bacteria are the key elements for the functioning of these ecosystems, as they are involved in the transformation of inorganic compounds released from the vent emissions and are at the basis of the hydrothermal system food web. New extremophilic archaea (thermophilic, hyperthermophilic, acidophilic, alkalophilic, etc.) have been isolated from vents of Vulcano Island, exhibiting interesting features potentially valuable in biotechnology. Metagenomic analyses, which mainly involved molecular studies of the 16S rRNA gene, provided different insights into microbial composition associated with Eolian SHS. Archaeal community composition at Eolian vent sites results greatly affected by the geochemistry of the studied vents, principally by hypersaline conditions and declining temperatures. Archaeal community in sediments was mostly composed by hyperthermophilic members of Crenarchaeota (class Thermoprotei) and Euryarchaeota (Thermococci and Methanococci) at the highest temperature condition. Mesophilic Euryarchaeota (Halobacteria, Methanomicrobia, and Methanobacteria) increased with decreasing temperatures. Eolian SHS harbor a high diversity of largely unknown archaea, and the studied vents may be an important source of new isolates potentially useful for biotechnological purposes

A Special Issue on Microorganisms from Extreme Environments in Memory of Luigi Michaud (1974–2014)

A special issue (SI) titled “Microbial Diversity in Extreme Environments: Implications for Ecological and Applicative Perspectives” has been launched with the aim of showcasing the diversity and biotechnological potential of extremophilic microorganisms. The issue includes 10 research papers and four reviews that mainly address prokaryotes inhabiting hyperarid, hypercold, hyperalkaline and hypersaline (or polyextreme) environments, spanning from deserts to meromictic and glacier lakes around the globe. Thermophilic prokaryotes from shallow hydrothermal vents and Antarctic geothermal soils are also treated. The ecology and biotechnological perspectives of eukaryotes are discussed in two review papers and one research paper. This special issue serves as a memorial to Dr. Luigi Michaud (1974–2014), who dramatically passed away in Antarctica during underwater sampling activities

Diversity of prokaryotes at a shallow submarine vent of Panarea Island (Italy) by high-throughput sequencing

To determine microbial community composition and possible key microbial processes in the shallow-sea hydrothermal vent system off Panarea Island (Italy), we examined bacterial and archaeal communities of sediment and fluid samples from a hot vent by 16S rDNA Illumina sequencing technique. Both high abundant (>1% of total sequences), low abundant (from 0.1 to <1%) and rare (< 0.1%) phylogenetic groups were responsible for the distinct prokaryotic communities characterizing the heated sediment and fluid. The bacterial and archaeal communities from sediment were dominated by sequences affiliated with Rhodovulum genus (Alphaproteobacteria), including phototrophic ferrous-iron-oxidizing purple bacteria, Thiohalospira and Thiomicrospira (Gammaproteobacteria), typically involved in the sulphur cycle, and Methanococcus (Euryarchaeota). Fluid communities were dominated by anoxygenic phototrophic members of Chlorobium, followed by Thiomicrospira (Gammaproteobacteria), Sulfurimonas, Arcobacter and Sulfurospirillum (Epsilonproteobacteria), and Methanosarcina (Euryarchaeota). Obtained sequences were affiliated with prokaryotes taking a key part in the carbon, iron and sulphur cycling at the shallow hydrothermal system off Panarea Island. Despite the huge sequencing efforts, a great number of Bacteria and Archaea still remains unaffiliated at genus level, indicating that Black Point vent represents a hotspot of prokaryotic diversity

Exploring Mediterranean and Arctic Environments as a Novel Source of Bacteria Producing Antibacterial Compounds to be Applied in Aquaculture

The need to discover new natural compounds has become urgent as a possible alternative solution to contrast the spread of antibiotic resistance, also in the aquaculture field. Bacterium&ndash;bacterium inhibitory activity against bacterial pathogens relevant in aquaculture was evaluated on agar plates for bacteria isolated from cold Arctic (Kongsfjorden, Svalbard Islands; i.e., seawater and sediment samples) and temperate Mediterranean (Lake Faro in Messina and the Straits of Messina, Italy; i.e., brackish water and benthic filter-feeding organisms) environments. Cell-free supernatants (both pure and concentrated 10-fold) were further assayed and, in the case of a positive response, crude extracts were obtained and tested. After the pre-screening procedures, about 30% of the bacterial isolates inhibited the growth of at least one pathogen used as a target. The 10-fold concentrated supernatants of two Arctic Salinibacterium spp. strains and the Mediterranean Bacillus sp. PS62 (associated with the pennatulacean Pteroeides spinosum Ellis, 1764) resulted in being active against P. damselae subsp. piscicida. The crude extracts obtained from Bacillus sp. PS62 also showed inhibitory activity against the same pathogen. Our findings suggest that tested bacteria could represent a novel source of compounds to be applied to overcome pathogenesis in the aquaculture field

A polyphasic taxonomic study of thermophilic bacilli from shallow, marine vents

Summary Eighty-seven thermophilic, aerobic, spore-forming bacteria were isolated from shallow, marine, thermal vents of the Eolian Islands (Italy) and tested for a broad spectrum of phenotypic characteristics. A numerical taxonomy study was performed on these isolates and 8 thermophilic Bacillus and Geobacillus reference strains by 89 selected features. Results from cluster analysis showed the formation of nine clusters. Most of the isolates (83%) fell into several phenetically well distinguished clusters, loosely related to Geobacillus thermodenitrificans. The remaining isolates grouped together with different reference strains. Eighteen isolates, representative of the different clusters, were selected for subsequent genotypic characterisation, including partial 16S rDNA sequence analysis of 18 strains and almost complete 16S rDNA sequences of 9 strains. Subsequent DNA/DNA reassociation studies and determination of the base composition of DNA identified seven isolates as Geobacillus thermodenitrificans, two isolates as G. thermoleovorans and one isolate as Bacillus pallidus. Four isolates represented two novel species of Bacillus. The remaining four represented novel Geobacillus species, one of which has recently been described as Bacillus vulcani DSMZ 13174 T

Innovative Process for Dried Caper (<i>Capparis spinosa</i> L.) Powder Production

This research aimed to develop a new time, energy, and cost-saving production process for obtaining dried powder from Capparis spinosa floral buds. Four different trials, including dry salting with 40% NaCl (for 10 days and 40 days) and brine salting with 18% NaCl (at room temperature for 3 days and at 60 °C for 6 h), were carried out, and two different air-drying temperatures (40 and 50 °C) were used. The effects on chemical and sensory characteristics were investigated and compared with traditional undried caper samples. Spectroscopy and chromatographic techniques such as UV–VIS, GC-MS, and FTIR were used for chlorophylls, carotenoids, polyphenols, flavonoids, and volatile aroma compounds’ analyses. Moreover, a sensory descriptive analysis and acceptability were applied to individuate the product most appreciated by the consumers. Among the different trials, brine salting at 60 °C and drying at 50 °C constituted the fastest process that yielded an appreciated powder by consumers; the chemical analyses demonstrated that this process did not lead to the formation of extraneous aroma compounds that could influence the typical sensory properties of capers and maintained high levels of chlorophylls, carotenoids, and polyphenols. Altogether, the results could be of great significance to industrial production and potentiate positive impacts on the economy of production areas

Hydrating Capabilities of the Biopolymers Produced by the Marine Thermophilic Bacillus horneckiae SBP3 as Evaluated by ATR-FTIR Spectroscopy

The surfactin-like lipopeptide (BS-SBP3) and the exopolysaccharide (EPS-SBP3) produced by the polyextremophilic Bacillus horneckiae SBP3 (DSM 103063) have been recently described as valuable biopolymers useful in biotechnological applications. To investigate the hydrating capabilities of BS-SBP3 and EPS-SBP3, here we evaluated (i) their wetting properties, measuring the contact angle; (ii) their moisture uptake abilities using the gravimetric method; and (iii) their hydrating states (from 0 to 160% w/w of water content) using ATR-FTIR spectroscopy. BS-SBP3 reduced the water contact angle on a hydrophobic surface from 81.7&deg; to 51.3&deg;, whereas the contact angle in the presence of EPS-SBP3 was 72.9&deg;, indicating that BS-SBP3 improved the wettability of the hydrophobic surface. In the moisture uptake tests, EPS-SBP3 absorbed more water than BS-SBP3, increasing its weight from 10 mg to 30.1 mg after 36 h of 100% humidity exposure. Spectral distance and cross-correlation analyses were used to evaluate the molecular changes of the two biopolymers during the hydration process. As the water concentration increased, BS-SBP3 spectra changed in intensity in the two contributions of the OH-stretching band named &ldquo;closed&rdquo; and &ldquo;open&rdquo; (3247 and 3336 cm&minus;1, respectively). Differently, the spectra of EPS-SBP3 exhibited a broader peak (3257 cm&minus;1), which shifted at higher water concentrations. As evaluated by the spectral distance and the wavelet cross-correlation analysis, the OH-stretching bands of the BS-SBP3 and EPS-SBP3 changed as a function of water content, with two different sigmoidal trends having the inflection points at 80% and 48%, respectively, indicating peculiar water-properties of each biopolymer. As wetting agents, these biopolymers might replace industrially manufactured additives in agriculture and the food and cosmetic industries