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The ever growing concerns about the impact of first generation bioethanol on food chain and on biodiversity have shifted the focus of research to second generation (2G) bioethanol technologies. The 2G-bioethanol's production relies on biomass feedstock that could provide a more sustainable energy generation without compromising food security and environment. Indeed, this production process exploits non-food crops, food crops residues, wastes of wood-based or food-based industries such as wood chips, skins or pulps from fruit pressing, respectively. Nevertheless, the industrial process of 2G-bioethanol's production is still in its infancy, indeed the future and the sustainability of the 2G-bioethanol strongly depend upon the development of the current technology. In this paper particular attention will be paid to the role of thermophilic microorganisms and their enzymes to the biotechnology's development of the bioethanol's production process.

Background: Due to its wide range of applications in the food, pharmaceutical and chemical fields, microbial syn- thesis of succinic acid is receiving growing attention, generating already relevant industrial results, as well as fueling constant research for improvements. In order to develop a sustainable process, a special focus is now set on the exploitation and conversion of lignocellulosic biomasses into platform chemicals. Results: In the present work we used Basfia succiniciproducens BPP7 in separated hydrolysis and fermentation experi- ments with Arundo donax as starting material. Fed-batch strategies showed a maximal production of about 37 g/L of succinic acid after 43 h of growth and a productivity of 0.9 g/L h on the pilot scale. Global mass balance calculations demonstrated a hydrolysis and fermentation efficiency of about 75%. Moreover, the application of a material flow analysis showed the obtainment of 88.5 and 52 % of succinic acid, per kg of virgin biomass and on the total generated output, respectively. Conclusions: The use of fed-batch strategies for the growth of B. succiniciproducens on A. donax improved the titer and productivity of succinic acid on pre-pilot scale. Process evaluation through material flow analysis showed successful results and predicted a yield of succinic acid of about 30% in a fed-batch process that uses A. donax as only carbon source also in the feed. Preliminary considerations on the possibility to achieve an energetic valorization of the residual solid coming from the fermentation process were also carried out. Keywords: Basfia succiniciproducens, Arundo donax, Fed-batch, Succinic acid, Pre-pilot scale, Inhibition, Material flow analysis

Processing and selection of fruits and vegetables generate high quantities of wastes that represent an economic and environmental issue for the agroindustry sector. According to the so-called “biorefinery” approach, this biomass can be exploited for the recovery of value-added molecules. In this study, the residues of industrial processing of tomato (Lycopersicon esculentum variety “Hybrid Rome”), fennel (Foeniculum vulgare), potato (Solanum tuberosum) and carrot (Daucus carota) were used as sole carbon sources to support cheap and sustainable microbial growth as well as the production of secondary metabolites (hydrogen and ethanol) by Thermoanaerobacterium thermostercoris strain BUFF, a thermophilic anaerobic microorganism isolated from buffalo-dung compost. Moreover, the use of hemicellulolytic enzymes of T. thermostercoris was assayed in the bioconversion reaction of the polymer fraction extracted from the rhizome of giant reed (Arundo donax) and of the leaves and stems of cardoon (Cynara cardunculus), dedicated non-food crops employed in energy supply.

Background Due to its wide range of applications in the food, pharmaceutical and chemical fields, microbial synthesis of succinic acid is receiving growing attention, generating already relevant industrial results, as well as fueling constant research for improvements. In order to develop a sustainable process, a special focus is now set on the exploitation and conversion of lignocellulosic biomasses into platform chemicals. Results In the present work we used Basfia succiniciproducens BPP7 in separated hydrolysis and fermentation experiments with Arundo donax as starting material. Fed-batch strategies showed a maximal production of about 37 g/L of succinic acid after 43 h of growth and a productivity of 0.9 g/L h on the pilot scale. Global mass balance calculations demonstrated a hydrolysis and fermentation efficiency of about 75%. Moreover, the application of a material flow analysis showed the obtainment of 88.5 and 52 % of succinic acid, per kg of virgin biomass and on the total generated output, respectively. Conclusions The use of fed-batch strategies for the growth of B. succiniciproducens on A. donax improved the titer and productivity of succinic acid on pre-pilot scale. Process evaluation through material flow analysis showed successful results and predicted a yield of succinic acid of about 30% in a fed-batch process that uses A. donax as only carbon source also in the feed. Preliminary considerations on the possibility to achieve an energetic valorization of the residual solid coming from the fermentation process were also carried out. Electronic supplementary material The online version of this article (10.1186/s13068-019-1362-6) contains supplementary material, which is available to authorized users.

Knowledge of Antarctic habitat biodiversity, both marine and terrestrial, has increased considerably in recent years, causing considerable development in the studies of life science related to Antarctica. In the Austral summer 1986−1987, a new thermophilic bacterium, Parageobacillus thermantarcticus strain M1 was isolated from geothermal soil of the crater of Mount Melbourne (74°22′ S, 164°40′ E) during the Italian Antarctic Expedition. In addition to the biotechnological potential due to the production of exopolysaccharides and thermostable enzymes, successful studies have demonstrated its use in the green chemistry for the transformation and valorization of residual biomass and its employment as a suitable microbial model for astrobiology studies. The recent acquisition of its genome sequence opens up new opportunities for the use of this versatile bacterium in still unexplored biotechnology sectors.

A bacterial strain, designated as strain 3 and identified as a member of the Thermosipho species on the basis of its phenotypic and genotypic characteristics, was isolated from a deep sea hydrothermal vent. Sequence analysis of the 16S rRNA gene revealed that its closest neighbor was Thermosipho africanus (99.5 %). This isolate Thermosipho sp. strain 3 (DSM 27729), a thermophilic, anaerobic, fermentative hydrogen-producing bacterium, produced a thermostable endocellulase that hydrolyzes carboxymethylcellulose (CMC) and β-glucan. The cellulase was purified and its activity characterized. The estimated molecular weight of the protein was about 40 kDa as determined by gel-filtration chromatography, SDS-PAGE and zymogram analyses. The optimal cellulase activity was at pH 5.5 and at a temperature of 80 °C. The enzyme was thermostable with about 50 % residual activity after 48 h and 4 h at 60 °C and 70 °C, respectively. Interestingly, endocellulase activity was increased about 2-fold by 5 mM MnCl2. MALDI-TOF PMF and the N-terminal amino acid sequence analyses of the purified enzyme revealed the extensive homology of the protein with a glycoside hydrolase family protein from Thermosipho africanus (NCBI protein accession number: 419759359; UniProt: K2PFP0).

The ever growing concerns about the threats of first generation bioethanol on food supplies and biodiversity have shifted the focus of research to second generation biofuel technologies. The second generation bioethanol's technologies provide sustainable energy without compromising food security and environment since they exploit non-food crops or non-food parts of crops and wastes of wood-based or food-based industries such as wood chips, skins and pulp from fruit pressing. The key step of the bioethanol's production processes is represented by the hydrolysis of the biomass to C5 and C6 sugars: such process relies on the use of bacterial enzymes that are mainly derived from extremophilic microorganisms. These microorganisms can be found in extreme environments, generally characterized by atypical temperature, pH, pressure, salinity, toxicity and radiation levels. Their enzymes (also named extremozymes) possess unique properties of considerable biotechnological significance that make them very useful for the industrial transformation of biomass to ethanol. In this report a survey of extremophiles and related enzymes that have been used for the bioconversion of waste biomass (not in competition with food chain) to bioethanol, is given.

Extreme marine environments have been the subject of many studies and scientific publications. For many years, these environmental niches, which are characterized by high or low temperatures, high-pressure, low pH, high salt concentrations and also two or more extreme parameters in combination, have been thought to be incompatible to any life forms. Thanks to new technologies such as metagenomics, it is now possible to detect life in most extreme environments. Starting from the discovery of deep sea hydrothermal vents up to the study of marine biodiversity, new microorganisms have been identified, and their potential uses in several applied fields have been outlined. Thermophile, halophile, alkalophile, psychrophile, piezophile and polyextremophile microorganisms have been isolated from these marine environments; they proliferate thanks to adaptation strategies involving diverse cellular metabolic mechanisms. Therefore, a vast number of new biomolecules such as enzymes, polymers and osmolytes from the inhabitant microbial community of the sea have been studied, and there is a growing interest in the potential returns of several industrial production processes concerning the pharmaceutical, medical, environmental and food fields.

Cellulases are a important family of hydrolytic enzymes which catalyze the bond of cellulose and other related cello-oligosaccharide derivates. Industrial applications require enzymes highly stable and economically viable in terms of reusability. These costs can be reduced by immobilizing the cellulases, offering a potential solution through enzyme recycling and easy recovery. The covalent immobilization of enzymes is reported here: one is commercial cellulase from Aspergillus Niger and other one is recombinant enzyme, named CelStrep it because was isolated from a new cellulolytic strain, Streptomyces sp. G12,. The optimal pH for binding is 4.6 for both cellulases and the optimal enzyme concentrations are 1 mg/mL and 5 mg/mL respectively. The support for immobilization is a poliacrylic matrix. Experiments carried out in this work show positive results of enzyme immobilization in terms of efficiency and stability and confirm the economic and biotechnical advantages of enzyme immobilization for a wide range of industrial applications.

Biorefinery residues from non-food biomasses are promising sources of sustainable agrochemicals. The molecular properties of water-soluble extracts from ligno-cellulosic biomass pretreated first by steam-explosion and then by enzymatic hydrolyses at different buffer doses, were assayed for bioactivity on maize. 13C and 31P nuclear magnetic resonance (NMR) spectra showed that extracts varied in phenolic and carboxyl content, while high performance size exclusion chromatography and diffusion ordered spectroscopy NMR revealed that Ox-BYP 1 obtained from wastes treated with a greater buffer dose contained small-sized molecules associated in apparently large metastable aggregates. Ox-BYP 2 separated from wastes treated with smaller buffer concentrations showed a more stable conformation. Both hydrolysates revealed a positive dose-dependent bioactivity toward maize growth. Ox-BYP 1 promoted plant fresh and dry weights and root length at 10 and 100 ppm but decreased seedling growth at 1 ppm. Instead, Ox-BYP 2 increased the whole plant growth at all assayed concentrations. Their different biostimulation effects were attributed to the toxicity of easily bioaccessible lignin-derived phenolics at small concentrations of Ox-BYP 1, which was removed by molecular selfassembly at greater concentrations. Conversely, the more strongly associated Ox-BYP 2 exerted a positive bioactivity even at small doses. The bioactivity of extracts from biorefinery wastes appeared to depend on molecular composition and, in turn, on waste pretreatments.

This study reports the purification and biochemical characterization of a raw starch-digesting α-amylase from Geobacillus thermoleovorans subsp. stromboliensis subsp. nov. (strain PizzoT). The molecular weight was estimated to be 58 kDa by SDS–PAGE. The enzyme was highly active over a wide range of pH from 4.0–10.0. The optimum temperature of the enzyme was 70°C. It showed extreme thermostability in the presence of Ca2+, retaining 50% of its initial activity after 90 h at 70°C. The enzyme efficiently hydrolyzed 20% (w/v) of raw starches, concentration normally used in starch industries. The α-amylase showed an high stability in presence of many organic solvents. In particular the residual activity was of 73% in presence of 15% (v/v) ethyl alcohol, which corresponds to ethanol yield in yeast fermentation process. By analyzing its complete amyA gene sequence (1,542 bp), the enzyme was proposed to be a new α-amylase.

Sea environments harbor a wide variety of life forms that have adapted to live in hard and sometimes extreme conditions. Among the marine living organisms, extremophiles represent a group of microorganisms that attract increasing interest in relation to their ability to produce an array of molecules that enable them to thrive in almost every marine environment. Extremophiles can be found in virtually every extreme environment on Earth, since they can tolerate very harsh environmental conditions in terms of temperature, pH, pressure, radiation, etc. Marine extremophiles are the focus of growing interest in relation to their ability to produce biotechnologically useful enzymes, the so-called extremozymes. Thanks to their resistance to temperature, pH, salt, and pollutants, marine extremozymes are promising biocatalysts for new and sustainable industrial processes, thus representing an opportunity for several biotechnological applications. Since the marine microbioma, i.e., the complex of microorganisms living in sea environments, is still largely unexplored finding new species is a central issue for green biotechnology. Here we described the main marine environments where extremophiles can be found, some existing or potential biotechnological applications of marine extremozymes for biofuels production and bioremediation, and some possible approaches for the search of new biotechnologically useful species from marine environments.

This is the first report describing the purification and enzymatic properties of a native invertase (beta-D-fructosidase) in Thermotogales. The invertase of the hydrogen-producing thermophilic bacterium Thermotoga neapolitana DSM 4359 (hereby named Tni) was a monomer of about 47 kDa having an amino acid sequence quite different from other invertases studied up to now. Its properties and substrates specificity let us classify this protein as a solute-binding protein with invertase activity. Tni was specific for the fructose moiety and the enzyme released fructose from sucrose and raffinose and the fructose polymer inulin was hydrolyzed in an endo-type fashion. Tni had an optimum temperature of 85 degrees C at pH 6.0. At temperatures of 80-85 degrees C, the enzyme retained at least 50% of its initial activity during a 6 h preincubation period. Tni had a K(m) and k(cat)/K(m) values (at 85 degrees C and pH 6.0) of about 14 mM and 5.2 x 10(8) M(-1) s(-1), respectively.

A Gram-positive, spore-forming, halophilic bacterial strain, FP5(T), was isolated from a salt lake in southern Spain and subjected to a polyphasic taxonomic study. Strain FP5(T) was strictly aerobic. Cells were coccoidal, occurring singly or in clusters. The cell-wall pepticloglycan type of strain FP5(T) was A4 beta based on L-Orn-D-Asp. Strain FP5(T) was characterized chemotaxonomically by having MK-7 as the major menaquinone and anteiso-C-15:0, anteiso-C-17:0, iso-C-15:0 and iso-C-16:0 as the main fatty acids. The isolate grew optimally at 37 degrees C and in presence of 10 % NaCl; no growth was observed in the absence of NaCl. The DNA G + C content was 43.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain FP5(T) falls within the evolutionary radiation of species of the genus Halobacillus. Levels of 16S rRNA gene sequence similarity between strain FP5(T) and the type strains of nine recognized Halobacillus species were in the range 97.0-99.0%. Levels of DNA-DNA relatedness indicated that strain FP5(T) represents a genomic species that is distinct from recognized Halobacillus species. Strain FP5(T) could be differentiated from recognized Halobacillus species based on several phenotypic characteristics. On the basis of phenotypic, phylogenetic and genomic data, strain FP5(T) is considered to represent a novel species of the genus Halobacillus, for which the name Halobacillus alkaliphilus sp. nov. is proposed. The type strain is FP5(T) (=DSM 18525(T) =ATCC BAA-1361(T)).

Composting, often described as nature's way of recycling, is a self-heating, aerobic, solid-phase process, during which organic waste materials are biologically degraded into an extremely useful humus-like substance by means of various microorganisms. The main protagonists of this process are thermophilic microorganisms and their enzymes. From the composting sites of "Experimental Center of Composting" (SA), different strains were isolated that fall within the radiation of the genera Aeribacillus and Geobacillus. The strains isolated showed thermophilic cellulase, xylanase, ?-xylosidase and arabinofuranosidase activities. Their optimal temperature ranged between 60 and 70°C. These enzymes were preliminary used in the bioconversion reactions in order to degrade lignocellulosic biomass obtaining fermentable monosaccharides and oligosaccharides, that could be employed in different biotechnological fields.

Environmental concerns such as greenhouse gas emission and fossil fuels depletion, have driven increasing technological and economical interest in the study of biorefining processes in order to convert organic waste materials (biomass) into bioethanol, biodiesel, building blocks (chemicals) and biomaterials. Vegetable waste biomass is produced continuously at global level by agro-industries, agriculture and forestry and according to its origin, it can be distinguished in three main groups i.e.: food wastes, crop residues and forestry/wood residues. Plant biomass and vegetable industrial wastes such as lignocellulosic biomass is object of great interest since it can be hydrolysed to have starch, (hemi)cellulose and lignin that in turn will be converted in value added chemicals and/or biofuels. Pre-treatment steps using physico-chemical or enzymatic processes, make the conversion of lignocellulosic biomass into biofuels more expensive than the extraction of fossil fuels. This chapter underlines the capability of thermophiles and of their enzymes to bypass the problems and limits linked with the lignocellulosic biomass use. Studies concerning the exploitation of agro-waste as growth medium for the production of biotechnologically useful extremophilic microorganisms and their relative enzymes, the pre-treatment and digestion of lignocellulosic fractions in order to obtain mono- and oligosaccharides, the use of thermophilic enzymes in comparison to that of commercial, for a convenient set up of a total degrading process, the chemical procedures for the characterization of new compounds obtained from lignocellulosic materials, are also discussed. Moreover, the opportunity to employ thermophiles in the conversion of lignocellulosic materials into ethanol using only one step process, are also provided.

Composting, often described as nature's way of recycling, is a self-heating, aerobic, solid-phase process, during which organic waste materials are biologically degraded into an extremely useful humus-like substance by means of various microorganisms. The main protagonists of this process are thermophilic microorganisms and their enzymes. From the composting sites of "Experimental Center of Composting" (SA), different strains were isolated that fall within the radiation of the genera Aeribacillus and Geobacillus. The strains isolated showed thermophilic cellulase, xylanase, ?-xylosidase and arabinofuranosidase activities. Their optimal temperature ranged between 60 and 70°C. These enzymes were preliminary used in the bioconversion reactions in order to degrade lignocellulosic biomass obtaining fermentable monosaccharides and oligosaccharides, that could be employed in different biotechnological fields.

In the present work the recently isolated strain Basfia succiniciproducens BPP7 was evaluated for the production of succinic acid up to the pilot fermentation scale in separate hydrolysis and fermentation experiments on Arundo donax, a non-food dedicated energy crop. An average concentration of about 17g/L of succinic acid and a yield on consumed sugars of 0.75mol/mol were obtained demonstrating strain potential for further process improvement. Small scale experiments indicated that the concentration of acetic acid in the medium is crucial to improve productivity; on the other hand, interestingly, short-term (24h) adaptation to higher acetic acid concentrations, and strain recovery, were also observed.

The Cynara cardunculus hemicellulose fraction was recovered from its stem and leaf biomass and converted into valuable molecules by exploiting the extracellular xylanase and beta-xylosidase activities produced by the thermophilic bacterium Geobacillus thermantarcticus. Several degradation procedures for the arabinoglucuronoxylan extract were proposed by using efficient and different enzymatic preparations, containing both or only one xylanolytic activity of G. thermantarcticus. In particular, when the xylanase and beta-xylosidase activities were used separately in hydrolysis reactions, xyloglucurono-oligosaccharides or xylose were obtained with a yield of 32% and 62.6% respectively, with reference to the hemicellulosic extract. Furthermore, the synergic action of beta-xylosidase/xylanase activities was exploited in transglycosylation processes for the production of xylo-conjugated compounds; xylosides of primary alcohols with increasing carbon chains and aromatic alcohols were produced starting from the C. cardunculus hemicellulose, which was selected as a cheap donor. When 2-phenoxyethanol was selected as an acceptor, 2-phenoxyethyl beta-xyloside, xylobioside and xylotrioside were prepared with a yield of 38.5% with respect to the hemicellulosic extract and spectroscopically characterized.

An alkalitolerant and halotolerant bacterium, designated strain Sharm was isolated from a salt lake inside Ras Muhammad. The morphological, physiological and genetic characteristics were compared with those of related species of the genus Halomonas. The isolate grew optimally at pH 7.0, 5-15% NaCl at 35 degrees C. The cells were Gram-negative rods, facultative anaerobes. They accumulated glycine-betaine, as a major osmolyte, and ectoine and glutamate as minor components. The strain Sharm(T) biosynthetised alpha-glucosidase. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and a novel phosphoglycolipid as major components. Ubiquinone with nine repetitive unities (Q9) was the only quinone found and, nC16:0 and C19:0 with cyclopropane were the main cellular fatty acids, accounting for 87.3% of total fatty acids. The G + C content of the genomic DNA was 64.7 mol %. The 16S rRNA sequence analysis indicated that strain Sharm was a member of the genus Halomonas. The closest relatives of the strain Sharm were Halomonas elongata and Halomonas eurihalina. However, DNA-DNA hybridisation results clearly indicated that strain Sham was a distinct species of Halomonas. On the basis of the evidence, we propose to assign strain Sharm as a new species of the genus Halomonas, H. sinaiensis sp. nov, with strain Sharm(T) as the type strain (DSM 18067(T); ATCC BAA-1308(T)).

A halophilic, alkalitolerant bacterium, strain 20AGT, was isolated from an algal mat collected from a sulfurous spring located in Santa Maria Incaldana (Mondragone, Campania Region, southern Italy). The isolate is Gram-positive, ferments several carbohydrates and has motile, rod-shaped cells that do not sporulate. The isolate grows at pH 6·5–9·5 and in 5–20 % NaCl. On the basis of 16S rRNA gene sequence similarity, the strain was shown to belong to the genus Oceanobacillus; strain 20AGT showed 96·6 % 16S rRNA gene sequence similarity to the type strain of Oceanobacillus iheyensis, DSM 14371T, and 99·5 % similarity to Oceanobacillus oncorhynchi NCIMB 14022T. Levels of DNA–DNA relatedness between strain 20AGT and O. iheyensis DSM 14371T and O. oncorhynchi NCIMB 14022T were respectively 29·4 and 59·0 %. The G+C content of the DNA of strain 20AGT was 40·1 mol%. The predominant respiratory quinone was MK-7, phosphatidylglycerol and phosphatidylcholine were the predominant polar lipids and minor phospholipids were also detected. ai-C14 : 0, ai-C15 : 0 and i-C15 : 0 were the major fatty acids. Strain 20AGT accumulated osmolytes and produced exopolysaccharide. On the basis of phenotypic characteristics, phylogenetic data and DNA–DNA relatedness data, isolate 20AGT should be designated as the type strain of a subspecies of Oceanobacillus oncorhynchi, for which the name Oceanobacillus oncorhynchi subsp incaldanensis subsp. nov. is proposed. The type strain is 20AGT (=DSM 16557T=ATCC BAA-954T).

A thermophilic, spore-forming bacterial strain L1(T) was isolated from hot compost "Pomigliano Environment" s.p.a., Pomigliano, Naples, Italy. The strain was identified by using a polyphasic taxonomic approach. L1(T) resulted in an aerobic, gram-positive, rod-shaped, thermophilic with an optimum growth temperature of 68 degrees C chemorganotrophic bacterium which grew on hydrocarbons as unique carbon and energy sources and was resistant to heavy metals. The G+C DNA content was 43.5 mol%. Phylogenetic analysis of 16S rRNA gene sequence and Random Amplified Polymorphic DNA-PCR (RAPD-PCR) analysis of L1(T) and related strains showed that it forms within Geobacillus toebii, a separate cluster in the Geobacillus genus. The composition of cellular fatty acids analyses by Gas-Mass Spectroscopy differed from that typical for the genus Geobacillus in that it is lacking in iso-C15 fatty acid, while iso-C16 and iso-C17 were predominant. Isolates grew on a rich complex medium at temperatures between 55-75 degrees C and presented a doubling time (t(d)) of 2 h and 6 h using complex media and hydrocarbon media, respectively. Among hydrocarbons tested, n-decane (2%) was the more effective to support the growth (1 g/L of wet cells). The microorganism showed resistance to heavy metal tested during the growth. Furthermore, intracellular alpha-galactosidase and alpha-glucosidase enzymatic activities were detectable in the L1(T) strain. Based on phenotypic, phylogenetic, fatty acid analysis and results from DNA-DNA hybridization, we propose assigning a novel subspecies of Geobacillus toebii, to be named Geobacillus toebii subsp. decanicus subsp. nov., with the type strain L1(T) (=DSM 17041=ATCC BAA 1004).

A Gram-negative, aerobic, motile and rod-shaped haloalkaliphilic bacterial strain 5AGT (DSM 15293 and ATCC BAA-966) was isolated from water with algal mat of a mineral pool in Malvizza site (Campania-Italy) and was subjected to a polyphasic study. The isolate grew at temperature of 10.0-43.0 degrees C with an optimum at 37.0 degrees C. Strain 5AGT grew optimally in the presence of 10% NaCl and grew also in the absence of salt. The isolate grew in the pH range 7.0-10.0 with an optimum at pH 9.0. It accumulated glycine-betaine, ectoine, and glutamate, as osmoprotectants. Strain 5AGT was also characterized chemotaxonomically by having ubiquinone-8 (Q8) as the predominant isoprenoid quinone, phosphoethanolamine (PEA), phosphatidylglycerol (PG) and diphosphatidylglycerol (DPG), as major polar lipids and aiC16:0 and C18:1cis as the major fatty acids. The DNA G+C content was 63.7mol%. Phylogenetic analyses based on 16S rRNA gene sequence showed that the isolate belonged to the genus Halomonas. The DNA-DNA hybridization of the type strain 5AGT with the most related Halomonas campisalis showed a re-association value of 35.0%. On the basis of phenotypic properties and phylogeny, strain 5AGT should be placed in the genus Halomonas as a member of a novel species for which we propose the name Halomonas campaniensis sp. nov.

A haloalkalophilic Halomonas strain CRSS, isolated from salt sediments in Antarctica, produced exocellular polysaccharides (EPS) up to 2.9 g g(-1) dry cells. Acetate was the most efficient carbon source for EPS production. The composition of media strongly affected the nature of the polymers; a mannan and a xylo-mannan, were obtained when cells were grown on complex media. Acetate was the most efficient carbon source for EPS production and in presence of this substrate, a new polysaccharide, a fructo-glucan, was produced. The EPS fraction was composed by glucose, fructose, glucosamine and galactosamine in relative proportions of 1:0.7:0.3:trace.

The taxomony of strain M8, isolated from algal mat formed at the origin of a sulfurous spring in Rifieto (Savignano Irpino, Campania, Italy), was investigated in a polyphasic approach. The morphological, physiological and genetic characteristics were compared with of Planococcus and Planomicrobium species. The isolate grew optimally at pH 9.0, 1.8 M NaCl at 37 degrees C. The cells were Gram-positive cocci that form pairs, tetrads and aggregates of several cells. The isolate was aerobic/microaerophilic and accumulated glycine-betaine, as a major osmolyte, with minor components glutamate and an unknown compound. M8 was able to hydrolyse X-Glc (5-bromo-4-chloro-3-indoyl beta-d-glucopyranoside). The polar lipid profile consisted of phosphatidylglycerol and diphosphatidylglycerol as major components, and phosphocholine as a minor compound. MK8 was the only quinone found and the fatty acid composition was dominated by branched acids, mainly aiC15:0. The G+C content of DNA was 47.9% and its phylogenetic position was established by 16S rRNA gene sequencing as a member of the genus Planococcus. The DNA/DNA similarity of M8 to the type species Planococcus citreus was less than 55%. For this reason and for physiological and chemotaxonomic features, it is proposed to create a new species Planococcus rifietensis sp. nov.

Studies on extremophiles, microorganisms able to survive in extreme environments, are very helpful for the comprehension of life evolution; in fact they are the unique organisms of the Earth at the origin of life. They lie into the three domains of life ( Archaea , Bacteria , and Eukarya ) and can be found in environmental niches on Earth such as in hydrothermal vents and springs, in salty lakes, in halite crystals, in polar ice and lakes, in volcanic areas, in deserts, or under anaerobic conditions. The existence of life forms beyond the Earth requires an extension of the classical limits of life: the resistance of extremophilic organisms to harsh conditions in terms of temperature, salinity, pH, pressure, dryness, and desiccation makes these living organisms good putative candidates to assess the habitability of other planets. The ability to survive and proliferate in extreme conditions (pH, temperature, pressure, salt, and nutrients) produces a variety of biotechnologically useful molecules such as lipids, enzymes, polysaccharides, and compatible solutes that are employed in several industrial processes. There are many extremophilic enzymes and also endogenous compounds that are used with success for food industry, for preparation of the detergents, for pharmacological applications, and also for genetic studies. In particular enzymes that derive from thermophiles, and for this reason called thermozymes, represent an excellent sources of new catalysts of interest in industrial sectors.

A halophilic, thermotolerant Bacillus strain (B3-15), isolated from water of a shallow, marine hot spring at Vulcano Island (Eolian Islands, Italy), produced an exocellular polysaccharide at 165 mg l−1. It grew on kerosene as sole carbon source and was resistant to Cd2+, Zn2+, As2+ and Hg2+. From 16S rDNA analysis, strain B3-15 was related to B. licheniformis. The exopolysaccharide was a tetrasaccharide repeating unit essentially constituted by sugars having a manno-pyranosidic configuration.

Polysaccharidases from extremophiles are remarkable for specific action, resistance to different reaction conditions and other biotechnologically interesting features. In this article the action of crude extracts of thermophilic microorganisms (Thermotoga neapolitana, Geobacillus thermantarcticus and Thermoanaerobacterium thermostercoris) is studied using as substrate hemicellulose from one of the most interesting biomass crops, the giant reed (Arundo donax L.). This biomass can be cultivated without competition and a huge amount of rhizomes remains in the soil at the end of cropping cycle (10–15 years) representing a further source of useful molecules. Optimization of the procedure for preparation of the hemicellulose fraction from rhizomes of Arundo donax, is studied. Polysaccharidases from crude extracts of thermophilic microorganisms revealed to be suitable for total degradative action and/or production of small useful oligosaccharides from hemicelluloses from A. donax. Xylobiose and interesting tetra- and pentasaccharide are obtained by enzymatic action in different conditions. Convenient amount of raw material was processed per mg of crude enzymes. Raw hemicelluloses and pretreated material show antioxidant activity unlike isolated tetra- and pentasaccharide. The body of results suggest that rhizomes represent a useful raw material for the production of valuable industrial products, thus allowing to increase the economic efficiency of A. donax cultivation.

Thermoacidophilic and halotolerant microorganisms from the Antarctic continent were studied for their lipid modulation under stress growth conditions. Temperature-induced changes in complex lipids and fatty acids of four strains belonging to the genus Alicyclobacillus involved the relative proportions of different polar lipids and the synthesis of ω-cyclohexyl-acyl chains, which were favoured by high temperatures. Studies were carried out on the lipid composition of four strains of extremely halotolerant bacteria belonging to the genus Micrococcus grown at different salt concentrations from 0 up to 4.5 M NaCl. The main lipids found were two unidentified glycolipids and two phospholipids: 1,2 diacylglycero-3-phosphoryl-glycerol (PG) and cardiolipin (DPG). Among the strains analysed, the lipids of the Micrococcus strain Erebus were shown to be strongly influenced by salt concentrations, in that DPG and one glycolipid were absent at a low salt molarity while, under these conditions, PG was the main lipid found. The predominant fatty acids in all halotolerant strains were of the anteiso type; growth under increasing salinity gave rise to an increase in long chain fatty acids and of straight chain fatty acids, while a decrease in iso fatty acids occurred.

Summary A thermophilic aerobic microorganism, able to produce two exocellular polysaccharides (EPS1 and EPS2), was isolated from a shallow hydrothermal vent at Vulcano island (Eolian Islands, Italy). EPS1 and EPS2 were based on mannose and glucose although in a different ratio. EPS2 possessed a trisaccharide repeating unit with a manno-pyranoside configuration. New isolate phenotype was studied by physiological and morphological observations, including biochemical and antimicrobial susceptibility tests (134). Previous analyses carried out on 87 field isolates and 8 thermophilic reference bacilli displayed low phenotypic similarity level ( S SM = 65%) with Bacillus thermodenitrificans DSM 465. Optimal growth occurs at 65 °C and pH 7.0. Oxidase and catalase are negative. The guanine-plus-cytosine (G+C) content of DNA is 52.7%. Genotypic investigations demonstrated the diversity of the isolate with fifteen selected thermophilic Bacillus spp. when we compared the restriction patterns of the amplified 16S rDNA. The membrane lipids are based on fatty acids mainly belonging to the iso -family.

The morphological, physiological and genetic characteristics of an isolate cyanobacterium from hard sand of the lake Venere in the Pantelleria island (Italy) were described. The isolate with a small-size coiled helix shape, growing optimally at pH 9.2–9.5 at 30°C under continuous illumination and aeration, possessed a 61.5 mol% of Guanine + Cytosine content of DNA. The lipid profile showed the presence of mono-, di-glycosyl, sulphoquinovolosyl and phosphatidyl (MGDG, DGDG, SQDG and PG). The fatty acid profile was also studied, characterized by the absence of γ-linolenic acid and the presence of saturated and monounsaturated C16 and C18. The latter was also present as a dienoic component. The fatty acid composition was affected by growth temperature by increasing the degree of desaturation at a lower temperature and the biosynthesis of shorter acyl chains. The effects of growth conditions other than temperature, physical, nutritional and chemical on lipid composition were also studied. The overall features of the cyanobacterium isolated from Pantelleria clustered it into Spirulina genus.

Isolation and classification of extremophiles and cyanobacteria are described. Seven thermophiles, belonging to Bacillus genus, five acidothermophiles, classified as Alicyclobacillus, and five halotolerant cocci, belonging to Micrococcus genus, were isolated from Antarctic samples of geothermal and saline soils. The isolates were examined for their polar lipid and fatty acid composition. Changes in membrane lipids, induced by stressed growth conditions, were analysed. The isolation of two new cyanobacteria and their polysaccharide characterization were described. The exopolysaccharide production and characterization, as well as thermophilic xylan‐degrading enzymes, were studied.

Three halobacteria strains (T5, T6, T7), growing optimally at a sodium chloride concentration of 3.5 M, were isolated from samples collected in the Tunisian marine saltern located close to Monastir. Although they were different in colony and cell morphology, the isolates were similar in most respects and all produced a homopolyester identified spectroscopically as polyhydroxybutyrate when grown on carbohydrates. Under the same conditions, the isolates formed acidic exopolysaccharides. Acid methanolysis of their complex lipids released archaeol (2,3-di-O-phytanyl-sn-glycerol). All the isolates had polar lipid patterns characteristic of representatives of the genus Haloarcula. Partial sequence analysis of 16S rRNA genes from strain T5 confirmed its assignment to the genus Haloarcula. Although strain T5 differed phenotypically from the species Haloarcula japonica in several respects, DNA–DNA hybridization indicated that the T5 isolate is a new strain of H. japonica.

Exopolysaccharide (EPS) production and chemical composition of heterocystous and non-heterocystous cyanobacteria of subgroups 3, 4, and 5 together with four new species isolated from Pantelleria (Italy) hard sands and from a lake in the proximity of Edmonson Point in Antarctica were studied. The yield of extracellular soluble polysaccharides (RPS) and slime layers (CPS) showed a significant variation from one strain to another; generally RPS were more abundant than CPS with the exception of Anabaena torulosa and Scytonema hoffmanni. Phormidium sp. was the best producer of EPS. Among heterocystous cyanobacteria belonging to Nostocaceae the new species Anabaena WSAF and A. torulosa were found to produce the highest level of EPS. Among heterocystous cyanobacteria other than Nostocaceae, the best producer of EPS was Chlorogloeopsis sp. 6912. Four species were chosen for studying the effects of growth conditions, nutritional, physical and chemical, on total EPS formed. Glucose and galactose were the neutral sugars widely present in the species examined, although other sugars such as mannose and xylose were plentiful in some species. Amino-sugar, as glucosamine, and uronic acids were also found in EPS of some cyanobacteria. Finally the inhibition of avarol, a sesquiterpene hydroquinone, toxicity on Artemia salina by EPS of some species was analysed.

The isolation of three species from soil samples from an unexplored site in Antarctica, belonging to the Alicyclobacillus genus, is reported. The isolates, named MR1, MR2 and MR4, were from 30 samples of geothermal soil from Mount Rittmann. All the isolates had lipids based mainly on fatty acids possessing a terminal cyclohexane; hopanoid and quinones of MK-7 were also present. All isolates were characterized by phenotypic features and the isolate MR1 was subjected to genetic analyses. The isolates were thermoacidophilic, showing an optimum temperature of 63°C and an optimum pH of 3.5–4.0. They were able to grow in the temperature range 45–70°C. The percentage C+G of DNA of MR1 was 64.9% and showed a 16S rDNA similarity of 99.3% with Alicyclobacillus acidocaldarius ATCC 43034 and a DNA-DNA homology of 69.7% with A. acidocaldarius DSM 446. The strain MR1 is unable to produce amylolytic activity under different growth conditions. It is proposed to accommodate MR1 in the genus Alicyclobacillus as subspecies rittmannii of A. acidocaldarius.

Summary The morphological, physiological and genetic characteristics of an isolate (AAP) from hard sand of the lake of Venere in the Pantelleria island (Italy) were described. The isolate, growing optimally at pH 9.0 in the presence of 10% of NaCl at 33–35°C, was a Gram-negative pleomorphic rod, strictly aerobic, capable of accumulating polyhydroxybutyrate. The isolate was able to grow on different carbon sources in presence of thiamine or biotin. The G+C content of DNA was 65.02% and its phylogenetic position was elucidated by 16S rRNA cataloguing. The isolate AAP clustered phylogenetically within the gamma subclass of the Proteobacteria and is closely related to the other species on the Halomonas-Deleya branch. The haloalkalophilic strain should be placed in a new species of the genus Halomonas for which the name “Halomonas pantelleriense” is proposed.

The occurrence and the characterization of a polyhydroxybutyrate (PHB) in Anabaena cylindrica 10 C cultivated under different growth conditions were reported. The addition to the culture of A. cylindrica of appropriate precursors initiated the formation of a heteropolymer (PHB + PHV). The simultaneous occurrence of an exopolysaccharide and its partial characterization were also reported.

A novel thermophilic Gram-positive bacillus, “Bacillus thermoantarcticus”, isolated from geothermal soil near the crater of Mount Melbourne, is described. The organism grows at an optimal temperature of 63°C at pH 6.0, is oxidase-positive, catalase-negative and produces an exopolysaccharide, an exocellular xylanase, an intracellular alcohol dehydrogenase and exo- and endocellularα-glucosidase(s). The sequence of 16S rDNA is very similar to that of “Bacillus thermoglucosidasius”; however, the guanine-plus-cytosine (G + C) content is 8 mol% higher. The type strain is “Bacillus thermoantarcticus” (DSM 9572).

Summary Seven thermophilic strains isolated from different geographical areas of the Antarctic Continent were examined for their polar lipid pattern and fatty acid composition. Temperature induced changes in membrane lipids were also analysed. They involved the relative proportions of different polar lipids and the synthesis of higher melting point fatty acids, which was favoured by high temperatures. Taxonomic implications on the basis of fatty acid analysis were reported.

Five industrial Saccharomyces cerevisiae strains were evaluated for their suitability for strain improvement for future use in ethanol production processes. Principal components analysis of growth-related and production-related fermentation parameters of the 5 strains grown on glucose demonstrated the superiority of the Y9 strain in terms of its rapid growth and highest ethanol yields on both biomass and glucose. The growth and ethanol production performances of these strains on various agro-industrial wastes (including sugar beet pulp, starch and sugar beet molasses) and biological residues (including carrot, tomato and potato peel) were also determined. Ethanol tolerance studies, using both solid and liquid cultures, revealed the remarkable abilities of the BC187 and Y9 strains to survive and grow at high ethanol concentrations. Suspension cultures were found to be highly tolerant to 78.80 g L-1 ethanol however their growth ability showed a distinct decrease with increasing ethanol concentration such that only (1-2)% of the control growth was observed in media containing 118.20 g L-1 ethanol. The importance of choosing the appropriate S. cerevisiae strain to be used in ethanol production was clearly established with this study. Fermentation performances of the cultures under different cultivation conditions pointed to the fact that the choice of strain will not only depend on the ethanol tolerance but also on the preferential utilization of the carbon resources of biological residues. (c) 2012 Elsevier Ltd. All rights reserved.

Two thermophilic archaea belonging to the genus Sulfolobus, grown on glucose, produced an extracellular polysaccharide (EPS). The production of EPS conducted both in 90 1 fermentor and in batch culture reached the maximum during the stationary phase of growth. The chemical analysis (FT-IR, HPAE-PAD, UV, Optical Rotation) of the biopolymer and of its acid hydrolizate suggested glucose, mannose, glucosamine and galactose as major components of the sulfated heteropolysaccharide.