Four sponge-associated Antarctic bacteria (i.e., sp. strains CAL384 and CAL396, sp. strain GW185, and sp. strain CAL606) were selected for the highly mucous appearance of their colonies on agar plates. The production of extracellular polymeric substances (EPSs) was enhanced by a step-by-step approach, varying the carbon source, substrate and NaCl concentrations, temperature, and pH. The EPSs produced under optimal conditions were chemically characterized, resulting in a moderate carbohydrate content (range, 15 to 28%) and the presence of proteins (range, 3 to 24%) and uronic acids (range, 3.2 to 11.9%). Chemical hydrolysis of the carbohydrate portion revealed galactose, glucose, galactosamine, and mannose as the principal constituents. The potential biotechnological applications of the EPSs were also investigated. The high protein content in the EPSs from sp. CAL384 was probably responsible for the excellent emulsifying activity toward tested hydrocarbons, with a stable emulsification index (E) higher than those recorded for synthetic surfactants. All the EPSs tested in this work improved the freeze-thaw survival ratio of the isolates, suggesting that they may be exploited as cryoprotection agents. The addition of a sugar in the culture medium, by stimulating EPS production, also allowed isolates to grow in the presence of higher concentrations of mercury and cadmium. This finding was probably dependent on the presence of uronic acids and sulfate groups, which can act as ligands for cations, in the extracted EPSs. To date, biological matrices have never been employed for the investigation of EPS production by Antarctic psychrotolerant marine bacteria. The biotechnological potential of extracellular polymeric substances produced by Antarctic bacteria is very broad and comprises many advantages, due to their biodegradability, high selectivity, and specific action compared to synthetic molecules. Here, several interesting EPS properties have been highlighted, such as emulsifying activity, cryoprotection, biofilm formation, and heavy metal chelation, suggesting their potential applications in cosmetic, environmental, and food biotechnological fields as valid alternatives to the commercial polymers currently used.

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.

In the last decades, research has focused on the capabilities of microbes to secrete exopolysaccharides (EPS), because these polymers differ from the commercial ones derived essentially from plants or algae in their numerous valuable qualities. These biopolymers have emerged as new polymeric materials with novel and unique physical characteristics that have found extensive applications. In marine microorganisms the produced EPS provide an instrument to survive in adverse conditions: They are found to envelope the cells by allowing the entrapment of nutrients or the adhesion to solid substrates. Even if the processes of synthesis and release of exopolysaccharides request high-energy investments for the bacterium, these biopolymers permit resistance under extreme environmental conditions. Marine bacteria like Bacillus, Halomonas, Planococcus, Enterobacter, Alteromonas, Pseudoalteromonas, Vibrio, Rhodococcus, Zoogloea but also Archaea as Haloferax and Thermococcus are here described as EPS producers underlining biopolymer hyperproduction, related fermentation strategies including the effects of the chemical composition of the media, the physical parameters of the growth conditions and the genetic and predicted experimental design tools.

Levan is a homopolymer of fructose with many outstanding properties like high solubility in oil and water, strong adhesiveness, good biocompatibility, and film-forming ability. However, its industrial use has long been hampered by costly production processes which rely on mesophilic bacteria and plants. Recently, Halomonas sp. AAD6 halophilic bacteria were found to be the only extremophilic species producing levan at high titers in semi-chemical medium containing sucrose, and in this study, pretreated sugar beet molasses and starch molasses were both found to be feasible substitutes for sucrose. Five different pretreatment methods and their combinations were applied to both molasses types. Biomass and levan concentrations reached by the Halomonas sp. AAD6 cells cultivated on 30 g/L of pretreated beet molasses were 6.09 g dry cells/L and 12.4 g/L, respectively. When compared with literature, Halomonas sp. was found to stand out with its exceptionally high levan production yields on available fructose. Molecular characterization and monosaccharide composition studies confirmed levan-type fructan structure of the biopolymers. Rheological properties under different conditions pointed to the typical characteristics of low viscosity and pseudoplastic behaviors of the levan polymers. Moreover, levan polymer produced from molasses showed high biocompatibility and affinity with both cancerous and non-cancerous cell lines.

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An extremely halophilic archaeon belonging to the order Halobacteriales was isolated from Fuente de Piedra salt lake, Spain. This strain, designated FP1 T , was a pleomorphic coccoid, neutrophilic and required at least 15 % (w/v) NaCl for growth. Strain FP1T grew at 37-60 6C, with optimal growth at 50 6C. Mg 2+ was not required, but growth was observed with up to 10 % (w/v) MgSO 4 .Polar lipid analysis revealed the presence of mannose-6-sulfate(1-2)-glucose glycerol diether as a major glycolipid. Both C 20 C 20 and C 20 C 25 core lipids were present. Halophilic Archaea belonging to the order Halobacteriales are found in large numbers in the crystallizer ponds of solar salterns worldwide (Kamekura & Dyall-Smith, 1995;Oren et al., 1997;Grant, 2004; Fendrihan et al., 2006). Several saline and hypersaline environments in Spain have been studied and many halophiles have been isolated from them. A few studies have described halophilic bacteria from the Fuente de Piedra saline lake in the province of Malaga, southern Spain (Martinez-Canovas et al., 2004; MartinezCheca et al., 2005;Mata et al., 2006), but no extremely halophilic archaea have been described from this lake.In the present study, a novel member of the genus Tindall, 2003;Xu et al., 2005b;Wright, 2006;Castillo et al., 2006), a combination of other morphological and chemotaxonomic characters such as lipid analyses have been used to distinguish between species of these two genera.Strain FP1 T was isolated from samples collected during summer 2005 from Fuente de Piedra saline lake, Malaga province, southern Spain (37u 69 N 4u 449 W).Abbreviations: PG, phosphatidylglycerol; PGP-Me, phosphatidylglycerol phosphate methyl ester; PHB, poly-b-hydroxybutyric acid; S-DGD, mannose-6-sulfate(1-2)-glucose glycerol diether; S 2 -DGD, mannose-2,6-disulfate(1-2)-glucose glycerol diether.The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain FP1T is AM285297.A thin-layer chromatogram of total polar lipids and a table giving 13 C NMR assignments for polar lipids from strain FP1T and related species are available with the online version of this paper. G 2007 IUMS Printed in Great Britain1499 Cell morphology was determined by phase-contrast microscopy (Zeiss). Colony morphology was analysed on solid medium via a stereomicroscope (M8; Leica). Tolerance to NaCl and MgSO 4 and growth at various temperatures and pH were tested in medium 1. All growth tests were performed at the optimal growth temperature (50 uC) for 3 days. Sensitivity of the strain to antibiotics was tested by using medium 1 with agar (1.8 %, w/v) and Sensi-discs (6 mm; Oxoid) (Romano et al., 1993). Phenotypic tests were performed according to the proposed minimal standards for the description of novel taxa of the order Halobacteriales (Oren et al., 1997). Gelatin hydrolysis was determined as described by Oren et al. (2002). Casein hydrolysis and oxidase, tyrosinase, aminopeptidase (Bactident-Merck) and catalase activities were tested in medium 1 as described by Oren et al. (1997). For nit...

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.

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 FP5T was strictly aerobic.Cells were coccoidal, occurring singly or in clusters. The cell-wall peptidoglycan type of strain FP5 T was A4b 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 6C and in presence of 10 % NaCl; no growth was observed in the absence of NaCl. The genus Halobacillus can be differentiated clearly from other related genera based on the cell-wall peptidoglycan type based on L-Orn-D-Asp (Spring et al., 1996;Shida et al., 1997;Yoon et al., 2001), with the exception of that for H. campisalis, which is based on meso-diaminopimelic acid (Yoon et al., 2007). The aim of the present study was to determine the exact taxonomic status of a halophilic bacterial strain, FP5 T , by using a polyphasic approach, including phenotypic properties, lipid analyses, phylogenetic analysis based on 16S rRNA gene sequences and levels of genotypic relatedness. Strain FP5T was isolated from samples collected during summer 2005 from Fuente de Piedra saline lake, Malaga province, southern Spain (37 u 69 N 4 u 449 W). It was isolated from a saltern crystallizer pond by the dilutionplating technique. Strain FP5T represented the predominant organism in the enrichment and was the only colonyforming organism at the highest dilutions. The enrichment medium (medium A) contained the following componentsThe GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain FP5T is AM295006.A scanning electron micrograph of cells of strain FP5 T and thin-layer chromatographs of total polar lipids of strain FP5T are available as supplementary material with the online version of this paper.