Synthesis, Production, and Biotechnological Applications of Exopolysaccharides and Polyhydroxyalkanoates by Archaea

Extreme environments, generally characterized by atypical temperatures, pH, pressure, salinity, toxicity, and radiation levels, are inhabited by various microorganisms specifically adapted to these particular conditions, called extremophiles. Among these, the microorganisms belonging to the Archaea domain are of significant biotechnological importance as their biopolymers possess unique properties that offer insights into their biology and evolution. Particular attention has been devoted to two main types of biopolymers produced by such peculiar microorganisms, that is, the extracellular polysaccharides (EPSs), considered as a protection against desiccation and predation, and the endocellular polyhydroxyalkanoates (PHAs) that provide an internal reserve of carbon and energy. Here, we report the composition, biosynthesis, and production of EPSs and PHAs by different archaeal species

Recent Advances in the Study of Marine Microbial Biofilm: From the Involvement of Quorum Sensing in Its Production up to Biotechnological Application of the Polysaccharide Fractions

The present review will explore the most relevant findings on marine microbial biofilm, with particular attention towards its polysaccharide fraction, namely exopolysaccharide (EPS). EPSs of microbial origin are ubiquitous in nature, possess unique properties and can be isolated from the bacteria living in a variety of habitats, including fresh water or marine environments, extreme environments or different soil ecosystems. These biopolymers have many application in the field of biotechnology. Several studies showed that the biofilm formation is closely related to quorum sensing (QS) systems, which is a mechanism relying on the production of small molecules defined as "autoinducers" that bacteria release in the surrounding environment where they accumulate. In this review, the involvement of microbial chemical communication, by QS mechanism, in the formation of marine biofilm will also be discussed

Polysaccharides from Wastes of Vegetable Industrial Processing: New Opportunities for Their Eco-Friendly Re-Use

Natural polysaccharides constitute a major group of biopolymers widespread in the whole vegetable kingdom. Plant polysaccharides comprise highly heterogeneous biopolymers that play diverse biological roles as structural elements, energy reserve and biological signalling. Polysaccharides from natural sources have attracted significant interest as biotechnological products, due to their commercial uses in a wide range of industrial applications. Some of them, for example, possess strong antigenic and antipathogenic activities and are successfully employed by the pharmaceutical industry for the formulation of vaccines or as a matrix for drug-delivery applications; others are utilised as food additives taking advantage of their physical-chemical properties (emulsifying power, viscoelasticity, polyelectrolyte, adherence, bio-compatibility, stabilizer, etc). Production of these biopolymers for industrial applications has both economic and environmental costs, depending on the starting materials used as feedstocks and on the chemical/thermal treatments required for their extraction. Recently, wastes from industrial processing of vegetables for food production have been proposed as potential sources of useful polysaccharides. Indeed, transformation and packaging of fruits and vegetables generates huge amounts of wastes, since only a fraction of the incoming biomass is effectively used. The management of such waste biomasses is a problem worldwide, from both economic and environmental standpoints, and therefore research is encouraged to implement new strategies for their re-use. An advantageous option is the extraction of value added chemicals, including different kinds of polysaccharides, besides chemically different species such as polyunsaturated fatty acids, natural pigments, tannins, carotenoids, antioxidants etc. Treatment of vegetable residues by means of newly and environmentally sustainable extraction techniques represents at the moment a fascinating challenge for the valorisation of agro-industrial wastes. Remarkable examples in this framework are represented by polysaccharides isolated from wastes of tomato industrial processing and of tropical fruit juices production based on granadilla, a fruit species of Passiflora, distributed mainly in the warm temperate and tropical regions of America and Africa. These polysaccharides resulted to possess useful biotechnological properties and interesting biological activities. An accurate chemical characterization demonstrated that the main biopolymer obtained from tomato wastes was an heteropolymer with a molecular weight higher than 1 ×106 Da constituted by glucose/ xylose/ galactose/ galactosamine/ glucosamine/ fucose in a relative molar ratio of 1: 0.9: 0.5: 0.4: 0.2: trace, whereas the polysaccharide isolated from waste peels of granadilla (Passiflora liguralis) fruits (with a molecular weight higher than 1 ×106 Da as well) was characterised by the presence of six different sugar residues: xylose/ glucose/ galactose/ galactosamine/ unknown component/ fucose in the relative ratios of 1:0.5:0.2:0.06:0.05:trace. The study of rheological properties showed for both biopolymers an high thermal resistance and an high viscosity, depending, in particular for granadilla waste polysaccharide, on concentration and pH, with a maximum value of 1.4  at a concentration of 3% in distilled water and a maximum value of 7.0  in citrate buffer solution. The main point of interest was represented by their suitability to produce elastic and biodegradable films potentially useful in agriculture for mulching applications in fields protection. Further studies were performed to evaluate the biological activity of these biopolymers. Tomato waste polysaccharides resulted to inhibit NF-κB activation and iNOS gene expression in J774 macrophages by preventing the reactive species production, thus suggesting a key role of these compounds in controlling oxidative stress and/or inflammation. Biological activity of polysaccharides from granadilla peels was assessed by means of brine shrimp bioassay: the isolated compound was able to strongly inhibit the cytotoxic effects produced by avarol, whose LD50 was increased of about 10-fold with respect to the control in the absence of polysaccharide. More recent studies have been focused on lemon wastes. Citrus processing produces a considerable amount of waste biomass called “lemon pomace” consisting of peels (flavedo and albedo), pulp and seeds, mainly composed by water, soluble sugars and fibres, together with other compounds such as oils, flavonoids and vitamins. Lemon wastes, generated in huge amounts by Italian industries for “Limoncello” liquor production, have been treated in order to separate useful polysaccharides. A major polysaccharide fraction was isolated and purified: analysis by means of gel filtration allowed to determine a molecular weight higher than 1 ×106 Da. The sugar components were identified after acid hydrolysis, by means of TLC and HPAE-PAD chromatography: the main components resulted to be galactose, galacturonic acid and arabinose. Further studies are now being implemented to study both rheological properties and biological activity of lemon polysaccharides. In conclusion, polysaccharides are among the most interesting biopolymers that can be recovered from vegetables: the use of wastes from industrial processing of different vegetables together with eco-friendly extraction techniques allowed the isolation of remarkable polysaccharides. Some of them showed to possess interesting rheological properties, potential biotechnological applications and finally promising bioactivities as potential anti-inflammatory agents, as tested in different biological model systems

Exploring Marine Environments for the Identification of Extremophiles and Their Enzymes for Sustainable and Green Bioprocesses

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

Year-round under-ice research on MOSAiC using a remotely operated vehicle

To provide easy and reliable access to the underside of the sea-ice during the MOSAiC expedition, the Alfred-Wegener-Institute will operate its new remotely operated vehicle during the full duration of the drift directly from an access hole on the ice. The vehicle has proven its capabilities during several Arctic field campaigns and provides a stable sensor platform, as well as inspection and intervention capabilities. It has a maximum range of 300m from the designated access hole(s) and a depth rating of 100m. The ROV operations under sea ice will allow repeat measurements during the entire drift with little impact to the sea ice, the upper ocean, the ecosystem and other objects of interest. In the current setup, the vehicle comprises various video cameras, a still camera, single and multibeam bathymetric sonar, scanning sonar, a CTD, triplet fluorometer as well as sensors for hyperspectral irradiance, radiance, extinction, dissolved oxygen, pH and nitrate. The vehicle position is recorded by acoustic positioning tied into the floe fixed reference frame of all observations on the central observatory floe. Beyond this, the vehicle also provides several additional power outlets and data ports that allow connecting additional systems to the vehicle. Currently, the integration of a current profiler (ADCP), a zooplankton camera, different nets for zooplankton sampling, as well as a water sampling system are under development. All data are recorded, timestamped on site, and will be uploaded to an open data portal, which will be easily accessible for the scientific community. The main task of the vehicle will be repeated mapping of the spatial variability of the various parameters on a weekly basis. In addition, we plan to use it for deployment and retrieval of under-ice sensor packages and perform inspection and manipulation tasks. The ROV operations can easily be conducted by a small on-board sea-ice team due to the reliable and redundant system architecture. Altogether, measurements give a comprehensive picture of the spatio-temporal evolution of the sea-ice and its associated ecosystem. They link upper ocean dynamics with the thermodynamic and dynamic development of the ice cover. In combination with surface measurements, like aerial photography and terrestrial laser scanning, a full 3D characterization of the local ice cover will enable areal upscaling of the obtained results also using remote sensing data. Ideally these high resolution measurements at the MOSAiC central observatory will be extended with regular missions of an autonomous underwater vehicle (AUV), which can travel longer distances in spite of a small logistical footprint, to tie the local observations into the context of the larger spatial scale of the MOSAiC distributed measurement network

Evaluation of heavy metals, cytotoxicity, and antioxidant activity of tomatoes grown in toxic muddy soils

This research studies tomatoes grown in polluted soils to ascertain their phytochemical and nutritive features. Pulp and seeds from tomatoes grown in muddy soils were analyzed for their antioxidant power and their toxicity because of the possibility that heavy metals were present in the soils. An antioxidant assay on methanol extracts was made by using DDPH, while an ABTS [2,2'-Azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid)] assay was used to evaluate the antioxidant activity of lipophilic fractions. Results of the antioxidant assay showed that the tomatoes maintained a high level of antioxidant activity especially in the lipophilic fractions which contain the most representative compounds. Cytotoxic activity was performed on HeLa, PDAC, and A375 cell lines by [3-(4,5-dimethylthiazol-2-yl)-2,5-phenyl-2H-tetrazolium bromide] (MTT) assay. Results showed that neither the seeds, nor the pulp, of the extracts was cytotoxic. The presence of heavy metals was evaluated by using spectroscopy of atomic absorption with a graphite oven. Test results show the absence of heavy metals and these results have an interesting scientific role because they provide useful information for promoting food safety

Bioprospecting of exopolysaccharide-producing bacteria from different natural ecosystems for biopolymer synthesis from vinasse

Abstract Background Exopolysaccharides (EPSs) belong to a family of organic thickeners or alternative hydrocolloids of microbial origin. Because the chemical structure offers beneficial bioactive functions, biocompatibility and biodegradability, EPSs are used in the chemical, food, pharmaceutical, cosmetics, and packaging industries as well as in agriculture and medicine. In this study, new bacterial strains were selected on the basis of their ability to synthesize EPS from substrate containing vinasse as a nutrient source to identify the best candidate for bio-based polymer production. Results Among the 99 newly identified bacterial strains isolated from different natural ecosystem, the strain Azotobacter chroococcum 76A was selected as the best biopolymer producer since it synthesized the highest concentration of EPS in all media containing vinasse. The maximum EPS concentration (44.6 ± 0.63 mg/50 mL) was observed at 24 h, corresponding to its sub-stationary growth phase (7 × 108 ± 0.29 CFU/mL). Chemical characterization of the EPS produced showed that carbohydrates representing the principal component, followed by uronic acids and proteins. Interestingly, comparing the IR spectrum of the EPS with alginate by FTIR-ATR analysis revealed an overlap of a peak identified as guluronic acid, a component of alginate. Conclusions The potential biotechnological capacity of A. chroococcum 76A to synthetize biopolymer from vinasse, inexpensive starting materials, represents a possible alternative to expensive disposal of agri-food waste through its transformation into high value-added products

Evaluation of hourly S02- and NOx-emissions in Baden-Württemberg in a spatial resolution of 1 x 1 km for the period of the TULLA-measuring-campaign

Ziel des in diesem Bericht beschriebenen Vorhabens ist die Ermittlung stündlicher Emissionen für Baden-Württemberg in einem Raster von 1 * 1 km-Elementen für 12 Tage im März 1985 während der sogenannten TULLA-Meßkampagne. Erfaßt werden hierbei die Schadstoffe S02 und NOx. Für die verschiedenen Sektoren werden verschiedene Methoden der Schadstofferfassung angewandt: Für öffentliche Wärmekraftwerke und andere Großemittenten mit einer Feuerungsleistung über 10 HW wird eine Umfrageaktion durchgeführt. Diese umfaßt etwa 330 Betreiber von Feuerungsanlagen. Für die restlichen Feuerungsanlagen einschließlich der privaten Haushalte und für den Kraftfahrzeugsektor werden Modelle entwickelt, die aufgrund von Gebäudestrukturdaten, Jahresenergieverbräuchen der Industrie, Außentemperaturen, Konjunkturverläufen etc. den zeitlichen und räumlichen Verlauf der Emissionen bestimmen.The aim of this study was to establish an emission inventory of S02 and NOx for the state of Baden-Württemberg for the period of the TULLA-Experiment. The emissions were calculated for every hour during this period and in the scale of 1 * 1 kilometer. Different methods to evaluate the emissions were applied : All power-plants and other major emittents (mainly of the industry-sector) with furnaces greater 10 HW were asked to give the amount of hourly emissions directly, or if not possible, the hourly energy consumption. In this campaign about 330 plants were included. For all other emittents including private households and the transportation-sector models were developed to calculate the time-dependent emissions based on exogeneous parameters such as housing-data, yearly energy-consumption-data, temperature, economic data etc

High resolution emission inventory of S02 and NOx emissions in Baden-Württemberg during the TULLA - measurement campaign

Im Rahmen dieses Projekts wird ein Emissionskataster für Baden-Württemberg in einer Auflösung von 1 mal 1 Kilometer für die Zeit der TULLA-Meßkampagne erstellt. Erfaßt werden hierbei die Schadstoffe S02 und NOx. Für die verschiedenen Sektoren werden verschiedene Methoden der Schadstofferfassung angewandt: Für öffentliche Kraftwerke und andere Großemittenten mit einer Feuerungsleistung über 10 MW wurde eine Umfrageaktion durchgeführt. Diese umfaßt etwa 360 Betreiber von Feuerungsanlagen.. Für die restlichen Feuerungsanlagen einschließlich der privaten Haushalte und für den Kraftfahrzeugsektor wurden Modelle entwickelt, die aufgrund äußerer Parameter wie Gebäudestrukturen, Jahresenergieverbrauche der Industrie, Außentemperatur, Konjunkturverlauf etc. den zeitlichen und räumlichen Verlauf der Emissionen bestimmen. Die Modellberechnungen werden zur Zeit durchgeführt. Erste Ergebnisse, die in diesem Bericht dargestellt werden, zeigen insbesondere die räumlichen und zeitlichen Schwankungen der S02- und NOx-Emissionen in Baden-Württemberg auf.The aim of this study is to determine the amount of emissions of S02 and NOx for the state of Baden-Württembery during the period of the TULLA-experiment. The emissions are calculated for every hour during this period and in the scale of 1 x 1 Kilometer. There are different methods used to determine the emissions. All power-plants and other major sources (mainly of the industry-sector) with furnaces greater 10 MW were asked to give the amount of hourly emissions directly, or if not possible, the hourly energy consumption. In this campaign about 360 institutions and plants were included. For all other emittents including private households and the transportation sector, models were developed to calculate the timedependent emissions based on exogeneous parameters such as housingdata, yearly energy-consumption-data, temperature, economic situation etc. The model-calculations are executed right now, preliminary results show the time-dependent and geographical variations of the emissions for Baden-Württemberg

Ermittlung von stündlichen SO2- und NOx-Emissionen in Baden-Württemberg in kleinräumiger Auflösung

Berichtet wird über die Ermittlung der SO2- und NOx-Emissionen aus der TULLA-Meßkampagne im März 1985 mit Hilfe speziell entwickelter Methoden und Modelle. Dargestellt und diskutiert werden die stündlichen Emissionen für ein Raster mit 1 km x 1 km Flächenquadrate. Die so ermittelten - auch nach Quellhöhe differenzierten - Emissionsraten stehen für weitere Auswertungen und vor allem als Grundlage für räumlich/zeitlich entsprechend aggregierte Emissionsprognosen sowie realitätsbezogene Emissionsszenarien zur Verfügung. Die Daten sollen als Input für ein an der Universität Karlsruhe entwickeltes Ausbreitungsmodell herangezogen werden