Search

BACKGROUND: Purple Queen® is an early ripening pomegranate cultivar growing well in soilless cultivation. Substrates have direct effects on plant development and, due to progressive peatland exhaustion, the request for new materials for plant growth is high. OBJECTIVE: The objective of this work was to verify the effects of a new potential substrate obtained from the remediation of marine port sediments on the nutraceutical profile of Purple Queen® fruits, using 50% and 100% of reclaimed sediment. METHODS: The study was carried out determining ellagitannins and polysaccharides obtained from peel after decoction, and anthocyanins in aril juice on fruits from two agronomic seasons. RESULTS: The presence of 100% of the sediment had a partial detrimental effect on fruits size and weight. Compared to a peat-based commercial substrate (control), remediated sediment preserved ellagitannin content and increased the anthocyanin amount (up to 40% higher) and polysaccharide content up to 34% on dry fruit. High molecular weight polysaccharides (>2000 kDa) were identified in all the fruits with glucose and galacturonic acid as the major sugars. CONCLUSIONS: Fruits from plants cultivated only on sediment or in a mixture with 50% of peat showed significant increases of bioactive compounds as stress response in two consecutive seasons.

The induction of biocrusts through inoculation-based techniques has gained increasing scientific attention in the last 2 decades due to its potential to address issues related to soil degradation and desertification. The technology has shown the most rapid advances in the use of biocrust organisms, particularly cyanobacteria and mosses, as inoculants and biocrust initiators. Cyanobacteria and mosses are poikilohydric organisms – i.e., desiccation-tolerant organisms capable of reactivating their metabolism upon rehydration – that can settle on bare soils in abiotically stressing habitats, provided that selected species are used and an appropriate and customized protocol is applied. The success of inoculation of cyanobacteria and mosses depends on the inoculant's physiology, but also on the ability of the practitioner to identify and control, with appropriate technical approaches in each case study, those environmental factors that most influence the inoculant settlement and its ability to develop biocrusts. This review illustrates the current knowledge and results of biocrust induction biotechnologies that use cyanobacteria or mosses as inoculants. At the same time, this review's purpose is to highlight the current technological gaps that hinder an efficient application of the technology in the field.

The extracellular polysaccharides produced by cyanobacteria have distinctive characteristics that make them promising for applications ranging from bioremediation to biomedicine. In this study, a sulfated polysaccharide produced by a marine cyanobacterial strain and named cyanoflan was characterized in terms of morphology, chemical composition, and rheological and emulsifying properties. Cyanoflan has a 71 % carbohydrate content, with 11 % of sulfated residues, while the protein account for 4 % of dry weight. The glycosidic-substitution analysis revealed a highly branched complex chemical structure with a large number of sugar residues. The cyanoflan high molecular mass fractions (above 1 MDa) and entangled structure is consistent with its high apparent viscosity in aqueous solutions and high emulsifying activity. It showed to be a typical non-Newtonian fluid with pseudoplastic behavior. Altogether, these results confirm that cyanoflan is a versatile carbohydrate polymer that can be used in different biotechnological applications, such as emulsifying/thickening agent in food or cosmetic industries. published

Nowadays commercial preparations of yeast polysaccharides (PSs), in particular mannoproteins, are widely used for wine colloidal and tartrate salt stabilization. In this context, the industry has developed different processes for the isolation and purification of PSs from the cell wall of Saccharomyces cerevisiae. This yeast releases limited amounts of mannoproteins in the growth medium, thus making their direct isolation from the culture broth not economically feasible. On the contrary, Schizosaccharomyces japonicus, a non-Saccharomyces yeast isolated from wine, releases significant amounts of PSs during the alcoholic fermentation. In the present work, PSs released by Sch. japonicus were recovered from the growth medium by ultrafiltration and their impact on the wine colloidal stability was evaluated. Interestingly, these PSs contribute positively to the wine protein stability. The visible haziness of the heat-treated wine decreases as the concentration of added PSs increases. SDS-PAGE Gel electrophoresis results of the haze and of the supernatant after the heat stability test are consistent with the turbidity measurements. Moreover, particle size distributions of the heat-treated wines, as obtained by Dynamic Light Scattering (DLS), show a reduction in the average dimension of the protein aggregates as the concentration of added PSs increases.

Cyanobacteria are widespread prokaryotic organisms that represent feasible biotechnological tools to set up valid approaches to counteract desertification. Their peculiar physiological traits, and their resilience to abiotic stresses, allow their application on abiotically constrained soils to trigger their stabilization. A successful cyanobacteria inoculation results in the formation of cyanobacterial biocrusts, complex microbial communities characterized by tangled filament meshes imbued in a matrix of self-secreted extracellular polysaccharides (EPS) that keep loose sediments and aggregates firmly in place. However, the capability to form stable cyanobacterial biocrusts is not common to all the species, and a mix of factors can hamper the process, notably inoculum amount, and substrate characteristics. The aim of this work was to assess the influence of inoculum quantity and substrate granulometry on the physical stability of cyanobacterial biocrusts induced by inoculating the strain Leptolyngbya ohadii in a microcosm experiment, under laboratory conditions. After applying three different initial inoculum amounts on two different sand granulometries (medium and coarse sand), we assayed aggregate stability, physical stability and surface hydrophobicity on the resulting biocrusts during a 30-day incubation. Also, the features and the role of the EPS synthesized by L. ohadii were studied following their isolation, characterization, and direct application on the sand. The two EPS fractions produced by the strain, one more soluble and easily released in the surrounding medium (released polysaccharides, RPS) and one solidly attached to the filaments (glycocalyx EPS, G-EPS), were separately tested. Cyanobacterial biocrusts visibly formed in all the microcosms after 15 days. However, we observed a strong effect of sand granulometry in affecting aggregate stability and tensile strength, both of which appeared weaker on coarse sand. A higher amount of initial inoculum was necessary to produce stable biocrusts on coarse sand compared to medium sand. Also, we observed how the inoculation of EPS alone did not sort most of the significant effects that we detected by inoculating the whole culture, pointing at the importance of the action of the cyanobacterial filaments in soil conglomeration. However, a significant increase in physical stability was achieved by inoculating G-EPS on medium sand, suggesting the involvement of this fraction in biocrusts structuration. This work analyzes for the first time the effects of the variable grain size and inoculum amount in the achievement of physically stable biocrusts by cyanobacteria inoculation. The results that we obtained are useful in improving and optimizing the process of biomass preparation and dispersion for future indoor and outdoor studies.

Aim of this study was to evaluate the suitability of ensiled giant reed, ensiled maize, ensiled olive pomace, wheat bran for combined systems (CS: dark fermentation + anaerobic digestion (AD)) producing hydrogen-rich biogas (biohythane), tested in batch under basic operational conditions (mesophilic temperatures, no pH control). Substrates were also analyzed under a single stage AD batch test, in order to investigate the effects of DF on estimated energy recovery (ER) in combined systems. In CS, maize and wheat bran exhibited the highest hydrogen potential (13.8 and 18.9 NL kgVS (1)) and wheat bran the highest methane potential (243.5 NL kgVS (1)). In one-stage AD, giant reed, maize and wheat bran showed the highest methane production (239.5, 267.3 and 260.0 NL kgVS (1)). Butyrate/acetate ratio properly described the dark fermentation, correlating with hydrogen production (r = 0.92). Wheat bran proved to be a promising residue for CS in terms of hydrogen/methane potential and ER. (C) 2016 Elsevier Ltd. All rights reserved.

Biological Soil Crusts (BSCs) represent an important part of the living cover in drylands worldwide. BCSs change soil hydrology due to extracellular polymeric substances (EPS)-excreting species of cyanobacteria, dominant members of dryland-BSCs. The presence of EPS allowed matric potential (Ψm) to remain unchanged down to 20% water content, whereas, without EPS, Ψm started decreasing at 80% water content. The EPS matrix improved the water retaining capacity of soil, suggesting that BSCs would delay onset of restrictive matric potential values due to its larger water holding capacity.

Hydrogen represents a possible alternative energy carrier to face the growing request for energy and the shortage of fossil fuels. Photofermentation for the production of H2 constitutes a promising way for integrating the production of energy with waste treatments. Many wastes are characterized by high salinity, and polluted seawater can as well be considered as a substrate. Moreover, the application of seawater for bacterial culturing is considered cost-effective. The aims of this study were to assess the capability of the metabolically versatile freshwater Rhodopseudomonas palustris 42OL of producing hydrogen on salt-containing substrates and to investigate its salt stress response strategy, never described before. R. palustris 42OL was able to produce hydrogen in media containing up to 3 % added salt concentration and to grow in media containing up to 4.5 % salinity without the addition of exogenous osmoprotectants. While the hydrogen production performances in absence of sea salts were higher than in their presence, there was no significant difference in performances between 1 and 2 % of added sea salts. Nitrogenase expression levels indicated that the enzyme was not directly inhibited during salt stress, but a regulation of its expression may have occurred in response to salt concentration increase. During cell growth and hydrogen production in the presence of salts, trehalose was accumulated as a compatible solute; it protected the enzymatic functionality against salt stress, thus allowing hydrogen production. The possibility of producing hydrogen on salt-containing substrates widens the range of wastes that can be efficiently used in production processes.

Aims Aim of the paper was to assess the feasibility of producing hydrogen as a biofuel by photofermentation of fermented water lettuce (Pistia stratiotes L.) waste biomass, after a nitrogen-stripping treatment. Methods and Results A natural (42OL) and an engineered strain (CGA676, with low-ammonium sensitivity) of Rhodopseudomonas palustris were used for producing hydrogen. The stripping procedure was highly effective for ammonium removal, with an acceptable selectivity (91% of ammonium was removed; only 14% of total organic acids were lost). Both strains were able to produce hydrogen only in the nitrogen-stripped substrate. The natural strain R.palustris 42OL showed a higher Biochemical Hydrogen Potential (1224 mL L−1 vs 720 mL L−1; 50.0 mol m−3 vs 29.4 mol m−3), but at a lower rate (5.6 mL L−1 h−1 vs 7.3 mL L−1 h−1; 0.23 mol m−3 h−1 vs 0.29 mol m−3 h−1) than strain CGA676. Conclusions Water lettuce waste biomass can be used for biofuel production, after hydrolization, fermentation and nitrogen stripping. Impact of the study The investigation on novel, low cost and sustainable biomasses as feedstocks for biofuel production is a priority. Aquatic plants do not compete for arable land. Moreover, water lettuce is a floating and invasive weed, thus its biomass must be harvested when detrimental, and can now be biotransformed in clean hydrogen. This article is protected by copyright. All rights reserved.

Polylactic acid (PLA), a bioplastic synthesized from lactic acid, has a broad range of applications owing to its excellent proprieties such as a high melting point, good mechanical strength, transparency, and ease of fabrication. However, the safe disposal of PLA is an emerging environmental problem: it resists microbial attack in environmental conditions, and the frequency of PLA-degrading microorganisms in soil is very low. To date, a limited number of PLA-degrading bacteria have been isolated, and most are actinomycetes. In this work, a method for the selection of rare actinomycetes with extracellular proteolytic activity was established, and the technique was used to isolate four mesophilic actinomycetes with the ability to degrade emulsified PLA in agar plates. All four strains&mdash, designated SO1.1, SO1.2, SNC, and SST&mdash, belong to the genus Amycolatopsis. The PLA-degrading capability of the four strains was investigated by testing their ability to assimilate lactic acid, fragment PLA polymers, and deteriorate PLA films. The strain SNC was the best PLA degrader&mdash, it was able to assimilate lactic acid, constitutively cleave PLA, and form a thick and widespread biofilm on PLA film. The activity of this strain extensively eroded the polymer, leading to a weight loss of 36% in one month in mesophilic conditions.

The ability of Rhodopseudomonas palustris cells to rapidly acclimate to high light irradiance is an essential issue when cells are grown under sunlight. The aim of this study was to investigate the photo-acclimation process in Rhodopseudomonas palustris 42OL under different culturing conditions: (i) anaerobic (AnG), (ii) aerobic (AG), and (iii) under H2-producing (HP) conditions both at low (LL) and high light (HL) irradiances. The results obtained clearly showed that the photosynthetic unit was significantly affected by the light irradiance at which Rp. palustris 42OL was grown. The synthesis of carotenoids was affected by both illumination and culturing conditions. At LL, lycopene was the main carotenoid synthetized under all conditions tested, while at HL under HP conditions, it resulted the predominant carotenoid. Oppositely, under AnG and AG at HL, rhodovibrin was the major carotenoid detected. The increase in light intensity produced a deeper variation in light-harvesting complexes (LHC) ratio. These findings are important for understanding the ecological distribution of PNSB in natural environments, mostly characterized by high light intensities, and for its growth outdoors.

The main crude polysaccharides (CPS), extracted from two widely cultivated pomegranate varieties, Laffan and Wonderful, were studied and characterized. We obtained the highest CPS extraction yield (approximatively 10% w/w on dried matter) by 1h of decoction (ratio 1/40w/v). The predominant polymers (75–80%) of the CPS samples showed a hydrodynamic volume close to 2000kDa by size exclusion chromatography and the exocarp and mesocarp profiles were very similar. The proton spectra (1H NMR), according to sugar composition and gelling ability, confirmed the main polysaccharide fractions were pectin with different acylation and methylation degree. The CPS from Laffan and Wonderful mesocarp showed prebiotic properties in vitro with Lactobacillus and Bifidobacterium strains. The composition of the decoction (12% ellagitannins and 10% of CPS) obtained by a green extraction process of pomegranate by-products, makes it a suitable component of functional food formulations.

The present study was aimed at assessing the biotransformation of dark fermented agroindustrial residues and energy crops for the production of hydrogen and poly-β-hydroxybutyrate (PHB), in lab-scale photofermentation. The investigation on novel substrates for photofermentation is needed in order to enlarge the range of sustainable feedstocks. Dark fermentation effluents of ensiled maize, ensiled giant reed, ensiled olive pomace, and wheat bran were inoculated with Rhodopseudomonas palustris CGA676, a mutant strain suitable for hydrogen production in ammonium-rich media. The highest hydrogen producing performances were observed in wheat bran and maize effluents (648.6 and 320.3mLL(-1), respectively), both characterized by high initial volatile fatty acids (VFAs) concentrations. Giant reed and olive pomace effluents led to poor hydrogen production due to low initial VFAs concentrations, as the original substrates are rich in fiber. The highest PHB content was accumulated in olive pomace effluent (11.53%TS), ascribable to magnesium deficiency.