To the best of our knowledge, this is the first study demonstrating the efficiency of Allium sativum hydro-alcoholic extract (ASE) againstFigure growth, biofilm development, and soluble factor production of more than 200 biodeteriogenic microbial strains isolated from cultural heritage objects and buildings. The plant extract composition and antioxidant activities were determined spectrophotometrically and by HPLC–MS. The bioevaluation consisted of the qualitative (adapted diffusion method) and the quantitative evaluation of the inhibitory effect on planktonic growth (microdilution method), biofilm formation (violet crystal microtiter method), and production of microbial enzymes and organic acids. The garlic extract efficiency was correlated with microbial strain taxonomy and isolation source (the fungal strains isolated from paintings and paper and bacteria from wood, paper, and textiles were the most susceptible). The garlic extract contained thiosulfinate (307.66 ± 0.043 µM/g), flavonoids (64.33 ± 7.69 µg QE/g), and polyphenols (0.95 ± 0.011 mg GAE/g) as major compounds and demonstrated the highest efficiency against the Aspergillus versicolor (MIC 3.12–6.25 mg/mL), A. ochraceus (MIC: 3.12 mg/mL), Penicillium expansum (MIC 6.25–12.5 mg/mL), and A. niger (MIC 3.12–50 mg/mL) strains. The extract inhibited the adherence capacity (IIBG% 95.08–44.62%) and the production of cellulase, organic acids, and esterase. This eco-friendly solution shows promising potential for the conservation and safeguarding of tangible cultural heritage, successfully combating the biodeteriogenic microorganisms without undesirable side effects for the natural ecosystems.
Eutrophication of shallow lakes often triggers a series of cascading ecological effects. Among these are shifts in the zooplankton community structure due to phytoplankton changes, or shifts in the fish community reducing size-selective feeding of planktivorous fish. In such conditions larger zooplankton (e.g. Daphnia) can have a selective advantage. Re-oligotrophication can reverse such food web interactions. Europe's largest wetland system (the Danube Delta) went through a period of eutrophication and is now slowly recovering again. However, changes in the Daphnia populations triggered by eutrophication in this system have remained unstudied. We used different sampling strategies to screen 24 lakes (which differ in their ecological state) for the presence of Daphnia as well as for biotic and abiotic parameters potentially explaining Daphnia abundance. Daphnia densities were surprisingly low. We found D. magna ephippia in the sediment, but no D. magna in the water column. Microsatellite analyses on pelagic Daphnia populations confirmed the presence of the Daphnia longispina complex and provided evidence for significant hybridisation events. FluoroProbe data showed that Daphnia was mainly present in lakes with a higher phytoplankton production. Our study provides insights into the spatial and temporal distribution of Daphnia in a very dynamic wetland system.
Danube Delta shallow lakes experience cyanobacteria blooms that can negatively affect the aquatic ecosystem. Although there are several studies on Danube Delta cyanobacteria, little is known about their spatial-temporal patterns and the potential predictive role they can offer.We therefore analyzed the distribution of cyanobacteria in 19 lakes belonging to three lake complexes, and tested whether their seasonal dynamics are in line with the predictions of the PEG model. Furthermore, we investigated to which extent cyanobacteria diversity and abundance were related to lake hydrogeomorphological characteristics such as: surface, water level, connectivity, water retention, flood risk, transparency. Although lakes had different seasonal cyanobacterial assemblages, the biovolume and genus richness had a geographical pattern, decreasing from south-east (lakes forming the fluvial delta) towards north-west (lakes forming the maritime delta). Cyanobacteria biovolume reflected largely the PEG model peaking in summer (the fluvial delta) and autumn ( the maritime delta). Genus richness followed the same pattern. Cyanobacteria distribution was predicted by various abiotic (e.g. risk of flooding, connectivity) and biotic factors (e.g. submersed macrophytes, phytoplankton diversity, peat deposits). Our study contributes to the understanding of cyanobacteria diversity and distribution in shallow interconnected lakes by revealing the complexity of predictors for geographical and seasonal patterns.
Zoosporic parasites (i.e. fungi and fungi-like aquatic microorganisms) constitute important drivers of natural populations, causing severe host mortality. Economic impacts of parasitic diseases are notable in the microalgae biotech industry, affecting production of food ingredients, biofuels, pharma- and nutraceuticals. While scientific research on this topic is gaining traction by increasing studies elucidating the functional role of zoosporic parasites in natural ecosystems, we are currently lacking integrated and interdisciplinary efforts for effectively detecting and controlling parasites in the microalgae industry. To fill this gap we propose to establish an innovative, dynamic European network connecting scientists, industries and stakeholders to optimize information exchange, equalize access to resources and to develop a joint research agenda. ParAqua aims at compiling and making available all information on the occurrence of zoosporic parasites and their relationship with hosts, elucidate drivers and evaluate impacts of parasitism in natural and man-made aquatic environments. We aim to implement new tools for monitoring and prevention of infections, and to create protocols and a Decision Support Tool for detecting and controlling parasites in the microalgae biotech production. Applied knowledge on zoosporic parasites can feed back from industry to ecology, and we therefore will explore whether the developed tools can be applied for monitoring lakes and reservoirs. Short-Term Scientific Missions and Training Schools will be organised specifically for early stage scientists and managers – with a specific focus on ITC – with the aim to share and integrate both scientific and applied expertise and increase exchange between basic and applied researchers and stakeholders.
In this research, potato starch was subjected to physical treatments in order to analyse the changes at the micro- and ultrastructural levels and finally to identify the optimal conditions for disintegrating the starch granules. For the analysis, 10% aqueous solutions of potato starch were treated with a) microwaves; b) heat and c) heat combined with ultrasounds. For each treatment type, the duration was 5 minutes, excepting the microwave treatment, where the time was 1 and 5 minutes; heat power varied from 180W to 900W at the tests with microwave, temperature varied between 65C and 100oC in the thermal experiments and at the thermal analysis combined with ultrasounds temperature had values between 35oC and 85oC. The effect of these treatments was analysed using microscopic techniques (optical and scanning electron microscopy) in order to describe the morphological and micro- and ultrastructural modifications of the starch granules. Results indicated that the morphological and microstructural differences mostly depend on the chosen treatment and on the working conditions. The microwaves treatment was shown to be more effective on disintegrating the starch granule than the thermal action combined with ultrasounds or the thermal treatment alone. Starch granule was cracked at the heat power of 180W even after 1 minute of treatment; after 5 minutes, the gel-like structure was clearly formed for all the granules. Ultrasounds also modified the granule structure by cracking. High temperature (minimal 85oC) was essential for the propagation of ultrasounds or for the thermal treatment in order to assure the efficacy of the physical treatments on the granule. o
This research offers a novel approach for potato wastewater (PW) bioconversion to alcohol by microwaves gelatinization, liquefaction and simultaneous saccharification and fermentation (SSF). Concentrated PW from potato processing to obtain fries was treated by gelatinization, enzymatic hydrolysis through liquefaction and saccharification, and fermentation; a mini-bioreactor was used, with low oxygen, temperature, pH and mixing control. The yeast Saccharomyces cerevisiae and a commercial mix of lactic bacteria were used for fermentations. Two fermentation systems were tested: SSF and saccharification followed by fermentation (SF). The results indicated gelatinization with microwaves at 85 o C for 5 minutes as being very efficient on the starch hydrolysis, compared with the classical thermal gelatinization. SF and SSF cultivation systems showed differences in terms of RS production and consumption and ethanol production; the final values after 48 h of cultivation were around 1% RS (both SF and SSF) and 6% ethanol in SF and 7% ethanol in SSF. Yeast and lactic bacteria were not significantly influencing each other at the cultivation on PW and the lactic bacteria showed no influence on the ethanol production. The most adequate strategy was to cultivate only yeast in SSF system at 35 o C for 36 hours with production of around 7% ethanol with more than 0.5 g ethanol/g RS.
Starch hydrolysates production converts starch to different kinds of products using enzymes in two steps, liquefaction and saccharification. This study investigated three types of analysis methods for the assessing and characterization of the liquefaction process: a rheological method (to measure yield stress), a chemical method (for the determination of Dextrose Equivalent DE) and a chromatographic method (HPLC to obtain the Degrees of Polymerization DPs). Potato starch with 13.5% dry substance was liquefied with the enzyme Liquozyme Supra for two hours in optimal conditions of pH and temperature. A comparative analysis between the methods to describe the liquefaction process was realised. Yield stress offered valuable information on the flow behavior of the samples showing that after 15 minutes of liquefaction the product behaves as a fluid without yield point, with a decreasing value of the middle yield stress. DE had an ascending value during liquefaction indicating that the total reducing sugars are increasing in time. After two hours of liquefaction, glucose (DP1) in very small amounts (around 1%), maltotriose (DP3) and maltotetrose (DP4) in much higher amounts were obtained; no maltose was produced. The quantity of DP3 and DP4 was increasing with the liquefaction time whereas the content in oligosaccharides with DP 5 or higher as 5 (DP5+) was decreasing. The comparative analysis of the chemical and the chromatographic method showed that both methods characterize very well the liquefaction process. It was found that there was a strong relationship between the DE values and the total DP3+DP4 as measured from HPLC and also between DE and DP5+.Â
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