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To optimise fight against bacterial infections in oral cavity, this study investigates photodynamic inactivation of clinical and reference strains of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia which were treated with 6 µM of four Zn phthalocyanines (ZnPc 1-4) and exposed to laser (35 mW/cm²) and 665 nm for 5, 12 and 20 min. Complete inactivation was obtained with clinical strains P. gingivalis treated with ZnPc1 and ZnPc2 and clinical strain P. intermedia, treated with ZnPc1 and ZnPc4 at any light dose, the reference strain P. intermedia, treated with ZnPc1 at light dose of 23 J/cm² and 38.4 J/cm² and ZnPc2 at light dose of 38,4 J/cm². Highest bacterial reduction - four to five log, depending on exposure time for the reference strain P. gingivalis, was achieved when ZnPc2 was applied. Weakest effect was observed in the clinical and reference strain A. actinomycetemcomitans - only 2 log decrease in microbial count when treated with ZnPc4 and exposed 12 min and more and about 3 log reduction, when treated with ZnPc3 and ZnPc4 at light dose of 38.4 J/cm², respectively. Photodynamic effect appeared to be dependant on chemical structure of phthalocyanines, microbial species and strain and light dose. [ABSTRACT FROM AUTHOR]

The bioremediation of digestate using microalgae is perspective solution to decreasing the eutrophication from organic waste. Cultivation of microalgae in waste anaerobic residue leads to a reduction in production costs of valuable bioactive metabolites. The red microalga Porphyridium cruentum is a representative of Rhodophyta, which is a producer of many useful bioproducts. The present study aimed to determine how the biochemical characteristics change when this microalga was grown in two undiluted digestates obtained as by-products of the anaerobic biodegradation at 35°C and 55°C of wheat straw, as a renewable source for biogas production. The results showed that the growth of the control was comparable to that in the thermophilic digestate, but the biochemical characteristics of the three variants (control, termophilic digestate, mesophilic digestate) were quite different. Accumulation of proteins and lipids is significantly higher in the algae cultivated in digestates (over 1.1 times for thermophilic variant), while carbohydrates reached 51% in the control, 41% in the thermophilic digestate and 38% in the mesophilic one, respectively. In conclusion: Porphyridium cruentum grew well in thermophilic digestate. The strain could be used simultaneously for bioremediation of agricultural waste as well as for the production of valuable lipids and proteins. [ABSTRACT FROM AUTHOR]

Research on the biological activities and applications of polysaccharides as active biocompounds synthesised by marine unicellular algae, which are, in many cases, released to the surrounding environment - exopolysaccharides, has revealed the possibility of many applications. We have investigated the growth and development of two red microalgae Porphyridium cruentum and Rhodella reticulata, where the used medium was decolourised with active carbon digestate from anaerobic digestion of agricultural waste - wheat straw. The biomass accumulation for both strains reached a dry weight of 5.2 to 5.5±0.2 mg ml-1, starting from 0.85 mg ml-1 m initial concentration for 6 days. Production of heteropolysaccharides was estimated to show increased yield of 0.35 mg ml-1 on the 6th day of cultivation for the Rhodella reticulata and 0.28 mg ml-1 for Porphyridium cruentum, compared to 0.25 mg ml-1 of the control - growth in a standard medium. The two isolated bioactive substances were then tested using 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulphophenyl)-2Htetrazolium, inner salt - (MTS test), as potential antitumor agents on two cancer cell lines and a normal one to establish diminishing of cell vitality, mostly when applied to the high metastatic cell line MDA-MB 231-47%, when electroporation was applied by the heteropolysaccharide synthesised by the Porphyridium cruentum, grown in digestate. [ABSTRACT FROM AUTHOR]

Green microalgae are widely known for their nutritional and therapeutic applications due to the richness in nutrients and bioactive elements. The aim of this research was to characterise the phytochemical and nutritional compounds with antioxidant properties of three different strains: Chlorella vulgaris R-06/2; Scenedesmus acutus M Tomaselli 8 and Scenedesmus obliquus BGP under optimal growth conditions. Algal concentration was measured daily by dry weight. The concentration of phytochemical compounds was determined by using UV-vis. spectrophotometry. The highest biomass yield was achieved by Scenedesmus obliquus BGP-(6.6 g/l) after 144 h of cultivation. In the experiments Scenedesmus acutus accumulated the highest percentage of pigments (3.22% of dry weight). The polyphenols produced by the Scenedesmus sp. representatives does not impact much the level of the antioxidant activity, at the same time, Ch. vulgaris shows much higher levels of polyphenols and ferric reducing ability of plasma (FRAP), which makes it the alga with the best antioxidant properties from the assessed ones. This work proved the presence of biologically active substances in the three strains studied. [ABSTRACT FROM AUTHOR]

The impact of various stress factors on the same organisms isolated from different climatic zones is an interesting and little-studied topic. In the present work, the effects of the biocide Sanosil on antarctic and mesophilic isolates of the green alga Chlorella vulgaris was estimated. The concentration of 0.15% was found to have an algicidal effect. Changes in the content of photosynthetic pigments, total proteins and total carbohydrates at different concentrations lower than the algicidal were studied. The influence on growth and viability of the algal strains was studied. The results showed a significant inhibition of the biomass accumulation in both isolates with increasing the concentration of Sanosil. However, slight growth stimulation in the Chlorella vulgaris antarctic isolate was observed upon treatment with the lowest concentrations of Sanosil (0.01 and 0.03%). This result was in correlation with the viability test. In the mesophilic isolate, the amount of chlorophyll a and b decreased smoothly after exposure to increasing Sanosil concentrations, while the percent of carotenoids slightly increased at the lowest concentrations applied. In the antarctic isolate there was a slight increase in the quantity of chlorophyll a and b together with a significant increase of carotenoids content at the lowest biocide concentrations. Application of Sanosil at concentrations higher than 0.03% led to a gradual but significant decrease in pigment content in both isolates. In the mesophilic isolate treated with the lowest concentrations of Sanosil, there was no change in the total protein content, while the amount of carbohydrates was increased by about 8%. However, the same concentrations of Sanosil led to a slight increase in the quantity of total proteins and a decrease in the carbohydrates content in the antarctic isolate. As a result of Sanosil action at concentrations higher than 0.03%, a decrease in the amount of proteins and carbohydrates was observed in both isolates which was most pronounced at the highest concentration applied (0.1%). [ABSTRACT FROM AUTHOR]

In the present work the research and results on sol-gel synthesis and structure of hybrid nanocomposites is described and discussed. Four different types of silicon precursors have been used: tetraethylorthosilicate (TEOS), tetramethylorthosilicate (TMOS), methyltriethoxysilicate (MTES) and ethyltrimethoxysilicate (ETMS). The hybrids have been prepared at room temperature by replacing different quantities of the inorganic precursor with an organic component; polyacrilamide gel (PAAG). The structure of the hybrid nanocomposites obtained has been studied by infrared spectroscopy, XRD, NMR, AFM, BET, and SEM. All samples were amorphous and contained pores with average diameter about 1-1.6 nm. The surface structure of the hybrids has been observed by SEM. Bands at 1080, 790 and 480 cm-1 were observed in the infrared spectra of all studied samples. They are assigned to the vas, Vs and δSi-O-Si vibrational modes, although these bands can also be related to the presence of Si-O-C, C-O-C and Si-C bonds. A self organised nanostructure has been observed by AFM. In the resulting hybrids the nano-building blocks are made up of units 30 nm in size. These nanocomposites were used as carriers for cell immobilisation. [ABSTRACT FROM AUTHOR]

Anaerobic co-digestion of waste wheat straw and horse manure in two steps was revealed as a promising option for renewable energy production in the form of hydrogen and methane. Addition of waste cooking oils, disposal of which could cause damage to health or the environment, as a third substrate for digestion, is suggested as an approach not only to help handle the increasing volume of food waste worldwide but also to improve process performance. In the present study, waste cooking oil, in a concentration of 5%, appeared to be a positive modulator of anaerobic digestion with the production of hydrogen and did not lead to inhibition of the hydrolysis phase. The overall efficiency of the two-stage anaerobic digestion of the mixture, which contains mainly lignocellulose waste, is positively dependent on thermochemical pretreatment with the alkali reagent (Ca(OH) 2 ), but elevated temperature (55 °C) and cooking oil addition revealed the opportunity to omit the pre-treatment step. Nevertheless, the overall energy production was lower due to the methane production step. However, the addition of waste cooking oils to the process in which lig-nocellulose is not pretreated (V3) led to an increase in the methane production and energy yield compared to V1. The anaerobic digestion of lignocellulosic waste is a complex process and comprises successive degradation pathways and syntrophic microbial associations' activities, so the division in two reactors ensured suitable conditions for the microorganisms residing in each of them. In this study, along with the production of hydrogen and methane and the separation of the hydrolysis and methanogenesis stages, utilization of agriculture- and kitchen-generated wastes was realized in the context of waste-to-energy sustainable production methods.

The main purpose of this study was to identify the microbial communities (bacterial, archaeal and fungal) in a two-stage system of anaerobic bioreactors for the production of hydrogen and methane from the waste substrate-corn steep liquor. Wastes from the food industry are valuable resources with potential in biotechnological production because of their high organic matter contents. In addition, the production of hydrogen and methane, volatile fatty acids, reducing sugars and cellulose content was monitored. Two-stage anaerobic biodegradation processes were performed by microbial populations in the first hydrogen generating bioreactor (working volume of 3 dm 3 ) and in the second methane-generating reactor (working volume of 15 dm 3 ). Cumulative hydrogen yield reached 2000 cm 3 or 670 cm 3 /L a day, while the methane production reached a maximum quantity of 3300 cm 3 or 220 cm 3 /L a day. Microbial consortia in anaerobic digestion systems play an essential role for process optimization and biofuel production enhancement. The obtained results showed the possibility of conducting two separate processes-the hydrogenic (hydrolysis and acidogenesis) and methanogenic (acetogenesis and methanogenesis)-as two stages of anaerobic digestion to favor energy production under controlled conditions with corn steep liquor. The diversity of microorganisms as main participants in the processes in the bioreactors of the two-stage system was followed using metagenome sequencing and bioinformatics analysis. The obtained metagenomic data showed that the most abundant phylum in both bacterial communities was Firmicutes -58.61% and 36.49% in bioreactors 1 and 2, respectively. Phylum Actinobacteria were found in significant quantities (22.91%) in the microbial community in Bioreactor 1, whereas in Bioreactor 2, they were 2.1%. Bacteroidetes are present in both bioreactors. Phylum Euryarchaeota made up 0.4% of the contents in the first bioreactor and 11.4% in the second. As the dominant genera among methanogenic archaea are Methanothrix (8.03%) and Methanosarcina (3.39%), the main fungal representatives were Saccharomyces cerevisiae . New knowledge of anaerobic digestion mediated by novel microbial consortia could be widely used to convert different wastes to green energy.

Anaerobic digestion (AD) is a widespread biological process treating organic waste for green energy production. In this study, wheat straw and corn stalks without any harsh preliminary treatment were collected as a renewable source to be employed in a laboratory-scale digester to produce biogas/biomethane. Processes parameters of temperature, pH, total solids, volatile solid, concentration of volatile fatty acids (VFA), and cellulose concentration, were followed. The volume of biogas produced was measured. The impact of organic loading was stated, showing that the process at 55 °C tolerated a higher substrate load, up to 45 g/L. Further substrate increase did not lead to biogas accumulation increase, probably due to inhibition or mass transfer limitations. After a 12-day anaerobic digestion process, cumulative volumes of biogas yields were 4.78 L for 1 L of the bioreactor working volume with substrate loading 30 g/L of wheat straw, 7.39 L for 40 g/L and 8.22 L for 45 g/L. The degree of biodegradation was calculated to be 68.9%, 74% and 72%, respectively. A fast, effective process for biogas production was developed from native wheat straw, with the highest quantity of daily biogas production occurring between day 2 and day 5. Biomethane concentration in the biogas was 60%. An analysis of bacterial diversity by metagenomics revealed that more than one third of bacteria belonged to class Clostridia (32.9%), followed by Bacteroidia (21.5%), Betaproteobacteria (11.2%), Gammaproteobacteria (6.1%), and Alphaproteobacteria (5%). The most prominent genera among them were Proteiniphilum , Proteiniborus , and Pseudomonas . Archaeal share was 1.37% of the microflora in the thermophilic bioreactor, as the genera Methanocorpusculum , Methanobacterium , Methanomassiliicoccus , Methanoculleus , and Methanosarcina were the most abundant. A knowledge of the microbiome residing in the anaerobic digester can be further used for the development of more effective processes in conjunction with theidentified consortium.

Anaerobic digestion (AD) is a microbially-driven process enabling energy production. Microorganisms are the core of anaerobic digesters and play an important role in the succession of hydrolysis, acidogenesis, acetogenesis, and methanogenesis processes. The diversity of participating microbial communities can provide new information on digester performance for biomass valorization and biofuel production. In this study anaerobic systems were used, operating under mesophilic conditions that realized biodegradation processes of waste wheat straw pretreated with NaOH-a renewable source for hydrogen and methane production. These processes could be managed and optimized for hydrogen and methane separately but combining them in a two-stage system can lead to higher yields and a positive energy balance. The aim of the study was to depict a process of biohydrogen production from lignocellulosic waste followed by a second one leading to the production of biomethane. Archaeal and bacterial consortia in a two-stage system operating with wheat straw were identified for the first time and the role of the most important representatives was elucidated. The mixed cultures were identified by the molecular-biological methods of metagenomics. The results showed that biohydrogen generation is most probably due to the presence of Proteiniphilum saccharofermentans , which was 28.2% to 45.4% of the microbial community in the first and the second bioreactor, respectively. Archaeal representatives belonging to Methanobacterium formicicum (0.71% of the community), Methanosarcina spelaei (0.03%), Methanothrix soehngenii (0.012%), and Methanobacterium beijingense (0.01%) were proven in the methane-generating reactor. The correlation between substrate degradation and biogas accumulation was calculated, together with the profile of fatty acids as intermediates produced during the processes. The hydrogen concentration in the biogas reached 14.43%, and the Methane concentration was 69%. Calculations of the energy yield during the two-stage process showed 1195.89 kWh·t -1 compared to a 361.62 kWh·t -1 cumulative yield of energy carrier for a one-stage process.

Isolation and characterization of new biologically active substances affecting cancer cells is an important issue of fundamental research in biomedicine. Trehalose lipid was isolated from Rhodococcus wratislav i ensis strain and purified by liquid chromatography. The effect of trehalose lipid on cell viability and migration, together with colony forming assays, were performed on two breast cancer (MCF7-low metastatic; MDA-MB231-high metastatic) and one "normal" (MCF10A) cell lines. Molecular modeling that details the structure of the neutral and anionic form (more stable at physiological pH) of the tetraester was carried out. The tentative sizes of the hydrophilic (7.5 Å) and hydrophobic (12.5 Å) portions of the molecule were also determined. Thus, the used trehalose lipid is supposed to interact as a single molecule. The changes in morphology, adhesion, viability, migration, and the possibility of forming colonies in cancer cell lines induced after treatment with trehalose lipid were found to be dose and time dependent. Based on the theoretical calculations, a possible mechanism of action and membrane asymmetry between outer and inner monolayers of the bilayer resulting in endosome formation were suggested. Initial data suggest a mechanism of antitumor activity of the purified trehalose lipid and its potential for biomedical application., Competing Interests: The authors declare no conflict of interest.

Taking into account the rising trend of the incidence of cancers of various organs, effective therapies are urgently needed to control human malignancies. However, almost all chemotherapy drugs currently on the market cause serious side effects. Fortunately, several studies have shown that some non-toxic biological macromolecules, including algal polysaccharides, possess anti-cancer activities or can increase the efficacy of conventional chemotherapy drugs. Polysaccharides are characteristic secondary metabolites of many algae. The efficacy of polysaccharides on the normal and cancer cells is not well investigated, but our investigations proved a cell specific effect of a newly isolated extracellular polysaccharide from the red microalga Porphyridium sordidum . The investigated substance was composed of xylose:glucose and galactose:manose:rhamnose in a molar ratio of 1:0.52:0.44:0.31. Reversible electroporation has been exploited to increase the transport through the plasma membrane into the tested breast cancer tumor cells MCF-7 and MDA-MB231. Application of 75 µg/mL polysaccharide in combination with 200 V/cm electroporation induced 40% decrease in viability of MDA-MB231 cells and changes in cell morphology while control cells (MCF10A) remained with normal morphology and kept vitality., Competing Interests: The authors have declared no conflict of interest., (© 2019 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)

Production of a rhamnolipid biosurfactant by cells of Pseudomonas aeruginosa strain BN10 immobilized into poly(ethylene oxide) (PEO) and polyacrylamide (PAAm) cryogels was investigated under semicontinuous shake flask conditions and compared to biosurfactant secretion by free cells. The biosurfactant synthesis was followed over 9 cycles of operation of the immobilized system, each cycle comprising 7 days at ambient temperature and neutral pH. Type and quantity of the carrier were optimized for the rhamnolipid production. The highest rhamnolipid yield of 4.6 g l(-1) was obtained in the 6th cycle for the immobilized system with 3 g PEO compared to 4.2 g l(-1) obtained for the free cells, thus immobilization provided physiological stability of the cells. Scanning electron microscopy revealed preservation of the cell shape and regular distribution of the cells under the matrix surface. The polymer matrices possessed chemical and biological stability and very good physico-mechanical characteristics which are a prerequisite for a high life span of these materials for the production of rhamnolipids.

Alpha-Galactosidase production by the fungus Humicola lutea 120-5 immobilized in a hybrid sol-gel matrix, consisting of tetraethylorthosilicate (TEOS) as a precursor and a mixture of polyethyleneglycol (PEG) and polyvinylalcohol (PVA), was investigated under semicontinuous shake flask cultivation and compared to the enzyme secretion by free cells. The influence of the carrier weight on the alpha-galactosidase biosynthesis in repeated batch experiments was followed. Best results were obtained with 2 g of the sol-gel particles per culture flask using 144-h runs. The growth behaviour of the immobilized mycelium during both the growth and productive phases was observed by scanning electron microscopy. The presence of abundant mycelial growth of intact hyphae correlated with a 2-fold higher enzyme activity compared to free cells. The obtained biocatalyst retained a high level of enzyme titer exceeding the activity of free cells during four cycles of operation (24 days). This result is confirmed by the micrographs showing the retained viability of the growing vegetative cells due to the protective role of the carrier.

Thermostable alpha-amylase with temperature optimum at 80 degrees C, molecular mass 58 kDa and pI point 6.9 was purified from a catabolite resistant Bacillus licheniformis strain. The enzyme was sensitive to inhibition by metal ions and N-bromosuccinimide. The partition behaviour of this enzyme in aqueous two-phase systems (ATPS) of the polymer-polymer-water type was investigated and some effects of type, molecular weight and concentration of phase components were studied. Up to 100% retention in the bottom phase of polyethylene glycol 10,000-20,000/dextran 200 system was reached. Best partition conditions were obtained in PEG 10,000-20,000/polyvinyl alcohol 200 systems, where the partition coefficient K increased 750 times to 7.5. Simultaneous production and purification of alpha-amylase and serine proteinase in PEG-polymer-water ATPS were examined. In the system PEG 6,000/ficoll, up to 90% of the amylase was retained in the bottom phase, whereas about 95% of the total protein (K = 22.8) and 60-75% of the proteinase were in the top phase. Similar separation of the enzymes from laboratory supernatant was obtained in system PEG/Na2SO4.