Enhanced phenanthrene biodegradation in river sediments by harnessing calcium peroxide nanoparticles and minerals in Sphingomonas sp. DSM 7526 cultivation.

Coupling chemical oxidation and biodegradation to remediate polycyclic aromatic hydrocarbon (PAH)-contaminated sediment has recently gained significant attention. In this study, calcium peroxide nanoparticles (nCaO2) were utilized as an innovative oxygen-releasing compound for in-situ chemical oxidation. The study investigates the bioremediation of phenanthrene (PHE)-contaminated sediment inoculated with Sphingomonas sp. DSM 7526 bacteria and treated with either aeration or nCaO2. Using three different culture media, the biodegradation efficiencies of PHE-contaminated anoxic sediment, aerobic sediment, and sediment treated with 0.2% w/w nCaO2 ranged from 57.45% to 63.52%, 69.87% to 71.00%, and 92.80% to 94.67%, respectively. These values were significantly higher compared to those observed in non-inoculated sediments. Additionally, the type of culture medium had a prominent effect on the amount of PHE removal. The presence of minerals in the culture medium increased the percentage of PHE removal compared to distilled water by about 2-10%. On the other hand, although the application of CaO2 nanoparticles negatively impacted the abundance of sediment bacteria, resulting in a 30-42% decrease in colony-forming units after 30 days of treatment, the highest PHE removal was obtained when coupling biodegradation and chemical oxidation. These findings demonstrate the successful application of bioaugmentation and chemical oxidation processes for treating PAH-contaminated sediment.

Identification of phytochemical, antioxidant, anticancer and antimicrobial potential of Calotropis procera leaf aqueous extract.

Since the dawn of civilization, people have turned to plants as a safe and efficient form of treatment for a variety of diseases. It has long been known that Calotropis procera has the potential to treat a number of diseases. In this study, the C. procera leaf aqueous extract was obtained using the maceration method, and p-coumaric was found to be the main compound. The extract was rich in phenols (174.82 mg gallic acid equivalent/g) and flavonoids (1781.7 µg quercetin equivalent/g). The extract had high antioxidant properties, as indicated by the IC50 values obtained for 2,2-diphenyl-1-picrylhydrazyl (DPPH) (366.33 µg/mL) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) (169.04 µg/mL), as well as the ferric ions reducing antioxidant power (FRAP) (1.67 µg ascorbic acid equivalent/g of the extract). The cytotoxicity of the extract was evaluated against the survival of HT 29 cells, and the IC50 was found to be 236.87 µg/mL. The most resistant and sensitive strains to the extract were Escherichia coli and Staphylococcus aureus, respectively. The morphological changes of these strains were demonstrated through scanning electron microscopy and confocal laser scanning microscopy. The C. procera extract could be therefore used as an antioxidant, antimicrobial, and anticancer agent.

Facile Capture of Recombinant Human Erythropoietin on Mesoporous Affinity Hydrogel Matrix Functionalized with Azoboronate.

Boronate affinity ligands (BALs) have gained attention for glycoproteins capture and recognition due to their unique affinity interaction with glycans. In this paper, the effect of azo immobilization of phenylboronic acid on the reduction of adsorption pH of a recombinant glycoprotein (i.e., rhEPO) on hydrogel microparticles was investigated. To evaluate the influence of intraparticle porosity on protein adsorption, microporous (MicroBead) and mesoporous (MesoBead) agarose beads carrying two levels of amine densities were functionalized with azoboronate ligand. Affinity adsorption of the glycoprotein during static and dynamic adsorptions at relatively low pHs of 8 and 7 was studied. Results revealed successful adsorption of rhEPO at pH = 8 through affinity capture of glycans by azoboronate ligands. Increased amine density provided 1.1 and 1.5 times higher static adsorption capacities and dynamic performance efficiencies, respectively. In addition, adsorption capacities and initial adsorption rates of rhEPO on MesoBeads were respectively 1.4 and 2.5-2.8 times of MicroBeads. Also, at pH = 8, MesoBeads recorded higher dynamic recoveries (59 and 91%) compared with microporous ones (46 and 69%) since mesoporosity facilitates intraparticle mass transfer. Reduction of binding pH from 8 to 7 resulted in a sharp decrease in dynamic recovery (14%), indicating the appropriate binding pH of azoPBA to be above 7. The azoboronate affinity ligand is a leading candidate for capturing glycoproteins at relatively low pH. Also, mesoporous microparticles are appropriate tools in more efficient medium-sized protein binding applications.

Hybrid powdered activated carbon-activated sludge biofilm formation to mitigate biofouling in dynamic membrane bioreactor for wastewater treatment.

Membrane costs and biofouling limit applications of membrane bioreactors (MBRs) for wastewater treatment. Here, powdered activated carbon (PAC) utilization in the formation and performance of a self-forming dynamic membrane consisting of activated sludge and PAC during hybrid wastewater treatment process was studied. Short-term agitation helped (non)biological particles to quickly uniformly settle on mesh filter, forming more uniform PAC-containing dynamic membranes (PAC-DMs). PAC adsorbed adhesive materials, resulting in an increase in average floc size and DM permeability while decreasing biofouling. The most efficient PAC concentration was 4 g L-1 considering techno-economics, i.e. the highest effluent quality (turbidity of 19.89 NTU) and the lowest biofouling (transmembrane pressure rise of 2.89 mbar). Short-term performance of hybrid PAC-DM bioreactor (PAC-DMBR) showed stability in effluent quality improvement including 92%, 95%, 83%, 84% and 98% reductions in turbidity, chemical oxygen demand, total dissolved solids, total nitrogen, and total phosphorous, respectively. Accordingly, adopting hybrid PAC-DMBR has potential to alleviate biofouling and capital cost.

Influence of alumina nanoparticles on the performance of polyacrylonitrile membranes in MBR.

This study aims to investigate the effect of using Al2O3 nanoparticles (NPs) in membrane structure on the operation condition of the membrane bioreactor. To this end, alumina NPs as the high hydrophilic agents with an approximate size of 40 nm and a concentration of 0-3 wt.% were placed within the PAN polymeric membrane matrix structure with high hydrophilicity and high mechanical resistance over the others via the phase inversion method. Characterization of synthesized nanocomposite membranes was carried out by SEM analysis. In the presence of the alumina NPs, the porosity of the membranes improved. The water contact angle measurement confirmed the superior hydrophilicity of mixed PAN membranes compared to the pure polymeric membranes. The best nanocomposite membrane with better antifouling properties was selected to evaluate the MBR's performance in wastewater treatment and assessed in terms of the resistance, flux recovery, and COD removal rates. The result of a comparison with pure membrane showed that by increasing the Al2O3 amount up to 2wt.%, irreversible fouling resistance mitigated as much as 50%. Moreover, the flux recovery ratio was increased by 15%, and the COD removal rate was also raised as large as 16%. Our investigation illustrated that the presence of alumina NPs has improved the MBR performance and decreased the irreversible fouling resistance of the membrane.

Investigation of the chemical properties of Mentha pulegium essential oil and its application in Ocimum basilicum seed mucilage edible coating for extending the quality and shelf life of veal stored in refrigerator (4°C).

Nowadays, the tendency toward the application of natural preservatives to extent the shelf life of food products has grown. The purpose of the present research was to evaluate the effect of the basil seed mucilage (BSM)-based edible coating containing different concentrations of Mentha pulegium essential oil (MPEO) on the shelf life of the veal stored at refrigerator temperature. Firstly, the chemical composition and functional groups of MPEO were detected through gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FTIR). Then, the BSM-based edible coatings containing 0%, 0.5%, 1%, 1.5%, and 2% MPEO were prepared, and the veal samples were coated with them. The physicochemical, microbial, and sensory properties of the samples were investigated during the 9-day storage period at 4°C. Twenty-five compounds were detected in MPEO with limonene being the major one (28.44%). The results revealed that the lightness, hardness, and moisture content of the samples decreased during storage. The coating containing the essential oil could properly restrain the rise in pH, peroxide value (PV), and thiobarbituric acid value (TBA). Based on microbial analyses, the shelf life of the coated sample without the essential oil and those containing 0.5%, 1%, 1.5%, and 2% of the essential oil were, respectively, extended up to 3, 6, 9, 9, and 9 days relative to the control. Moreover, the coating containing the essential oil produced no unfavorable effect on the sensory properties of the meat samples. In conclusion, the BSM-based edible coating containing different concentrations of MPEO can be applied as a natural preservative to enhance the resistance of meat products against microbial spoilage and fat oxidation.

Magnetic MBR technology: from the fabrication of membrane to application in wastewater treatment.

The aim of this study is to synthesize a magnetic nanocomposite membrane using iron oxide and alumina nanoparticles and employing it in magnetic membrane bioreactors (MBRs) for oily wastewater treatment. Al2O3 and Fe3O4 nanoparticles with approximate sizes of 20 and 30 nm respectively, were settled into a polysulfone (PSf) membrane matrix via magnetic casting method. The concentration of alumina and iron oxide nanoparticles were 0-0.25 wt% and 0.03 wt%, respectively. Compared with the blank membrane, an increase in the concentration of Fe3O4 up to 0.2 wt%, led to the flux as much as 70% and mitigated total resistance by 70%. The presence of the magnetic field around the bioreactor increased the flux significantly and reduced the cake resistance by 93%. Moreover, by applying the static magnetic field to MBR, the Chemical Oxygen Demand (COD) removal rate was increased to 93%, while in the MBR without the magnetic field the COD removal rate was 80%. Our investigation illustrated that the magnetic casting is an effective method to improve the flux and mitigate the fouling of the magnetic nanocomposite membrane. The output of this research indicates that the magnetic casting method enhance the magnetic MBRs performance for wastewater treatment.

Quality retention and shelf life extension of fresh beef using Lepidium sativum seed mucilage-based edible coating containing Heracleum lasiopetalum essential oil: an experimental and modeling study.

The instability and strong flavor or odor of essential oils (EO) limit their direct incorporation into food products. In this study, the antioxidant and antimicrobial Heracleum lasiopetalum essential oil (HLEO) was added to Lepidium sativum seed mucilage (LSSM) solution at four concentrations (0, 0.5, 1, and 1.5%) to develop a novel edible coating and expand its food application. HLEO-loaded LSSM coating was then used to improve the shelf life and quality of beef as a model food system. The coated and control beef samples were periodically analyzed for physicochemical analysis, microbiological, and sensory characteristics over a period of 9 days at 4 °C. The HLEO-enriched LSSM coating, particularly 1.5% loaded one resulted in a significant (p < 0.05) increase in oxidative and microbiological stability and overall acceptance of the beef samples, compared to the control counterpart. HLEO-loaded LSSM coating, therefore, provides a promising alternative to preserve the meat products under cold storage.

Efficacies of Two Nano-Formulations of Tasmanian Blue Gum Essential Oil to Control Callosobruchus maculatus.

Botanical insecticides, including essential oils (EOs), can be considered as appropriate alternatives to synthetic insecticides for controlling stored product pests. In this study, potential of nano-formulations of the Tasmanian blue gum (TBG) EO to control Callosobruchus maculatus Fabricius (Coleoptera, Bruchidae) were evaluated under laboratory condition. Two nano-emulsion formulations of the EO were provided using gum Arabic and Span 80 as surfactants. Contact as well as fumigant toxicities of the formulations to the beetle adults were compared with the bulk EO in 1, 2, and 3 d after treatment. Results showed that all formulations were toxic to the adults. After 1, 2, and 3 d of treatment, the estimated LC50 values in contact and fumigant applications varied from 1.37 to 8.53 ppm and 0.05 to 0.44 ppm for various formulations. Both nano-formulations cause significant stability enhancement of the EO. Moreover, the EO had significant repellent and ovicidal effects on the insect. The insecticidal effects of the EO in nano-formulations were significantly greater than in the bulk form. The EO constituted 22 compounds, from 5 classes. Eucalyptol (43.79%) is the main constituent of the TBG EO.

Heterologous production of porcine derived antimicrobial peptide PR-39 in Escherichia coli using SUMO and intein fusion systems.

About half a century after antibiotics discovery, multi-antibiotic-resistant bacteria posed a new challenge to medicine. Attempts to discover new antibiotics have drawn the attention to Antimicrobial Peptides (AMPs). The rapid growth, besides its known genetic and manipulation systems, makes E. coli the preferred host system for production of recombinant proteins on an industrial scale. To produce AMPs in E. coli, the application of fusion-tags with the aim of stability, solubility, and prevention of antimicrobial activity is one of the best practices in this regard. In this study, we presented two different expression systems for the production of PR-39 in E. coli; one in fusion with intein-Chitin binding domain (CBD) and another in fusion with SUMO accompanied by polyhistidine affinity tag. Both were cloned in the NdeI-XhoI sites of pET-17b and transformed to E. coli BL21 (DE3) pLysS. Recombinant bacteria were cultured and induced with 0.4 mM IPTG at 30 °C. Expression and purification of target proteins were confirmed by Tricine- SDS-PAGE and dot blot analysis. Recovery of 250 µg PR-39/L from SUMO fusion system and 280 µg PR-39/L from the intein fusion system was achieved. Both purified peptides showed antibacterial activity using MIC/MBC demonstrating their functionality after SUMO and intein mediated purification.

Employing magnetism of Fe3O4 and hydrophilicity of ZrO2 to mitigate biofouling in magnetic MBR by Fe3O4-coated ZrO2/PAN nanocomposite membrane.

The aim of this research is benefiting from the synergistic effect of the simultaneous presence of Fe3O4 and ZrO2 in the form of Fe3O4-coated ZrO2 (Fe3O4@ZrO2) nanoparticles within the structure of PAN membrane to reduce membrane fouling. The role of Fe3O4 nanoparticles in increasing the pore size and magnetic saturation as well as the role of ZrO2 in decreasing surface roughness and hydrophobicity can mitigate membrane fouling in magnetic-assisted membrane bioreactors. For this purpose, Fe3O4, ZrO2, and Fe3O4@ZrO2 nanoparticles were embedded into PAN membrane structure and magnetic (M nM), hydrophilic (H nM), and magnetic-hydrophilic (HM nM) membranes were synthesized. H 1M (1ZrO2/PAN) membrane with a contact angle of 31 degrees, M 1N (1Fe3O4/PAN) with a pore size of 90 nm, and H 3M (3ZrO2/PAN) membrane with an RMS roughness of 13.5 nm were the most hydrophilic, porous, and smoothest membranes, respectively. High sensitivity to magnetic field along with high porosity, high hydrophilicity and low surface roughness simultaneously exist within the structure of MHMs membranes, such that MH 1M (1Fe3O4@ZrO2/PAN) indicated 116% greater flux, 121% greater flux recovery, and 85% less total filtration resistance in comparison with the blank membrane in magnetic membrane bioreactor, at a magnetic field intensity of 120 mT and MLSS = 10,000 mg/l. As an overall conclusion, the output of this research was compared with other research in term of normalized flux. Results reveal that at MLSS = 10,000 mg/l, HRT = 8 h and TMP = 0.3 bar, MH 1M membrane has normalized flux equal to 1.56 g/m2 h bar which is an acceptable value compared to normalized flux reported by other researchers.

Biodegradation of long chain alkanes in halophilic conditions by Alcanivorax sp. strain Est-02 isolated from saline soil.

In this study, through a multistep enrichment and isolation procedure, a halophilic bacterial strain was isolated from unpolluted saline soil, which was able to effectively and preferentially degrade long chain alkanes (especially tetracosane and octacosane). The strain was identified by 16S rRNA gene sequence as an Alcanivorax sp. The growth of strain Est-02 was optimized at the presence of tetracosane in different NaCl concentrations, temperatures, and pH. The consumption of different heavy alkanes was also investigated. Optimal culture conditions of the strain were determined to be as follows: 10% NaCl, temperature 25-35 °C and pH 7. Alcanivorax sp. strain Est-02 was able to use a wide range of aliphatic substrates ranging from C14 to C28 with clear tendency to utilize heavy chain hydrocarbons of C24 and C28. During growth on a mixture of alkanes (C14-C28), the strain consumed 60% and 65% of tetracosane and octacosane, respectively, while only about 40% of the lower chain alkanes were degraded. This unique ability of the strain Est-02 in efficient and selective biodegradation of long chain hydrocarbons could be further exploited for remediation of wax and heavy oil contaminated soils or upgrading of heavy crude oils. Comparison of the sequence of alkane hydroxylase gene (alkB) of strain Est-02 with previously reported sequences for Alcanivorax spp. and other hydrocarbon degraders, showed a remarkable phylogenetic distance between the sequence alkB of Est-02 and other alkane-degrading bacteria.

Antioxidant activities and bioactive compounds of five Jalopeno peppers (Capsicum annuum) cultivars.

The present study was designed to evaluate the contents of different antioxidants compounds and their antioxidant activities in Jalopeno peppers (Capsicum annuum) cultivars (El Dorido, Grande, Tula, Sayula and El Rey) extracts. Free radical scavenging activity of Grande was recorded as high as 87% followed by El Dorido (83%). Results of reducing power (Fe3+ to Fe2+) showed that Grande (0.85%) and El Dorido (0.81%) fruit extract absorbance value were close to synthetic antioxidant BHT (0. 97%) obtained at100 µg/mL. The results showed that total phenolic content of El Dorido and Grande were significantly higher compared to other Jalapeno pepper. Results indicated strong and positive correlation between antioxidant activity and carotenoids content (r = 0.75), vitamin C (r = 0.78) and total capsaicinoids (r = 0.84), respectively. The results of the antioxidant activity assays showed that the El Dorido and Grande had strongest antioxidant activity compared to other peppers cultivars in this study.

Towards rational design of porous nanostructured biopolymeric microparticles for biomacromolecules separation: A case study of intraparticle diffusion facilitation and BSA adsorption on agarose microspheres.

Synthesis and employing advanced materials for emerging applications is of great challenge for the scientific community. Recombinant proteins production and purification is one of the fastest growing fields in the global economy. In this regard, it is essential to fabricate biocompatible low-cost materials with high specificity to enhance purification efficiency. This requires the regulation of mass transfer based on the protein molecular size and interactions with the matrix interface; thus, needs synthesizing novel materials with tuned porosity. In this study, we proposed rational alteration in porous structure of biopolymeric microspheres using appropriate-sized porogen to facilitate intraparticle molecular diffusion. The tailored porous nanostructures, which were generated by phase separation in the polymer blend of agarose and polyethylene glycol, were analyzed with optical and scanning electron microscopy, Fourier transform infrared spectroscopy, water diffusion, and albumin adsorption. The well-tuned beads possessed highly porous structures with dominant mesopores owing to PEG phase migration out of the network. The high speed homogenizer caused an uncommon dense morphology with interwoven two-type porosity. Optimally tuned mesoporous beads with considerably high specific surface area exhibited dramatically fast and enhanced intraparticle diffusion of both water and protein molecules. Thus, the introduced porosity modification is a promising design for enhancing mass transfer in the bio-separation process. Finally, useful insights for developing future smart hydrogel microparticles with tuned porous network for biomolecules purification are provided by the conducted experiments.

Functional synergy of anti-mir221 and nanohydroxyapatite scaffold in bone tissue engineering of rat skull.

An appropriate cell source, effective cell modification, and proper supportive matrices are the main bases of tissue engineering. The effectiveness of anti-mir221 or hydroxyapatite (HA) in improving the osteogenic differentiation of mesenchymal stem cells (MSCs) has been reported previously. Herein, simultaneous application of these osteogenic inducers was investigated in vivo. The Poly-caprolactone (PCL)/HA nanofibers were characterized using contact angle measurement, tensile test, Fourier transform infrared spectroscopy, and electron microscopy. Rat MSCs were isolated, characterized and transfected with anti-mir221. The rats were divided into 4 groups and an 8 mm defect were created in the mid-calvaria of each rat by trephine bur. Group 1 received (PCL)/HA nanofibers, group 2 received (PCL)/HA nanofibers plus autologous MSCs, group 3 received (PCL)/HA nanofibers plus MSCs transfected with anti-mir221, and group 4 rats were left empty as an additional control group. Histomorphometric and radiomorphometric evaluation after 4 and 8 weeks revealed more new bone formation in the cell-treated groups compared to the scaffold alone group. There was evidence for a combination of increased osteoclasts and osteoblast vascular lake containing red blood cells in the anti-mir221 transfected group. New bone penetration into the scaffolds empirically demonstrated the capability of this combination for efficient osteointegration. Altogether, the co-application of HA and anti-mir221 transfected cells can enhance bone healing of the rat skull.

Crocin loaded nano-emulsions: Factors affecting emulsion properties in spontaneous emulsification.

Spontaneous emulsification may be used for encapsulating bioactive compounds in food and pharmaceutical industry. It has several advantages over high energy and other low energy methods including, protecting sensitive compounds against severe conditions of high energy method and its ability to minimize surfactant, removal of cosurfactant and thermal stability compared with other low energy methods. In this study, we examined possibility of encapsulating highly soluble crocin in W/O micro-emulsions using spontaneous method which further could be used for making double emulsions. Nonionic surfactants of Span 80 and polyglycerol polyricinoleate (PGPR) were used for making micro-emulsions that showed the high potential of PGPR for spontaneous method. Surfactant to water ratio (SWR%) was evaluated to find the highest amount of aqueous phase which can be dispersed in organic phase. Droplet size decreased by increasing SWR toward the SWR=100% which had the smallest droplet size and then increased at higher levels of surfactant. By increasing SWR, shear viscosity increased which showed the high effect of PGPR on rheological properties. This study shows in addition to W/O micro-emulsions, spontaneous method could be used for preparing stable O/W micro-emulsions.

Dynamic membrane behaviours during constant flux filtration in membrane bioreactor coupled with mesh filter.

This study investigated the long-term filtration of mesh filter with the formed dynamic membrane in bioreactor. The trend of transmembrane pressure (TMP) variations highly corresponded to the thickness and compactness index of dynamic membrane. The dynamic membrane was fractionated by applying two cleaning protocols, that is, rinsing and chemical cleaning. The desorbed fraction, consisting of soluble microbial products (>70%), provided a stickiness surface for formation of consecutive biomass layer which featured a high concentration of extracellular polymeric substances (>75%). The chemical oxygen demand (COD) removal was 70%, 89%, and 92% for period of 0-26, 26-49, and 49-67 day, respectively, which indicated that further development of dynamic membrane increased the TMP without improvement in the effluent quality (TMP: 50-200 mbar, COD removal: 89%; TMP: 200-600 mbar, COD removal: 92%). The average NH4+-N and TN removal was about 76% and 21%, respectively. The effluent turbidity fell less than 2 NTU after 26 days of filtration.

Reduction of membrane fouling by innovative method (injection of air jet).

BACKGROUND: One of the most important challenges about the Membrane Bio Reactors is membrane fouling. Fouling has been at the centre of a globe debate for more recent years. It leads to high operational and maintenance costs such as membrane damage and replacement of membrane. Membrane fouling is attributed to the physicochemical interactions between the bio fluid and membrane. In order to decrease the fouling in bioreactors there are common anti fouling strategies such as operation at low flux, Optimization of aeration flow-rate and Physical and chemical cleanings. However, often they are not effective. METHODOLOGY: This work deal with fouling crisis by a new and innovative method in order to reduce of fouling on membrane surface by injection of parallel air jet on membrane bio reactor. This is a new idea and fundamental study about the influence of wall jet on fouling of membrane surface. This study is included both experimental and numerical investigations. In order to polarize the stream path on the surface of the membrane, four symmetric nozzles were implemented at the bottom of the membrane surface upon the sparger. The changes in the fouling resistance were experimentally measured at five various jet velocities and all of them recorded by a computer system. In addition the effect of air jet velocity and shear stress on fouling resistances was also investigated by computational fluid dynamics at the similar conditions. RESULTS: It was revealed that the permeate flux and resistance of fouling can be related to shear stress of air flow at the membrane surface. When the velocity of air jets increase, the permeate flux increase too. Also, results illustrate that jet injection can partially remove the cake which was formed on the surface of the membrane. CONCLUSIONS: Correlations were developed for estimating each resistance of the membrane surface via the shear stress. The resistances of the cake are removed by the jet velocity changes, from 20% in lower jet velocity up to 40% in higher jet velocity.

Dielectric monitoring and respirometric activity of a high cell density activated sludge.

A novel method was developed to assess the viability of activated sludge present in a biological wastewater treatment process and signify its distinction from respirometric activity. The respirometric activity and viability of activated sludge at high cell density, such as typically encountered in membrane bioreactors, were investigated in batch and fed-batch systems. The method for measuring the viability of activated sludge was based on the sludge permittivity monitored online by a capacitive sensor. Results from permittivity measurement were compared with usual biological activity measurement through oxygen uptake rate determination. The similar downward trend was observed for both measurements. The respirometric activity and permittivity, respectively, reduced to 50% and 68% of initial value in the fed-batch system and 18% and 27% of initial value for the batch system which was due to quantitative and qualitative changes in the microbial culture in the activated sludge. The novel method allows to made distinction between viable versus dead and inactive versus active microbial cells in the activated sludge system and can be used for better and more efficient control of the biological processes.

Effect of microalgae/activated sludge ratio on cooperative treatment of anaerobic effluent of municipal wastewater.

In this work, capability of the green microalga (MA), Chlorella vulgaris, in treating synthetic anaerobic effluent of municipal wastewater was investigated. While pure C. vulgaris (100 % MA) provided maximum soluble chemical oxygen demand (sCOD) and N-NH4(+) removal efficiencies of 27 and 72 % respectively, addition of activated sludge (AS) to MA in different mass ratios (91, 80, 66.7, 9 % MA) improved wastewater treatment efficiency. Thus giving maximum sCOD and N-NH4(+) removal efficiencies 85 and 86.3 % (for MA/AS = 10/1), respectively. Utilizing AS without C. vulgaris, for treating the synthetic wastewater resulted in 87 % maximum sCOD and 42 % maximum N-NH4(+) removal efficiencies. Furthermore, algal growth and specific growth rates were measured in the systems with microalga as the dominant cellular population. As a result, faster algal growth was observed in mixed systems. Specific growth rate of C. vulgaris was 0.14 (day(-1)) in 100 % MA and 0.39 (day(-1)) in 80 % MA. Finally, data gathered by online measurement of dissolved oxygen indicate that algae-activated sludge mixture improves photosynthetic activity of examined microalga strain during anaerobic effluent treatment.