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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. [ABSTRACT FROM AUTHOR]

The combination of chemical and biological treatments is an efficient approach for a complete removal of emerging contaminants such as pharmaceuticals. In this study, the removal of a mixture of anti-inflammatories (naproxen and diclofenac), antibiotics (azithromycin and trimethoprim), and hormones (levonorgestrel and medroxyprogesterone) was investigated using a membrane bioreactor (MBR) coupled with an ozonation system. The results showed complete removal of selected pharmaceuticals only after 50 days of the experiment in the MBR+O3 system, while in the MBR system the average removal rate was 35%. Response surface methodology (RSM) was also utilized to statistically analyze the effects of process parameters and optimize the experimental conditions. Based on the RSM results, experiment time significantly impacted COD, BOD, and TDS removal. Also, the optimal conditions for ozonation time and ozone dose were determined to be 4 min and 5 mg/l, respectively. Based on the optimization approach achieved by RSM, the final concentrations of 44.3, 12.3, and 51.6 mg/l were obtained for COD, BOD, and TDS, respectively. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The main purpose of this research is to use aluminum oxide nanoparticles in order to manipulate the formation mechanism of poly acrylonitrile (PAN) UF membranes with the aim of improving their performance in separating biological macromolecules including sodium alginate, humic acid, bovine serum albumin (BSA). For this purpose, alumina nanoparticles with the approximate size of 40 nm and high hydrophilicity properties were placed within the structure of the PAN membrane to engineering design of pores. Viscometry analysis and determination of cloud point were performed in order to investigate the formation mechanism of the nanocomposite membrane. Chemical, surface, and morphological variations of the nanocomposite membrane were evaluated using FTIR, zeta potential, contact angle, DLS, porosity metering, SEM, and AFM analyses. Eventually, investigation of the filtration performance of the nanocomposite membranes showed that the membranes containing 1 wt% of alumina nanoparticles have a water flux 57% more than that of raw membrane. Further, in terms of flux recovery parameter, this membrane indicated 22, 9, and 14% increase for sodium alginate, humic acid, and BSA, respectively. Regarding extent of dye separation, sodium alginate separation, humic acid separation, and BSA separation, 12, 7, 9, and 7% increase was observed for the nanocomposite membrane containing 3 wt% of alumina nanoparticles. [ABSTRACT FROM AUTHOR]

In this study, the effect of mixotrophic, heterotrophic, photoautotrophic (CO2 of air source), and photoautotrophic (bicarbonate source) cultivation of Chlorella vulgaris was investigated on microalgae growth rate and nutrient removal under different kinds of nitrogen sources. The highest N-NH3+, N-NO3−, P-PO43− (in ammonium source), and P-PO43− (in nitrate source) removal efficiency (87.28 ± 0.89, 70.00 ± 1.20, 87.00 ± 3.10, and 78.10 ± 1.95%, respectively) was reached in the mixotrophic culture. In all cultivations, when nitrate was used as the nitrogen source, specific growth rate, biomass productivity, and specific oxygen production rate (SOPR) were higher than the one with ammonium source due to decreased pH. However, in all cultures except for photoautotrophic cultivation (in the CO2 of the air), nitrogen removal rates improved in the ammonium source. In addition, in both ammonium and nitrate source, the respiration activity of mixotrophic microalgae was higher than the photosynthetic activity of the cells. When CO2 was used as inorganic carbon, the specific growth rate of microalgae was lower than with the bicarbonate source. Based on the obtained results, mixotrophic conditions would be the most useful cultivation for application in N-rich wastewater treatment systems. [ABSTRACT FROM AUTHOR]

There is a lack of fundamental knowledge about the scale up of biosurfactant production. In order to develop suitable technology of commercialization, carrying out tests in shake flasks and bioreactors was essential. A reactor with integrated foam collector was designed for biosurfactant production using Bacillus subtilis isolated from agricultural soil. The yield of biosurfactant on biomass ( Yp/x), biosurfactant on sucrose ( Yp/s), and the volumetric production rate ( Y) for shake flask were obtained about 0.45 g g−1, 0.18 g g−1, and 0.03 g l−1 h−1, respectively. The best condition for bioreactor was 300 rpm and 1.5 vvm, giving Yx/s, Yp/x, Yp/s, and Y of 0.42 g g−1, 0.595 g g−1, 0.25 g g−1, and 0.057 g l−1 h−1, respectively. The biosurfactant maximum production, 2.5 g l−1, was reached in 44 h of growth, which was 28% better than the shake flask. The obtained volumetric oxygen transfer coefficient ( KL a) values at optimum conditions in the shake flask and the bioreactor were found to be around 0.01 and 0.0117 s−1, respectively. Comparison of KL a values at optimum conditions shows that biosurfactant production scaling up from shake flask to bioreactor can be done with KL a as scale up criterion very accurately. Nearly 8% of original oil in place was recovered using this biosurfactant after water flooding in the sand pack. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]