Mechanism of heavy metal ion biosorption by microalgal cells: A mathematic approach.

Microalgal biomasses have been established as promising biosorbents for biosorption to remove heavy metal ions (HMIs) from wastewaters and contaminated natural waterbodies. Understanding the mechanism is important for the development of cost-effective processes for large scale applications. In this paper, a simple mathematical model was proposed for the predication of biosorption capacity of HMI by microalgal cells based on single cell mass, cell size, and HMI radius.

Biosorption of heavy metal ions by green alga Neochloris oleoabundans: Effects of metal ion properties and cell wall structure.

Effects of metal ion proprieties and the cell wall structure of green alga Neochloris oleoabundans were investigated on five strategically selected heavy metal ions, Pb(II), Hg(II), Zn(II), Cd(II) and Cu(II). The biosorption of these ions were energy-independent and spontaneous Langmuir adsorption. The adsorption capacities of Pb(II), Hg(II), Zn(II), Cd(II) and Cu(II) were determined to be 1.

Advances in biosynthesis of noble metal nanoparticles mediated by photosynthetic organisms-A review.

The last decade has witnessed significant developments in the biosynthesis of noble metal nanoparticles (NMNPs) due to their distinct advantages in various practical applications. Many photosynthetic organisms, including plants, microalgae, and photosynthetic bacteria, have been explored for NMNP synthesis in an eco-friendly and cost-effective manner. These biomasses were used for NMNP biosynthesis as growing cells, non-growing cells, whole cells extract, disrupted cell extract, residual biomasses, gum solutions, etc.

Micro- and nano-plastics in marine environment: Source, distribution and threats - A review.

Plastic litters have become the predominant components of marine debris due to extensive consumption plastics and mismanagement of plastic wastes. As part of the problem, microplastics (MPs) and nanoplastics (NPs) have generated special concerns due to their unique features that make them easy to transfer among oceans in the marine ecosystem, across different trophic levels inside the food web, and even across different tissues inside contaminated animals. Studies have demonstrated the almost omnipresence of MPs in the marine ecosystem, which present serious threats to the health of marine animals, causing symptoms such as malnutrition, inflammation, chemical poisoning, growth thwarting, decrease of fecundity, and death due to damages at individual, organ, tissue, cell, and molecule levels.

Effects of operating parameters and coexisting ions on the efficiency of heavy metal ions removal by nano-fibrous metal-organic framework membrane filtration process.

The purification process of wastewater containing heavy metal ions (HMIs) using nano-fibrous metal-organic frameworks, MOF-808, embedded polyacrylonitrile membrane has been studied. The process parameters that were evaluated included feed concentration, transmembrane pressure (TMP), and membrane thickness. The effect of coexisting cations in the solution upon the removal efficiencies of Zn, Cd, Pb and Hg ions was also investigated.

Effects of sodium bicarbonate on cell growth, lipid accumulation, and morphology of Chlorella vulgaris.

Background: Low concentration NaHCO (ca. 12 mM) had been demonstrated to be an excellent carbon source for industrially important green alga Chlorella vulgaris and high concentration NaHCO (e.g.

Mechanism of light-dependent biosynthesis of silver nanoparticles mediated by cell extract of Neochloris oleoabundans.

This study investigated the role of chlorophyll and light in the biosynthesis of silver nanoparticles (AgNPs) using disrupted cell aqueous extract of Neochloris oleoabundans. It was found that, while increasing sonication time increased the percentage of disrupted cells and efficiency of aqueous cell extraction, over-sonication reduced AgNPs production. AgNPs biosynthesis required illumination of white, blue, or purple light while AgNPs formation was undetectable under dark condition or illumination of orange or red light, indicating only photons of high energy levels among the photosynthetic active radiations are capable of exciting the electrons of chlorophylls to a state that is sufficient for Ag reduction.

Insight Studies on Metal-Organic Framework Nanofibrous Membrane Adsorption and Activation for Heavy Metal Ions Removal from Aqueous Solution.

Electrospun nanofiber composite membranes containing water-stable metal-organic frameworks (MOFs) particles (Zr-based MOF-808) supported on polyacrylonitrile (PAN) nanofiber synthesized via co-electrospinning have been prepared. MOF particles were dispersed in the organic polymer, and their subsequent presence was inferred by scanning electron microscopy. Membrane performance in heavy metal ion adsorption in batch filtration was evaluated on the basis of Cd and Zn ions sequestration.

Effects of shear stress on microalgae - A review.

Cultivation of microalgae requires consideration of shear stress, which is generated by operations such as mixing, circulation, aeration and pumping that are designed to facilitate mass and heat transfer as well as light distribution in cultures. Excessive shear stress can cause increased cell mortality, decreased growth rate and cell viability, or even cell lysis. This review examines the sources of shear stress in different cultivation systems, shear stress tolerance of different microalgal species and the physiological factors and environmental conditions that may affect shear sensitivity, and potential approaches to mitigate the detrimental effects of shear stress.

Protozoa inhibition by different salts: Osmotic stress or ionic stress?

Cell density and morphology changes were tested to examine the effects of salts including NaHCO , NaCl, KHCO , and KCl at 160 mM on protozoa. It was demonstrated that ionic stress rather than osmotic stress led to protozoa cell death and NaHCO was shown to be the most effective inhibitor. Deformation of cells and cell shrinkage were observed when protozoan cells were exposed to polyethylene glycol (PEG) or any of the salts.

Development of Membrane-Based Desiccant Fiber for Vacuum Desiccant Cooling.

A novel hydrophobic membrane-based desiccant fiber (MDF) was developed by loading lithium chloride into hydrophobic hollow fiber membranes. The MDF thus made was then tested for vapor absorption under controlled conditions. Furthermore, an MDF pad, which was made by weaving MDF into a piece of garment, was built into a laboratory vacuum desiccant cooling (VDC) setup, which included the MDF pad as the desiccant layer and a cooling towel saturated with water as the water reservoir, to test the cooling effects at atmospheric pressure and vacuum of 25 in.

Cultivation of Neochloris oleoabundans in bubble column photobioreactor with or without localized deoxygenation.

This study evaluated long-term non-sterile cultivation of freshwater green alga Neochloris oleoabundans in a 15-liter bubble column photobioreactor (BCPBR) and the effects of a membrane-based localized oxygen remover (LOR) on deoxygenation, cell growth, and lipid production of N. oleoabundans. Batch and continuous cultivations were carried out under non-sterile conditions for 53 days with no detectable protozoa or other biological contaminants, indicating successful long-term contamination-free cultivation.

Enhanced performance of PVDF nanocomposite membrane by nanofiber coating: A membrane for sustainable desalination through MD.

Membrane distillation (MD) is a promising separation technique capable of being used in the desalination of marine and brackish water. Poly(vinylidene fluoride) (PVDF) flat sheet nano-composite membranes were surface modified by coating with electro-spun PVDF nano-fibres to increase the surface hydrophobicity. For this purpose, the nano-composite membrane containing 7 wt.

Control of protozoa contamination and lipid accumulation in Neochloris oleoabundans culture: Effects of pH and dissolved inorganic carbon.

Combined effects of pH (i.e., 7.

Plant essential oils and mastitis disease: their potential inhibitory effects on pro-inflammatory cytokine production in response to bacteria related inflammation.

This paper highlights the role of plant volatile organic compounds, found in essential oils, for the treatment of bacteria related inflammation. This report is focused on tea tree oil, particularly its main compound terpinen-4-ol. Analysis of the published literature shows that many essential oils have significant antibacterial, antifungal and anti-inflammatory effects.

Closed photobioreactors for production of microalgal biomasses.

Microalgal biomasses have been produced industrially for a long history for application in a variety of different fields. Most recently, microalgae are established as the most promising species for biofuel production and CO(2) bio-sequestration owing to their high photosynthesis efficiency. Nevertheless, design of photobioreactors that maximize solar energy capture and conversion has been one of the major challenges in commercial microalga biomass production.

Ice cooling vest on tolerance for exercise under uncompensable heat stress.

This study was conducted to evaluate the effectiveness of a commercial, personal ice cooling vest on tolerance for exercise in hot (35°C), wet (65% relative humidity) conditions with a nuclear biological chemical suit (NBC). On three separate occasions, 10 male volunteers walked on a treadmill at 3 miles per hour and 2% incline while (a) seminude (denoted CON), (b) dressed with a nuclear, biological, chemical (NBC) suit with an ice vest (V) worn under the suit (denoted NBCwV); or (c) dressed with an NBC suit but without an ice vest (V) (denoted NBCwoV). Participants exercised for 120 min or until volitional fatigue, or esophageal temperature reached 39.

Biomass production and nitrogen and phosphorus removal by the green alga Neochloris oleoabundans in simulated wastewater and secondary municipal wastewater effluent.

Biomass productivity of 350 mg DCW L(-1)day(-1) with a final biomass concentration of 3.15 g DCW L(-1) was obtained with Neochloris oleoabundans grown in artificial wastewater at sodium nitrate and phosphate concentrations of 140 and 47 mg L(-1), respectively, with undetectable levels of residual N and P in effluents. In secondary municipal wastewater effluents enriched with 70 mg N L(-1), the alga achieved a final biomass concentration of 2.

Enhancement of lipid production using biochemical, genetic and transcription factor engineering approaches.

This paper compares three possible strategies for enhanced lipid overproduction in microalgae: the biochemical engineering (BE) approaches, the genetic engineering (GE) approaches, and the transcription factor engineering (TFE) approaches. The BE strategy relies on creating a physiological stress such as nutrient-starvation or high salinity to channel metabolic fluxes to lipid accumulation. The GE strategy exploits our understanding to the lipid metabolic pathway, especially the rate-limiting enzymes, to create a channelling of metabolites to lipid biosynthesis by overexpressing one or more key enzymes in recombinant microalgal strains.

Effects of glucose and nitrogen source concentration on batch fermentation kinetics of Lactococcus lactis under hemin-stimulated respirative condition.

Analytical solutions to the ordinary differential equations governing the kinetics of cell growth, substrate utilization, and product formation of batch fermentation processes were derived and used to study the kinetics of the hemin-stimulated respiratory cultivation of Lactococcus lactis at varied initial glucose concentrations and nitrogen source concentrations. Studies revealed that initial glucose concentration varying in the range of 60 to 90 g/L had no significant substrate inhibitive effect. Furthermore, elevating the concentration of complex nitrogen sources while maintaining glucose concentration at 60% led to a high final biomass concentration of 6.

Production and application of bacteriophage and bacteriophage-encoded lysins.

The widespread resistance to antibiotics among pathogenic bacteria has made development of alternatives to antibiotics a pressing public concern. Extensive studies have established bacteriophages (phages) and phage-encoded lytic enzymes (virolysins) as two of the most promising families of alternative antibacterials for the treatment and prophylaxis of bacterial infections. They have shown great potential in veterinary and human medicine for the treatment and prophylaxis of infections.

Effects of nitrogen sources on cell growth and lipid accumulation of green alga Neochloris oleoabundans.

Microalgal lipids are the oils of future for sustainable biodiesel production. However, relatively high production costs due to low lipid productivity have been one of the major obstacles impeding their commercial production. We studied the effects of nitrogen sources and their concentrations on cell growth and lipid accumulation of Neochloris oleoabundans, one of the most promising oil-rich microalgal species.

CO(2) bio-mitigation using microalgae.

Microalgae are a group of unicellular or simple multicellular photosynthetic microorganisms that can fix CO(2) efficiently from different sources, including the atmosphere, industrial exhaust gases, and soluble carbonate salts. Combination of CO(2) fixation, biofuel production, and wastewater treatment may provide a very promising alternative to current CO(2) mitigation strategies.

Biofuels from microalgae.

Microalgae are a diverse group of prokaryotic and eukaryotic photosynthetic microorganisms that grow rapidly due to their simple structure. They can potentially be employed for the production of biofuels in an economically effective and environmentally sustainable manner. Microalgae have been investigated for the production of a number of different biofuels including biodiesel, bio-oil, bio-syngas, and bio-hydrogen.