Immobilization of Cyclodextrin glycosyltransferase onto three dimensional- hydrophobic and two dimensional- hydrophilic supports: A comparative study.

Cyclodextrin glycosyltransferase (CGTase) degrades starch into cyclodextrin via enzymatic activity. In this study, we immobilize CGTase from Thermoanaerobacter sp. on two supports, namely graphene nanoplatelets (GNP) consisting of short stacks of graphene nanoparticles and a calcium-based two-dimensional metal organic framework (Ca-TMA).

ZIF-8 as support for enhanced stability of immobilized lipase used with a thermoresponsive switchable solvent to simplify the microalgae-to-biodiesel process.

The zeolitic imidazole framework (ZIF)- 8 was tested as a support to enhance the stability of immobilized lipase. The lipase immobilized on ZIF-8, through surface attachment and encapsulation, was used for the simultaneous cell disruption and oil extraction from untreated, wet microalgal paste. The successful attachment of the enzyme to ZIF-8 was confirmed via Fourier-transform infrared spectroscopy.

Immobilization of Lipase from in Magnetic Macroporous ZIF-8 Improves Lipase Reusability in Biodiesel Preparation.

In recent years, metal-organic frameworks (MOFs) have emerged as a promising support for immobilizing enzymes due to their high designability and structural diversity. Previous studies show that MOFs with single-crystal-ordered macroporous structures can effectively improve the accessibility of large-size enzyme and reduce the mass transfer resistance compared to conventional MOFs. In order to further enhance the reusability of lipase immobilized on macroporous MOFs, modification of MOFs through some magnetic particles could be an efficient approach.

Simultaneous Enzymatic Cellulose Hydrolysis and Product Separation in a Radial-Flow Membrane Bioreactor.

Hydrolysis is the heart of the lignocellulose-to-bioethanol conversion process. Using enzymes to catalyze the hydrolysis represents a more environmentally friendly pathway compared to other techniques. However, for the process to be economically feasible, solving the product inhibition problem and enhancing enzyme reusability are essential.

Removal of Bromine from the non-metallic fraction in printed circuit board via its Co-pyrolysis with alumina.

The effectiveness of a recycling approach of the printed circuit board (PCBs), and, thus, the quality of polymeric constituents, primarily rests on the capacity to eliminate the bromine content (mainly as HBr). HBr is emitted in appreciable quantities during thermal decomposition of PCB-contained brominated flame retardants (BFRs). The highly corrosive, yet relatively reactive HBr, renders recovery of bromine-free hydrocarbons streams from brominated polymers in PCBs very challenging.

Advances in Enzyme and Ionic Liquid Immobilization for Enhanced in MOFs for Biodiesel Production.

Biodiesel is a promising candidate for sustainable and renewable energy and extensive research is being conducted worldwide to optimize its production process. The employed catalyst is an important parameter in biodiesel production. Metal-organic frameworks (MOFs), which are a set of highly porous materials comprising coordinated bonds between metals and organic ligands, have recently been proposed as catalysts.

MOFs as Potential Matrices in Cyclodextrin Glycosyltransferase Immobilization.

Cyclodextrins (CDs) and their derivatives have attracted significant attention in the pharmaceutical, food, and textile industries, which has led to an increased demand for their production. CD is typically produced by the action of cyclodextrin glycosyltransferase (CGTase) on starch. Owing to the relatively high cost of enzymes, the economic feasibility of the entire process strongly depends on the effective retention and recycling of CGTase in the reaction system, while maintaining its stability.

Lipase Immobilization on Macroporous ZIF-8 for Enhanced Enzymatic Biodiesel Production.

Immobilization of enzyme on metal-organic frameworks (MOFs) has drawn increasing interest owing to their many well-recognized characteristics. However, the pore sizes of MOFs (mostly micropores and mesopores) limit their application for enzyme immobilization to a great extent owing to the large size of enzyme molecules. Synthesis of MOFs with macropores would therefore solve this problem, typically encountered with conventional MOFs.

Immobilization of formate dehydrogenase in metal organic frameworks for enhanced conversion of carbon dioxide to formate.

Hydrogenation of carbon dioxide (CO) to formic acid by the enzyme formate dehydrogenase (FDH) is a promising technology for reducing CO concentrations in an environmentally friendly manner. However, the easy separation of FDH with enhanced stability and reusability is essential to the practical and economical implementation of the process. To achieve this, the enzyme must be used in an immobilized form.

Using microalgae for remediation of crude petroleum oil-water emulsions.

Crude petroleum oil spills are among the most important organic contaminations. While the separated oils accumulated on the surface water are relatively easily removed, the emulsified portions are more difficult to remove and pose significant threats to the environment. Bioremediation using bacteria has proven to be an effective method, but the biomass produced in this case does not have any significant remunerative value.

Simultaneous and rapid quantification of microalga biomolecule content using electrochemical impedance spectroscopy.

Lipids, proteins, and carbohydrates are the major constituents found in microalga cells, in varying proportions, and these biomolecules find applications in different industries. During microalga cultivation, to efficiently manipulate, control, and optimize the productivity of a specific compound for a specific application, real-time monitoring of these three cell components is essential. In this study, a method using measurement of electrical capacitance was developed to simultaneously determine the lipid, protein, and carbohydrate content of microalga cells without the requirement for any pre-processing steps.

Microalgae cultivation for phenolic compounds removal.

Microalgae are promising sustainable and renewable sources of oils that can be used for biodiesel production. In addition, they contain important compounds, such as proteins and pigments, which have large applications in the food and pharmaceutical industries. Combining the production of these valuable products with wastewater treatment renders the cultivation of microalgae very attractive and economically feasible.

Bilirubin detoxification using different phytomaterials: characterization and in vitro studies.

Background: Activated carbon (AC) is a common adsorbent that is used in both artificial and bioartificial liver devices.

Methods: Three natural materials - date pits of (fruit), (jojoba) seeds, and spp. (microalgae) - were used in the present investigation as precursors for the synthesis of AC using physical activation.

Gold extraction from biosolid sludge obtained by sewage treatment.

Treatment of municipal wastewater, which involves multiple steps, produces large amounts of biosolid sludge, which is either incinerated or disposed in landfills. This sludge contains carbon, nitrogen, and phosphorous in appreciable amounts, and hence, it is being recently suggested that it should be used as a fertilizer. However, the biosolid sludge also contains large amounts of heavy metals, which exert harmful effects on the plantation and therefore, they must be removed before it can be used as a fertilizer.

Effect of Enzymatic pre-treatment of microalgae extracts on their anti-tumor activity.

Background: There is an increasing need to find natural bioactive compounds for pharmaceutical applications, because they have less harmful side effects compared to their chemical alternatives. Microalgae (MA) have been identified as a promising source for these bioactive compounds, and this work aimed to evaluate the anti-proliferative effects of semi-purified protein extracted from MA against several tumor cell lines.

Methods: Tested samples comprised MA cell extracts treated with cellulase and lysozyme, prior to extraction.

Evaluation of an activated carbon packed bed for the adsorption of phenols from petroleum refinery wastewater.

The performance of an adsorption column packed with granular activated carbon was evaluated for the removal of phenols from refinery wastewater. The effects of phenol feed concentration (80-182 mg/l), feed flow rate (5-20 ml/min), and activated carbon packing mass (5-15 g) on the breakthrough characteristics of the adsorption system were determined. The continuous adsorption process was simulated using batch data and the parameters for a new empirical model were determined.

Enzymatic pre-treatment of microalgae cells for enhanced extraction of proteins.

Crude proteins and pigments were extracted from different microalgae strains, both marine and freshwater. The effectiveness of enzymatic pre-treatment prior to protein extraction was evaluated and compared to conventional techniques, including ultrasonication and high-pressure water extraction. Enzymatic pre-treatment was chosen as it could be carried out at mild shear conditions and does not subject the proteins to high temperatures, as with the ultrasonication approach.

RF microalgal lipid content characterization.

Most conventional techniques for the determination of microalgae lipid content are time consuming and in most cases are indirect and require excessive sample preparations. This work presents a new technique that utilizes radio frequency (RF) for rapid lipid quantification, without the need for sample preparation. Tests showed that a shift in the resonance frequency of a RF open-ended coaxial resonator and a gradual increase in its resonance magnitude may occur as the lipids content of microalgae cells increases.

A review of enzymatic transesterification of microalgal oil-based biodiesel using supercritical technology.

Biodiesel is considered a promising replacement to petroleum-derived diesel. Using oils extracted from agricultural crops competes with their use as food and cannot realistically satisfy the global demand of diesel-fuel requirements. On the other hand, microalgae, which have a much higher oil yield per hectare, compared to oil crops, appear to be a source that has the potential to completely replace fossil diesel.

Reduction of COD in refinery wastewater through adsorption on date-pit activated carbon.

Experiments were carried out to evaluate the batch adsorption of COD from petroleum refinery wastewater on a locally prepared date-pit activated carbon (DP-AC), and its adsorption effectiveness was compared to that of commercially available BDH activated carbon (BDH-AC). Adsorption equilibrium and kinetic data were determined for both adsorbents and fitted to several adsorption isotherm and kinetics models, respectively. The Langmuir monolayer isotherm fitted well the equilibrium data of COD on both adsorbents; whereas, the kinetics data were best fitted by the pseudo-second order model.

Assessment of electrocoagulation for the treatment of petroleum refinery wastewater.

Batch electrocoagulation experiments were carried out to evaluate the removal of sulfate and COD from petroleum refinery wastewater using three types of electrodes: aluminum, stainless steel, and iron. The effects of current density, electrode arrangement, electrolysis time, initial pH, and temperature were investigated for two wastewater samples with different concentrations of COD and sulfate. The experimental results indicated that the utilization of aluminum, as anode and cathode, was by far the most efficient arrangement in the reduction of both the contaminants.

The effect of crystallinity of cellulose on the rate of reducing sugars production by heterogeneous enzymatic hydrolysis.

A kinetic model is devised, from the reaction mechanism steps, to predict the rate of reducing sugar production by hydrolysis of two types of cellulose, namely, amorphous carboxymethylcellulose (CMC) and highly crystalline wood shavings, using Aspergillus niger cellulase. Experimental results in a stirred batch reactor at 40 degrees C show that the production of reducing sugar reduced at much shorter times for wood shavings in comparison to CMC at the same initial substrate concentration. The experimental results are used to determine the kinetic parameters of the model equations.

Adsorption of lipase on hollow fiber membrane chips.

The amount of lipase from Mucor miehei adsorption on ultrafiltration polysulfone hollow fiber membrane chips has been determined using different lipase concentrations at three different temperatures, namely 30, 35, and 40 degrees C. It was experimentally shown that adsorption of lipase increases with temperature. The results were used to evaluate the constants found in the Langmuir adsorption isotherm model coupled with the Van't Hoff's relationship.

Production of biodiesel by lipase-catalyzed transesterification of vegetable oils: a kinetics study.

Kinetics of production of biodiesel by enzymatic methanolysis of vegetable oils using lipase has been investigated. A mathematical model taking into account the mechanism of the methanolysis reaction starting from the vegetable oil as substrate, rather than the free fatty acids, has been developed. The kinetic parameters were estimated by fitting the experimental data of the enzymatic reaction of sunflower oil by two types of lipases, namely, Rhizomucor miehei lipase (RM) immobilized on ion-exchange resins and Thermomyces lanuginosa lipase (TL) immobilized on silica gel.