Raja Ben Amar

Enzymatic hydrolysis of cuttlefish (Sepia officinalis) and sardine (Sardina pilchardus) viscera using commercial proteases: effects on lipid distribution and amino acid composition.

Total lipid and phospholipid recovery as well as amino acid quality and composition from cuttlefish (Sepia officinalis) and sardine (Sardina pilchardus) were compared. Enzymatic hydrolyses were performed using the three proteases Protamex, Alcalase, and Flavourzyme by the pH-stat method (24 h, pH 8, 50 degrees C). Three fractions were generated: an insoluble sludge, a soluble aqueous phase, and an oily phase. For each fraction, lipids, phospholipids, and proteins were quantified. Quantitative and qualitative analyses of the raw material and hydrolysates were performed. The degree of hydrolysis (DH) for cuttlefish viscera was 3.2% using Protamex, 6.8% using Flavourzyme, and 7% using Alcalase. DH for sardine viscera was 1.9% (using Flavourzyme), 3.1% (using Protamex) and 3.3% (using Alcalase). Dry matter yields of all hydrolysis reactions increased in the aqueous phases. Protein recovery following hydrolysis ranged from 57.2% to 64.3% for cuttlefish and 57.4% to 61.2% for sardine. Tissue disruption following protease treatment increased lipid extractability, leading to higher total lipid content after hydrolysis. At least 80% of the lipids quantified in the raw material were distributed in the liquid phases for both substrates. The hydrolysed lipids were richer in phospholipids than in the lipids extracted by classical chemical extraction, especially after Flavourzyme hydrolysis for cuttlefish and Alcalase hydrolysis for sardine. The total amino acid content differed according to the substrate and the enzyme used. However, regardless of the raw material or the protease used, hydrolysis increased the level of essential amino acids in the hydrolysates, thereby increasing their potential nutritional value for feed products.

Elaboration of new ceramic microfiltration membranes from mineral coal fly ash applied to waste water treatment

This work aims to develop a new mineral porous tubular membrane based on mineral coal fly ash. Finely ground mineral coal powder was calcinated at 700 degrees C for about 3 h. The elaboration of the mesoporous layer was performed by the slip-casting method using a suspension made of the mixture of fly-ash powder, water and polyvinyl alcohol (PVA). The obtained membrane was submitted to a thermal treatment which consists in drying at room temperature for 24 h then a sintering at 800 degrees C. SEM photographs indicated that the membrane surface was homogeneous and did not present any macrodefects (cracks, etc...). The average pore diameter of the active layer was 0.25 microm and the thickness was around 20 microm. The membrane permeability was 475 l/h m(2) bar. This membrane was applied to the treatment of the dying effluents generated by the washing baths in the textile industry. The performances in term of permeate flux and efficiency were determined and compared to those obtained using a commercial alumina microfiltration membrane. Almost the same stabilised permeate flux was obtained (about 100 l h(-1)m(-2)). The quality of permeate was almost the same with the two membranes: the COD and color removal was 75% and 90% respectively.

Hybrid coagulation/membrane process treatment applied to the treatment of industrial dyeing effluent

AbstractA combined system of coagulation and membrane processes was investigated in this study for reactive dyeing wastewater treatment. Microfiltration (MF) and ultrafiltration (UF) membranes were tested in order to study the effect of the membrane type on the hybrid system performances. Additionally, membrane resistance analyses were conducted in order to understand the membrane fouling mechanism. Two different coagulants were used: Al2(SO4)3(Alum) and Amerfloc445. The influence of the coagulation conditions including coagulant nature and shear rate and duration on the UF behavior was studied. Indeed, a procedure of flocs breakage–reformation under different shear intensities was followed in the coagulation step, during these tests, flocs size and sensitivity to breakage as well as their regrowth ability were examined. The filtration results indicated that the coagulation step did not enhance the MF performances. The coagulation/ultrafiltration system was found to be better not only in term of permeate ...

Fluoride removal from aqueous solution by Purolite A520E resin: kinetic and thermodynamics study

AbstractFluoride in drinking water above permissible level causes dental and skeletal fluorosis. Fluoride removal operations have been conducted first on a “model” water solution (i.e. distilled) in which the fluoride concentration has been varied, and second on underground water (Louza 2) using the Purolite A520E resin. Batch sorption studies were carried out to determine the effect of initial fluoride concentration, agitation time, adsorbent dose, co-ions, and temperature on the removal of fluoride by the resin. The amount of fluoride ions removed per unit mass of Purolite A520E resin, at 30°C from 5 mg L−1 fluoride ion solution, was estimated to be 2 mg g−1. The experimental data fitted well to the Langmuir and Freundlich isotherms. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° were calculated, indicating that the adsorption process was spontaneous and endothermic. The fluoride content was reduced to 1.20 from 3.39 mg L−1 by treating Louza 2 water with the Purolite A520E resin (2 g L−1, shaking ti...

Surface modification of microfiltration ceramic membrane by fluoroalkylsilane

ABSTRACTMembrane separation performances regarding selectivity and permeate flux depend on the membrane texture and chemical composition of the material used for membrane elaboration. The surface properties of composite microfiltration membrane zirconium/mud of hydrocyclone laundries of phosphates with average pore diameter of 0.2 μm was chemically modified to change its hydrophilic feature into hydrophobic by grafting 1H,1H,2H,2H—perfluorodecyltriethoxysilane molecule (C8). Observation by scanning electron microscopy showed a sharp decrease of the grafted membrane pore size. Thermogravimetric analysis was used as a technique to identify the grafted silane groups. IR analysis allowed qualitative identification of the presence of link characteristics of incorporated silanes. The determination of the contact angle on the grafted membrane surface proved the hydrophobic character since its value increases from 25° to more than 150°, respectively before and after grafting. The membrane permeability using disti...

Optimization of peptide production by enzymatic hydrolysis of tuna dark muscle by-product using commercial proteases

A protein hydrolysate was prepared from proteins of tuna dark muscle by-product. The hydrolysis conditions (time, temperature, pH and enzyme concentration) using Alcalase and Neutrase were optimized by response surface methodology (RSM). The regression coefficient close to 1.0, observed during experimental and validation runs, indicated the validity of the model. The hydrolysate produced under the optimum conditions determined by RSM using Alcalase, had a low rate of peptide fraction of molecular weight of 1-4 kDa. Meanwhile, the results obtained by hydrolysis under optimal conditions determined by a complementary study (temperature 55°C, time 60 min, 1% enzyme concentration and pH 8.5) show that the hydrolysate produced had a high rate of the peptide fraction of molecular weight of 1-4 kDa. The amino acid composition of the protein hydrolysate prepared proved to have the potential for application as an ingredient in balanced fish diets and as a source of nitrogen in microbial growth media. Keywords : Alcalase, neutrase, tuna dark muscle, RSM, optimization, protein hydrolysate, peptides, degree of hydrolysis African Journal of Biotechnology Vol. 12(13), pp. 1533-1547

Preparation and characterization of carbon microfiltration membrane applied to the treatment of textile industry effluents

ABSTRACT Two tubular carbon microfiltration membranes have been prepared using mineral coal powder under similar conditions onto graphite supports made from carbon powder of 25 and 44 µm and having a porosity and mean pore diameter of 34% and 37% and 1.7 and 3.0 µm, respectively. The mean pore diameters were of 0.5 and 0.8 µm, respectively. The performances depend on the membrane pore diameter. Particularly, the membrane presenting the largest pore size reached a stabilized permeate flux at 1 bar of 150 L/h.m2 against 4.5 L/h.m2 for the membrane of 0.5 µm. However, both membranes showed similar efficiency in term of pollutant removal, which was found independent of transmembrane pressure.

Optimization of Common Cuttlefish (Sepia officinalis) Protein Hydrolysate Using Pepsin by Response Surface Methodology

Protein hydrolysate was prepared from common cuttlefish (Sepia officinalis) by pepsin. Hydrolysis conditions (time, temperature, and enzyme activity) were optimized by response surface methodology (RSM) using a factorial design. The regression coefficient was close to 0.999, observed during both experimental and validation runs, and indicated the validity of the prediction model. An enzyme activity to substrate ratio (X1), 0.04 AU/g protein; time (X2), 85 min; and temperature (X3), 45°C were found to be the optimum conditions for a higher degree of hydrolysis (21%) and nitrogen recovery (90%) using pepsin. According to amino acid analysis results and chemical score, methionine and histidine are the limiting amino acids in the hydrolysates, in that order. All other amino acids are present in sufficient quantity as required.

Surfactants role in the enhancement of the treatment efficiency of the dyeing effluents with combination of membrane processes

AbstractThe industrial process of reactive dyeing of cotton is a sequence of several operations. Different types of surfactants were used several times during the dyeing process; anionic, nonionic, and cationic. The dyeing effluent is heavily charged with pollution especially color and salt. In a treatment at source approach, the dyeing effluent was isolated and then mixed with the other baths containing surfactants. A combined treatment involving microfiltration (MF), as pretreatment followed by nanofiltration (NF) as mean treatment, was investigated. The mixing of the dyeing bath with another effluent showed 100% of MF flux improvement, but the color retention still higher for the single dyeing bath. The NF treatment produces a completely discolored effluent with 100% of suspended solids retention, while the chlorides removal did not exceed 50%.

Production of Interesting Peptides Fractions by Enzymatic Hydrolysis of Tuna Dark Muscle By-product Using Alcalase

ABSTRACT A protein hydrolysate was prepared from proteins of tuna dark muscle by-product. The hydrolysis conditions (time, temperature, pH, and enzyme concentration) using Alcalase was optimized by response surface methodology (RSM). The regression coefficient close to 1.0, observed during experimental and validation runs, indicated the validity of the model. The hydrolysate produced under the optimum conditions determined by RSM has a low rate of peptide fraction of molecular weight of 4–1 kDa. Meanwhile, the results obtained by hydrolysis under optimal conditions determined by a complementary study (temperature 55°C, time 60 min, 1% enzyme concentration, and pH 8.5) show that the hydrolysate produced has a height rate of the peptide fraction of molecular weight of 4–1 kDa. The amino acid composition of the protein hydrolysate prepared proved to have the potential for application as an ingredient in balanced fish diets and as a source of nitrogen in microbial growth media.