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The ability of newly isolated bacteria, identified as Bacillus subtilis immobilized on alginate hydrogel beads, to degrade phenol was investigated under different parameters, such as phenol concentration, bead diameter and inoculums size, and was optimized using full factorial design methodology. A mathematical model that governs the degradation of phenol by the immobilized system was obtained and it fitted the experimental data very well. The model indicated that within the range of variables employed, all the parameters and their interactions influenced the biodegradation process, whereby the phenol concentration was the most significant factor. B. subtilis revealed a very high degradation activity and could be grown using phenol as the sole source of carbon. Phenol was degraded by the new bacteria in 8 h under the optimum conditions obtained by the desirability function: 100 mg L-1 phenol concentration, 3 mm beads diameter and 244.5 mg of cell dry per liter biomass size, with a desirability value of 91.25 %.

In this paper, a local isolated yeast strain was studied for bioethanol production using protein-free cheese whey powder (CWP) in batch alcoholic fermentation experiments. Ethanol tolerance tests were performed with different ethanol concentrations (from 0% to 20%). The maximum ethanol tolerance obtained for our strain was 5% (v/v). The influence of initial lactose concentration, temperature and pH on fermentation kinetic was studied. For initial lactose concentration ranging from 57.5 to 260 gL-1, the highest ethanol production 34.8 gL-1 was obtained at 109 gL-1 initial lactose concentration corresponding to 0.413 gg-1 ethanol yield (YP/S); (While it was noticed less ethanol production, namely 0.178 g g-1) at a higher initial whey sugar concentration of 260 gL-1. The effect of the initial pH on the fermentation was studied at three different values: 3, 4 and 5. The ethanol production reached a maximum of 22 g L-1 with a lactose consumption of 77.62% at pH 4. However, an observed decrease occurred in ethanol production and lactose consumption at pH 3, with values of 10.34 gL-1 and 24.46%, respectively. For the fermentation conducted at the three temperatures of 37°C, 40°C and 43°C, the maximum ethanol production and lactose consumption were 34.82 gL-1 and 80.75%, respectively, achieved at 37°C. The experimental data was analyzed using the Gompertz model to obtain the following kinetic parameters: the maximum ethanol concentration (Pm) was found to be 36.97 gL-1, the maximum ethanol production rate (rp,m) was 0.402 gL-1h-1 and the lag phase (tl ) was 10.8 h. The comparison of the isolated Kluyveromyces marxianus TXID4911 strain with the reference strain Kluyveromyces marxianus DSM 5421, showed a relatively close ethanol yield (YP/S) 0.415 and 0.505 gg,-1 respectively [ABSTRACT FROM AUTHOR]

The present study investigates the elaboration and performance of a new Powdered Activated Carbon composite membrane to be used in the elimination of phenol from aqueous solution. The characterization of membranes was determined by Fourier transforms infrared spectroscopy, X-ray diffraction, Thermal gravimetric analysis and Scanning electron microscopy analysis. The effect of treatment, the several parameters such as initial phenol concentration and adsorbent mass have been investigated in batch experiments as well as pH solution on the adsorption process using activated carbon composite membranes. Adsorption isotherm non-linear studies indicate that the Langmuir isotherm provides an adequate fit to the isotherm data. The maximum monolayer adsorption capacity was found 103.08 mg/g. Response surface methodology was used to optimize the adsorption capacity of phenol at equilibrium time and the corresponding operating conditions. The highest adsorption capacity of phenol was theoretically predicted to be 4 mg/g, at which the initial phenol concentration was 20 mg/L, adsorbent dose 0.1 g/L, and agitation speed 250 rpm. [ABSTRACT FROM AUTHOR]

This present study, investigates the performance of activated sardine scale powder (ASSP)/ Cellulose acetate (CA)/Polyvinylpyrrolidone (PVP) and powdered activated carbon (PAC)/ Cellulose acetate (CA) / Polyvinylpyrrolidone (PVP) composites membranes prepared by phase inversion for the elimination of humic substances (HS) from aqueous solutions. The materials and composites membranes were characterized by FTIR, XRD, SEM analyses. Overall, the results exhibit the higher performance of ASSP /CA/PVP composite membrane than PAC /CA/PVP composite membrane for the elimination of humic substances from water. Adsorption isotherm non-linear studies indicated that the two composites membranes can be successfully modeled by the Langmuir, Freundlich, and Temkin. The maximum monolayer adsorption capacity was found to be 31.00 mg/g and 23.32 mg/g for ASSP /CA/PVP and PAC /CA/PVP composites membranes, respectively. ASSP /CA/PVP composite membrane seems to be a promising material for HS removal from aqueous solutions. [ABSTRACT FROM AUTHOR]

The ability ofAspergillus nigerto degrade phenol in an aerobic batch culture was investigated under different parameters such as initial concentration of phenol, pH, and temperature. The results showed thatA. nigercan grow using phenol as the sole source of carbon. A high concentration of phenol (1,000 mg/L) was completely degraded after 140 h atT = 30°C and pH 5.5. The main and the interactive effects of initial phenol concentration (200–1,000 mg/L), pH (2.5–8.5), and temperature (25–35°C) on the biodegradation of phenol were studied in this work. A full factorial design 23was used to determine the optimum conditions for the phenol biodegradation process. The maximum amount of degraded phenol was 1.32 mg/h, achieved at 200 mg/L of initial phenol concentration, pH 8.5, andT = 35°C. [ABSTRACT FROM AUTHOR]

The purpose of this work was to study the phenol elimination by immobilized bacteria cells on a combined material. The immobilization by inclusion ofPseudomonas aeruginosain calcium alginate beads with powdered activated carbon (PAC) allows the adsorption and biodegradation of phenol simultaneously. The full factorial design methodology was carried out to estimate the influence of the considered parameters (initial phenol concentration, amount of PAC, and diameter of beads) on the time of phenol removal. The adsorbent amount was the most significant parameter followed by the initial phenol concentration, while the effect of beads diameter was insignificant. The minimum time of phenol elimination obtained from the optimization procedure was 22.6 h. This optimum was achieved at 5 g/L of PAC and an initial phenol concentration of 100 mg/L. [ABSTRACT FROM AUTHOR]

Indigenous isolated bacterium Aeromonas sp. was immobilized in calcium alginate and the related immobilization parameters like bead diameter, inoculum size and the initial phenol concentration required for biodegradation were determined. The biodegradation activity was most efficient with 4 mm calcium alginate beads. The optimal immobilized biomass required was about 28 109 cells/mL. Compared with free-cell suspensions, the alginate matrix used for immobilization of cells provided better environment for the biodegradation of high phenol concentrations probably due to its protective effect. The alginate immobilized cells provided remarkable performance in experiments using elevated phenol concentrations. [ABSTRACT FROM AUTHOR]