Nour Sh. El-Gendy

Design and Optimization of a Process for Sugarcane Molasses Fermentation by Saccharomyces cerevisiae Using Response Surface Methodology

A statistical model was developed in this study to describe bioethanol production through a batch fermentation process of sugarcane molasses by locally isolated Saccharomyces cerevisiae Y-39. Response surface methodology RSM based on central composite face centered design CCFD was employed to statistically evaluate and optimize the conditions for maximum bioethanol production and study the significance and interaction of incubation period, initial pH, incubation temperature, and molasses concentration on bioethanol yield. With the use of the developed quadratic model equation, a maximum ethanol production of 255 g/L was obtained in a batch fermentation process at optimum operating conditions of approximately 71 h, pH 5.6, 38°C, molasses concentration 18% wt.%, and 100 rpm.

Biodegradation of Baleym Mix Crude Oil in Soil Microcosm by Some Locally Isolated Egyptian Bacterial Strains

Petroleum refining, transportation and storage are sources of soil contamination. In Egypt, a large number of contaminated sites exist as a result of different crude oil activities. In this work, biodegradation experiments in artificially oil contaminated soil microcosms (30 cm × 26 cm × 8 cm) of shallow polypropylene plastic trays were carried out with special emphasis on biodegradation of polycyclic aromatic hydrocarbons (PAHs). Two promising isolates, Pseudomonas aeruginosa I.1.1.6 and Brevibacterium casei I.2.1.7, previously isolated from Egyptian hydrocarbon contaminated soil, were used. The microcosms were inoculated at 30°C for 60 days with a water content of 60%wt. TPH were quantitatively monitored, gas chromatographic (GC) and high performance liquid chromatographic (HPLC) analysis were preformed to follow up the biodegradation process. The results obtained indicate that after 60 days of incubation; Pseudomonas aeruginosa I.1.1.6 showed higher TPH biodegradation efficiency (64%) than that of Brevibacterium casei I.2.1.7 (58%). Bacterial isolates I.1.1.6 and I.2.1.7 showed total normal alkanes degradation of approximately 74% and 90%, respectively. Generally they are capable of degrading high molecular weight PAHs (five and six membered ring compounds, benzo[b]fluoranthene; BbF and indeno[1,2,3-cd]Pyrene, IP, and have broad versatility in their action on the16PAH compounds currently regulated by the US Environmental Protection Agency (EPA) as priority pollutants, and could be useful in bioremediation of soil contaminated with crude oil.

Degradation of Asphaltenic Fraction by Locally Isolated Halotolerant Bacterial Strains

Three halotolerant bacterial species were isolated from locally oil-polluted water sample for their ability to utilize asphaltene (Asph) fraction as sole carbon and energy source. These bacteria degrade 83–96% of 2500 mg/L asphaltene within 21 d at 3 0 ∘ C and pH7. They were identified as Bacillus sp. Asph1, Pseudomonas aeruginosa Asph2, and Micrococcus sp. Asph3. A statistically significant difference at 95% confidence level for cell growth and percentage biodegradation (%BD) was observed in all biotreatment flasks relative to noninoculated (–ve control) flasks. Regression analysis estimated a quadratic polynomial equation for Asph biodegradation as a function of cell growth. Gel permeation chromatographic (GPC) and Fourier transform infrared (FT-IR) analysis revealed decrease in Asph average molecular weights and significant alternations in functional groups after biotreatment, respectively.

Kinetic Modeling and Error Analysis for Decontamination of Different Petroleum Hydrocarbon Components in Biostimulation of Oily Soil Microcosm

A microcosm study was constructed to investigate the effect of complex co-substrate (corn steep liquor, CSL) addition on indigenous bacterial community, rate and extent of petroleum hydrocarbons (PH) degradation in an oily soil with total petroleum hydrocarbons (TPH) content of 63353 mg kg−1. TPH degradation was found to be characterized by a rapid phase of degradation during the first three weeks where 76% removal of TPH occurred, followed by a slower degradation phase, where further 7% of the initial TPH was removed by the end of incubation period, 35 d. Branched alkanes are more resistant to microbial degradation than n-alkanes. Furthermore, the unresolved complex mixtures (UCM) of hydrocarbons are less degradable than n- and iso-alkanes. Pristane (Pr) was the most recalcitrant aliphatic compound studied in this work. These results in addition to the extensive bacterial growth observed (from 107 to 1010 CFU g−1 soil) give strong support that the addition of CSL resulted in increased degradation rates. The indigenous bacteria grew exponentially during the incubation period of 35 d with a growth rate of 0.26 d−1. Kinetic modeling was performed to estimate the rates of biodegradation of each hydrocarbon type component in the studied system. Five different error functions were used in this study to evaluate the fitness of the model equation to the obtained experimental data. This showed that the degradation of ∑nC20-nC24, ∑nC35-nC42 and nC18 can be better represented by a second order model, whereas the TPH, total resolvable peaks (TRP), nC17, UCM, ∑nC10-nC14, ∑nC15-nC19, ∑nC25-nC29, ∑nC30-nC34, ∑nCn, and ∑isoCn and isoprenoids Pr and phytane (Ph) were similarly following the first order model.

Effect of different bioremediation techniques on petroleum biomarkers and asphaltene fraction in oil-polluted sea water

AbstractThe present study has clearly demonstrated that seeding a petroleum hydrocarbon polluted sea water with a halotolerant Pseudomonas aeruginosa Asph2 and corn steep liquor as a cheap and readily available source of nutrients significantly enhances the progress of biodegradation BD of petroleum hydrocarbon pollutants. There was a statistically high significant difference between natural weathering NW and both bioaugmentation BA (p = 2.92e-14) and biostimulation BS (p = 3.56e-13) at 95% confidence interval (α = 0.05). BA significantly improved the efficiency of total petroleum hydrocarbon TPH and the recalcitrant asphaltene degradation by ≈ 23 and 17% compared to BS process (p = 2.0693e-5 and p = 1.4e-3, respectively). The BD of biomarkers; pristane Pr, phytane Ph, and terpanes were very apparent. The BD of C28 tricyclic terpane, C27 13β, 17α- diasterane (20S), and C30 17α, 21β-hopane were higher than that of C35 17α,21β-homohopane. The BD of C27 18α(H)-22,29,30-trisnorneohopane (Ts) was higher than t...

Kinetic evaluation and modeling for batch degradation of 2-hydroxybiphenyl and 2,2′-dihydroxybiphenyl by Corynebacterium variabilis Sh42

abstract This study evaluated the biodegradation kinetics of 2-hydroxybiphenyl (2-HBP) and 2,2′-dihydroxybiphenyl (2,2′-DHBP) with different initial concentrations range S 0 (5–50 mg/L) using suspended cultures of Corynebacterium variabilis Sh42 with fixed initial biomass concentration X 0 (315.8 mg/L) in a series of batch experiments. The cultures followed substrate inhibition kinetics. By fitting specific growth rates μ (h−1) on suitable substrate inhibition models, biokinetic constants that are necessary to understand the kinetics of biodegradation process were evaluated by POLYMATH 6.1 software. Although Haldane and Yano and Koga (2) biokinetic equations for substrate inhibition seem to be the best adequate expressions for specific growth rates on 2-HBP and 2,2′-DHBP, respectively, an evident disagreement was observed between experimental and simulated profiles for bacterial growth X (mg/L) and substrate concentration S (mg/L). Correlation and simulation studies using a new proposed model based on mod...

Green synthesis of α-Fe2O3 using Citrus reticulum peels extract and water decontamination from different organic pollutants

ABSTRACT In this study, α-Fe2O3 nanoparticles (NPs) have been prepared using the hot water extract of the mandarin (Citrus reticulum) peels as a way for recycling of domestic waste to valuable product. The prepared hematite was characterized by UV/Vis spectroscopy, thermal gravimetric analysis, XRD, FTIR, SEM, and TEM. It was found to be porous irregular sphere shaped NPs with average size of 20–63 nm, characterized by weak ferromagnetic properties and band gap (Eg) of 2.38 eV. The prepared α-Fe2O3 NPs expressed good photocatalytic degradation activity. It showed good capacity for the decontamination of polluted water from anionic and cationic dyes and dicholorophenols under visible light irradiation.

Optimization of Libyan Crude Oil Biodegradation by Using Solid Waste Date as a Natural Low-Cost Material

The objective of this research was to evaluate the effectiveness of the use of solid waste date (SWD) as a lowcost natural agro-industrial materials, in improving crude oil biodegradation in contaminated sea water. Two types of Libyan crude oil (heavy crude oil (HCO) and light crude oil (LCO)) were used in this study. Batch reactors with sea water were used as bioreactors. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationship between operating variables, including HCO and LCO initial concentrations, SWD dosage, and incubation time, to determine the optimum operating conditions. Quadratic models of both CO biodegradation (%) were significant with very low probability values (<0.0001). The results indicated that under optimum operational conditions (i.e, SWD dosage of 0.21g/L in 11dayes for HCO and 0.20 g/L in 14 days for LCO), the best biodegradation efficiency of HCO and LCO were 79.49% and 94.15%, respectively. The predicted results of 82.10% and 95.45% fitted well with experimental results (HCO and LCO removal rates of 97.05% and 99.10%, respectively). Based on removal rates of 5.5% and 14.7% for both HCO and LCO without SWD, respectively, in 28 days, the obtained results revealed that SWD was very efficient in improving the biodegradation of high-concentration crude oils that contaminate sea water.

Application of Response Surface Methodology to Enhance Phenol Removal from Refinery Wastewater by Microwave Process

Phenol contaminated petroleum refinery wastewater presents a great threat on water resources safety. This study investigates the effect of microwave irradiation on removal of different concentrations of phenol in an attempt for petroleum refinery wastewater treatment. The obtained results show that the MW output power and irradiation time have a significant positive effect on the removal efficiency of phenol. The kinetic reaction is significantly affected by initial MW output power and initial phenol concentrations. Response surface methodology (RSM) was employed to optimize and study the interaction effects of process parameters: MW output power, irradiation time, salinity, pH, and H2O2 concentration using central composite design (CCD). From the CCD design matrix, a quadratic model was considered as an ultimate model (2 = 0.75) and its adequacy was justified through analysis of variance (ANOVA). The overall reaction rates were significantly enhanced in the combined MW/H2O2 system as proved by RSM. The optimum values for the design parameters of the MW/H2O2 process were evaluated giving predicted phenol removal percentage of 72.90% through RSM by differential approximation and were confirmed by experimental phenol removal of 75.70% in a batch experiment at optimum conditions of 439 W MW power, irradiation time of 24.22 min, salinity of 574 mg/L, pH 5.10, and initial H2O2 concentration of 10% (v/v).

Evaluation of a bioslurry remediation of petroleum hydrocarbons contaminated sediments using chemical, mathematical and microscopic analysis

This paper concerns the bioremediation of three petroleum hydrocarbon polluted sediment samples collected from the Gulf of Suez, Egypt. The study used a bioslurry system inoculated with Staphylococcus gallinarum NK1, which showed good bioremediation capability regardless of the type of pollutant hydrocarbon and its concentration.