Aerobic biodegradation and inhibition kinetics of poly‐aromatic hydrocarbons (PAHs) in a petrochemical industry wastewater in the presence of biosurfactants

Background The isomers of chlorotoluene (2‐chlorotoluene, 3‐chlorotoluene and 4‐chlorotoluene) are considered to be toxic and to have a negative impact on humans and the environment. Therefore, issues related to their removal from the natural environment have become of increasing interest. Results The morphology of cells and colonies after long‐term metabolic stress was significantly modified. Metabolic stress is suggested to be a determinant of bacteria cell surface properties. The chlorine atom position in chlorotoluenes has a strong impact on cell surface modification. When the chlorine atom was at the ortho or para position, a large increase in hydrophobicity (from 40% to 73% and from 29% to 49%, respectively) and a decrease in the inner membrane permeability (from 0.31 to 0.24 µmol L−1 min−1 and from 0.52 to 0.13 µmol L−1 min−1) were observed. Moreover, Achromobacter sp. KW1 strain was found to exhibit good ability to degrade chlorotoluenes. The greatest difference in biodegradation between the stressed and non‐stressed strains was observed for the cultures grown on 4‐chlorotoluene and 3‐chlorotoluene. Conclusions Both long‐term contact with hydrocarbons and the addition of surfactants demonstrated a beneficial effect on the biodegradation process. However, as a result of long‐term contact with hydrocarbons, the bacteria studied were able to degrade chlorotoluenes faster and more effectively. © 2017 Society of Chemical Industry

Section: Introductionmentioning

confidence: 99%

The ability of Achromobacter sp. KW1 strain to biodegrade isomers of chlorotoluene

Pacholak

Smułek

Jesionowski

et al. 2017

“…Waste motor oil and diesel were used for biosurfactants production. They are stable after incubations up to 100 ∘ C, in the presence of various NaCl concentrations (20-150 g L -1 ) and over a wide pH range (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). The CMC were identical for the two biosurfactants at about 800 mg L -1 .…”

Section: Resultsmentioning

confidence: 93%

“…They contain polcyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons ( n ‐alkanes), and high levels of heavy metals. The PAHs, such as benzo[ a ]pyrene, are well known for their carcinogenicity potential . Considerable quantities of heavy metals, such as Pb, Zn, Cu, Cr, Ni and Cd, are contained in the waste oils; these metals are highly toxic to organisms .…”

Section: Introductionmentioning

confidence: 99%

“…The PAHs, such as benzo[a]pyrene, are well known for their carcinogenicity potential. 6,5 Considerable quantities of heavy metals, such as Pb, Zn, Cu, Cr, Ni and Cd, are contained in the waste oils; these metals are highly toxic to organisms. 5 Leakage of storage tanks and pipelines, land disposal of petroleum wastes, and accidental spills, are the main causes of soil and sea contamination.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Promising abilities of mercapto‐degrading Staphylococcus capitis strain SH6 in both crude oil and waste motor oil as sole carbon and energy sources: its biosurfactant production and preliminary characterization

Chebbi

Hentati

Cheffi

et al. 2018

BACKGROUND It was shown previously that a Staphylococcus capitis strain SH6 was able to degrade several malodorous mercaptans and simultaneously reduce the surface tension. RESULTS This present work revealed the capacity of strain SH6 to grow on various hydrocarbons, used as the only carbon and energy sources. Based on GC–MS analyses, the substantial ability to degrade up to 45% and 64% of aliphatic hydrocarbons (n‐alkanes) of crude oil and waste motor oil, respectively, after 30 days of incubation at 37 °C and 180 rpm, was shown. The properties of biosurfactant produced by strain SH6 grown on different oil substrates (diesel oil and waste motor oil) were studied. Biosurfactants exhibited enhanced emulsification capacities and significant stabilities over a wide range of salinity (20–150 g L‐1), temperature (–20–100 °C), and pH , and also the ability to remove crude oil from contaminated soils. Their critical micelle concentrations (CMC) were of 800 mg L‐1. FTIR analyses suggested the lipopetide nature of biosurfactants. CONCLUSION The stabilities of biosurfactants over a wide pH range, high temperatures and variable concentrations of salt, as well as emulsifying properties, suggest potential applications in bioremediation processes. © 2017 Society of Chemical Industry

“…Activated sludge samples, previously collected from the wastewater treatment plant of a petrochemical industry, were added into an open system continuous full‐mixed tank bioreactor specified by Sponza and Gok . The bioreactor was primarily fed with synthetic wastewater in order to age the wastewater.…”

Section: Methodsmentioning

confidence: 99%

Monitoring of the degradation of aromatic hydrocarbons by bioaugmented activated sludge

Vural

Özdemir

2019

BACKGROUND: The petrochemical industry wastewater contains many organic compounds that are difficult to degrade. The activated sludge system reinforced by bioaugmentation technology represents a more effective alternative to treat industrial wastewater. In this study, bioaugmented activated sludge water demonstrated high efficiency in removing five tested hydrocarbons.RESULTS: Optimized degradation rates were obtained upon inoculation of a continuous bioreactor system with degradative bacteria (Acinetobacter sp., Aeromonas sp., Arthrobacter nicotianae, Burkholderia cepacia, Chryseobacterium sp., Pseudomonas fluorescens, Micrococcus luteus and Raoultella planticola). The addition of a hydrocarbon mixture (terephthalic acid, acenaphthene, fluorene, anthracene, and pyrene) into the bioaugmented sludge resulted in degradation rates equivalent to 97.90%, 99.87%, 98.89%, 97.28%, and 94.55% respectively after 24-48 h incubation. Molecular biomonitoring was performed with real-time quantitative polymerase chain reaction (qPCR). According to the obtained results, the numbers of copy DNA of the degradative bacteria increased by 0.36-1.13 log at the end of the degradation process. The presence of some oxygenase genes (Nah, NidA, Pah Rhd Gr(+), Pah Rhd Gr(−) and C23O), that catabolize aromatic hydrocarbons in activated sludge, were detected by specific primers. CONCLUSION: Bioaugmentation represents a potent and eco-friendly approach that can effectively remove the drastic increase in the concentrations of aromatic hydrocarbons in industrial wastewaters. Molecular biomonitoring during degradation can be considered a rapid and an effective in situ method that quantifies the active microbial population in wastewater. The method provides beneficial information about the composition of microbial community and sustainability of the degradation process. Figure 3. The graphics reveal the alterations in the copy number of DNA of bacterial isolates in bioaugmented sludge during the three stages (n = 3, ± standard deviation). (a-c) The numbers of bacteria at the first, second and third stages and the copy number of DNA in the first, second and third stages, respectively. The copy number of DNA of all bacterial isolates have increased as the concentration of hydrocarbon increased. J Chem Technol Biotechnol 2020; 95: 52-62