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Biodegradation of UV light treated plastic waste using local bacterial isolates Full text
2024
Sabei, Ansam | Gatea, Iman | Mousa, Nibal | Abbas, Adnan | Ojaily, Gameela | Tawfeeq, Rana | Abid, Ameena
Environmental threats from the accumulation of plastic trash are getting worse. It is robust, lightweight, corrosion-resistant, affordable, and durable. Microorganisms play a significant role in protecting our environment by degrading plastic wastes that are harmful either naturally or by chemical modification. The current study aims to investigate the biodegradation of synthetic polyethylene through the utilization of a laboratory bioreactor. Various types of additives were introduced to the soil samples before subjecting them to a 30-day UV treatment. The degradation of polyethylene was shown through a reduction in weight following a 24-week incubation period with certain bacterial strains. Experimental findings have revealed that models subjected to UV radiation exhibit the highest degree of vulnerability and degradation. Approximately 52% of polyethylene (PE) films underwent degradation when exposed to soil enhanced with peat moss. In contrast, only 40% and 45% of PE films were destroyed when subjected to garden soil that was untreated and treated with UV radiation, respectively. In contrast, the addition of husk resulted in a 48% to 53% reduction in weight for PE films that were buried for the same duration of the experiment. The highest level of effectiveness was achieved by the disintegration of the plastic material that was introduced into the soil along with organic fertilizers, resulting in a value of 56.60%. The weight loss outcomes have been substantiated by the utilization of the Atomic Force Electron Microscope (AFM) images, which exhibited the highest magnitude in the experimental model using soil supplemented with fertilizers.
Show more [+] Less [-]First Report of Enterobacter hormaechei Isolated from Agricultural Soil in the Biodegradation of Glyphosate Full text
2024
Badani, Hadjer | Haddad, Fatma Zohra | ElOuissi, AbdElKader
Several studies have explored the utilization of soil microorganisms, to address the environmental issues associated with glyphosate use and enhance crop yields. In our investigation, screening on Agar plate and broth medium Luria Bertani was carried out after isolating bacterial strains from rhizospheric agricultural soil in Mascara, Algeria, to biodegrade glyphosate, following that by testing the Plant Growth-Promoting Rhizobacteria and evaluate the effects of glyphosate on these proprieties. Our findings indicate that five bacterial strains exhibited growth in the presence of glyphosate concentrations up to 25 mg/ml, beyond this concentration the strains have developed tolerance. Following a partial examination of the 16S rRNA sequences, the bacterial strains were identified as belonging to the genus of Enterobacter. After 10 days of incubation with the glyphosate, Phosphate solubilization decreased in broth and agar Pikovskaya medium and the bacterial strains synthetized less of indole-3-acetic acid compared to the control, indicating the impact of glyphosate on these outcomes, high concentration of glyphosate inhibited nitrogen fixation, and various doses of glyphosate were found to restrict the growth of biofilms in these strains. The results of HPLC examination of secondary metabolites revealed that the primary degradation products of glyphosate in all strains were Sarcosine and Glycine. So, it seemed that the strain could both biodegrade glyphosate and use it for growth ,while also possessing rhizobacteria properties that promote plant development, enabling the use of the strains in the bioremediation of glyphosate-contaminated soils.
Show more [+] Less [-](Bio)degradation of biopolymer and biocomposite in deep-sea environments Full text
2024
Chamley, Alexandre | Baley, Christophe | Gayet, Nicolas | Sarrazin, Jozee | Fuchs, Sandra | Freyermouth, Floriane | Davies, Peter
In order to reduce the contamination of marine ecosystems by plastic materials, the scientific community is engaged in the development of biodegradable substitutes for conventional plastics. While certain candidates have been successfully tested in coastal marine environments, the degradation process in deep-sea environments remains poorly understood. This study examined the degradation of two industrial biopolyesters, a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and a polybutylene-succinate (PBS), in two deep marine environments of the Middle and Eastern Atlantic, at depths of 780 and 1740 m, as well as under laboratory conditions under hydrostatic pressure and without micro-organisms. The findings reveal a considerable biodeterioration of PHBV and a pronounced influence of flax fibre reinforcement on the degradation mechanisms. Conversely, PBS exhibits minimal to no indications of degradation. Additionally, the results confirm that biotic factors are the primary determinants of the degradation processes, with no degradation observed under abiotic conditions.
Show more [+] Less [-]Enhanced Phenanthrene Biodegradation by Bacillus brevis Using Response Surface Methodology Full text
2024
Kiran Bishnoi, Pushpa Rani and Narsi R. Bishnoi
The current investigation assessed the capability of a well-adapted and enriched bacterial strain known as Bacillus brevis for the biodegradation of phenanthrene. To enhance the removal efficiency of phenanthrene, employed Response Surface Methodology (RSM) in conjunction with a Box-Behnken design (BBD) model. The experiments were designed to explore the impact of pH (6.0 to 9.0), temperature (20 to 40°C), initial phenanthrene concentration (50 and 100 ppm), and incubation time (7 to 21 days) on biodegradation of phenanthrene. The highest level of phenanthrene biodegradation, approximately 55.0%, was achieved by Bacillus brevis when the optimal conditions were met as pH of 7.0, temperature 30oC, and initial phenanthrene concentration (70 ppm) after 21 days of incubation time. This study underscores the significance of employing statistical tools like RSM to enhance the microbial degradation of contaminants.
Show more [+] Less [-]PAHs Biodegradation by Locally Isolated Phanerochaete chrysosporium and Penicillium citrinum from Liquid and Spiked Soil Full text
2024
Kiran Bishnoi, Pushpa Rani, Minakshi Karwal and Narsi R. Bishnoi
In the present study, biodegradation of polycyclic aromatic hydrocarbons (PAHs) was examined using two fungal strains, namely P. chrysosporium and P. citrinum, isolated from locally contaminated soil. These two fungal strains were compared based on degradation properties under standardized conditions (pH 7.0, temperature 30oC, carbon source yeast extract) using PAH sole and a mixture of five different PAHs. In liquid media, PAH degradation was higher as compared to spiked soil by P. chrysosporium, followed by P. citrinum. In liquid culture, maximum degradation was 96.13% phenanathrene, 86.34% fluoranthene, 72.75% pyrene, 52.25% chrysene, and 40.16% benzo(a)pyrene by P. chrysosporium. PAH degradation in spiked soil was 78.5% phenanthrene, 65.91% fluoranthene, 61.73% pyrene, 48.2% chrysene, and 26.82% benzo(a)pyrene within 28 days by P. chrysosporium. Both local fungal isolates showed potential for degradation of PAHs alone and in PAH mixtures.
Show more [+] Less [-]Selection of White-Rot Fungi for Decolorization of Palm Oil Mill Effluent and Evaluation of Biodegradation and Biosorption Processes Full text
2024
Sanhathai Ridtibud, Nuttika Suwannasai, Apichaya Sawasdee, Verawat Champreda, Cherdchai Phosri, Sarper Sarp, Nipon Pisutpaisal and Siriorn Boonyawanich
Ten species of white-rot fungi were evaluated for their ability to decolorization of palm oil mill effluent. The highest decolorization efficiency was found with Trametes elegans (PP17-06), followed by Ganoderma sp.2 (PW17-06) and Ganoderma sp.2 (PW17-177), respectively. T. elegans was further evaluated for the long-term performance of decolorization for 24 d. The optimal retention time for the decolorization was 8 d, with a color removal efficiency of 47.7%. Beyond 18 d of incubation, decolorization efficiency was reduced due to the autolysis of enzymes. During the biodegradation process, manganese peroxidase enzyme activities reached a maximum of 36.03 U.L−1. However, no significant laccase and lignin peroxidase activities were observed. T. elegans was also assessed for decolorization performance through biosorption on mycelial biomass. The synthesis of the enzyme was prevented by exposing the mycelium to HgCl2. Within an optimal contact time of 2 d, decolorization efficiency reached 12.5% with ADMI reduction from 4259.0 (±20.1) ADMI to 3727 (±104.04) ADMI. Results indicate that the adsorption capacity was reached at this time, and no significant color removal can be achieved by biomass. Results obtained in this study showed the potential of T. elegans in decolorizing palm oil mill effluent.
Show more [+] Less [-]Prediction and Comparison of Nonlinear Mathematical Models for the Biodegradation of Two Herbicides Under the Effect of Manure in Soils Full text
2024
Cheloufi R,, Alayat H. and Messaadia H.
The study was for the comparison and to know the choice of Models of appreciation of the mineralization of the two herbicides under the effect of two manures (cattle and sheep) in two agricultural soils of different textures. During this work, we used two types of manure, cattle F1 and sheep F2 with two doses. The application of respirometry for monitoring biological activity has been conducted in the laboratory. The treatments were measured for carbon-labeled herbicides released (14CO2) after 1, 3, 7, 14, 28, 42, 60, 90, 120 and 150 days of incubation. Non-linear mathematical models have been developed for the study of the kinetics of the mineralization of herbicides under the effect of manures. The selection criteria for these fit models are R² and RMCE. The comparison of six models stated to choose the single-compartmental model to a first-order ascending exponential that best fits the experimental data. These models show a strong positive correlation between labeled carbon and the biodegradation time of herbicides, especially in clay-textured soil.
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