Houria Ouled-Haddar

Biological Removal of the Mixed Pharmaceuticals: Diclofenac, Ibuprofen, and Sulfamethoxazole Using a Bacterial Consortium

Background: The presence of pharmaceuticals at low concentrations (ng to μg) in the environment has become a hot spot for researchers in the past decades due to the unknown environmental impact and the possible damages they might have to the plantae and fauna present in the aquatic systems, as well as to the other living organisms. Objectives: The aim of the present investigation was to develop a bacterial consortium isolated from different origins to evaluate the ability of such a consortium to remove a mixture of pharmaceuticals in the batch system at lab scale, as well as assessment of its resistance to the other micropollutants present in the environment. Material and Methods: Using a closed bottle test, biodegradation of the mixed pharmaceuticals including Diclofenac (DCF), Ibuprofen (IBU), and Sulfamethoxazole (SMX) (at a concentration of 3 mg.L-1 of each drug) by the bacterial consortium was investigated. The test was carried out under metabolic (pharmaceutical was used as the sole source of carbon) and co-metabolic condition (in the presence of glucose). Finally, the ability of the bacterial consortium to resist other micropollutants like antibiotics and heavy metals was investigated. Results: Under the metabolic condition, the mixed bacteria (i.e., consortium) were able to metabolize 23.08% and 9.12% of IBU, and DCF at a concentration of 3 mg.L-1 of each drug, respectively. Whereas, in co-metabolic conditions, IBU was eliminated totally, in addition, 56% of the total concentration of DCF was removed, as well. In both metabolic and cometabolic conditions, removal of SMX was not observed. The selected bacteria were able to resist to most of the applied antibiotics and the used heavy metals, except mercury, where only one strain (S4) was resistant to the later heavy metal. Conclusion: Results suggest that the developed consortium might be an excellent candidate for the application in the bioremediation process for treating ecosystems contaminated with the pharmaceutical.

The RadioP1 – An Integrative Web Resource for Radioresistant Prokaryotes

The extremely radioresistant eubacterium Deinococcus radiodurans and the phenotyp‐ ically related prokaryotes, whose genomes have been completely sequenced, are presently used as model species in several laboratories to study the lethal effects of DNA-damaging and protein-oxidizing agents, particularly the effects of ionizing radiation (IR). Unfortunately, providing relevant information about radioresistant prokaryotes (RP) in a neatly centralized and organized manner still remains a need. In this study, we designed RadioP1 Web resource (www.radiop.org.tn) to gather information about RP defined by the published literature with specific emphasis on (i) predicted genes that produce and protect against oxidative stress, (ii) predicted proteins involved in DNA repair mechanisms and (iii) potential uses of RP in biotechnology. RadioP1 allows the complete RP proteogenomes to be queried using various patterns in a user-friendly and interactive manner. The output data can be saved in plain text, Excel or HyperText Markup Language (HTML) formats for subsequent analyses. Moreover, RadioP1 provides for users a tool “START ANALY‐ SIS”, including the previously described R-packages “drc” and “lethal”, to generate exponential or sigmoid survival curves with D10 and D50 values. Furthermore, when accessible, links to external databases are provided. Supplementary data will be included in the future when the sequences of other RP genomes will become available.

Toxicity assessment of Diclofenac and its biodegradation metabolites toward mice

Biodegradation of the anti-inflammatory drug Diclofenac (DCF) was studied using Enterobacter cloacae (D16) isolated from household compost. This isolate was able to eliminate 67.57% of DCF as sole carbon source after 48 h of incubation. Parallel to its disappearance, five metabolites were observed in microbial active samples which were suspected to be the DCF metabolites. GCMS showed a very similar spectrum of these metabolites with the MS spectrum of the parent compound. DCF Toxicity at different concentrations (toxic dose, therapeutic dose, and low dose) and its metabolites toxicity toward mice liver cells were evaluated. At toxic and therapeutic doses DCF had a negative effect on the oxidative stress parameters represented by a decrease in Reduced Glutathione reserve, lipid peroxidation and a disturbance of the liver detoxification enzymes (superoxide dismutase, Catalase, and glutathione S-transferase). In contrast, no effect was observed after treatment of animals with low dose and DCF biotransformation products.

Valorisation of Date Waste for the Production of Probiotic Bacterial Biomass = Valorisation de Dechets de Datte Pour la Production de la Biomasse Probiotique Bacterienne

This study aimed to valorise date waste by improving biomass production of Lactobacillus plantarum G1 using date juice as carbon source. The physicochemical analysis indicated that the date juice contained a high amount of sugars easily assimilated which make it favorable for the growth of the bacterial strain. The results showed that the date juice with 12% of total sugar supplemented with salts and organic nitrogen found in MRS medium produced a higher biomass yield when compared to biomass production in MRS medium and in date juice alone. Plackett-Burman statistical experimental design was used to screen the most important nutrients influencing lactic acid biomass production. Seven variables including date extract were screened for their effect on Lactobacillus plantarum biomass production. Results from this analysis demonstrated that the date extract, yeast extract and peptone were the most significant factors.