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Meloidogyne javanica is considered as the most damaging nematode of vegetables in Morocco. Eco-friendly bionematicides are urgently required for its control. In vitro experiments were carried out to assess the direct effect of bioproducts of Peganum harmala against M. javanica. The bioassay showed extracts to be nematotoxic. Aqueous extracts of P. harmala exhibited reversible nematostatic activity. The estimated ID50 of the most active product in methanolic extracts was 368ppm. HPLC-MS of the methanolic extract revealed that total content of major alkaloids of P. harmala was approximately 12.162±0.637mg/g. Harmine (8.514±0.521mg/g) is the dominant alkaloid. In conclusion, Peganum harmala has a reversible nematostatic activity on second stage juveniles of M. javanica. The effect of P. harmala is due to its possession of a high content of β-carboline alkaloids, which warrant further experimentation. Bioproducts from P. harmala should be exploited through formulations for management of the root knot nematode.

In this study, the efficiency of Aspergillus flavus (A. flavus) was studied in the treatment of three landfill leachate types, namely young, intermediate and old ( YL, IL and OL ) in terms of removal of organic and nitrogen matter, as well as genotoxicity. The organic fraction of landfill leachate was measured by biological oxygen demand (BOD5) and chemical oxygen demand (COD), and the nitrogen fraction was measured by ammonium (NH 4 + ). The genotoxicity was evaluated using the Vicia faba root-micronucleus test. The analysis of the three leachates revealed high values of COD ( 9517.4-19 523.33 mg/L), BOD5 ( 1756.8-11 600 mg/L), NH 4 + ( 5931.25-3112.68 mg/L) and total chromium ( C r T: 0.06-3.78 mg/L). The three leachates also showed genotoxic effect on Vicia faba cells at a 1% leachate concentration. The treatment of leachates with A. flavus led to considerable reduction of pollutant load, and it was found to be more effective in reducing COD (30.12 %) and BOD 5 (71.29%) in YL and NH 4 + (98.21%) in IL after 30 days of treatment. A decrease in Micronucleus frequency (48.57-52.32 ‰) was observed in Vicia faba cells exposed to treated OL and IL compared to raw samples, while no such reduction was observed in the treated YL. The treatment of leachate with A. flavus showed more efficiency in genotoxicity removal for OL and IL. However, treated YL still possesses genotoxic character, even if it recorded the highest COD removal rate. Thus, the evaluation of leachate bioremediation on genotoxicity removal effectiveness should be included in landfill leachate risk assessment studies in order to ensure safe levels for its disposal in the environment.

The present study investigates the ability of Aspergillus flavus (A. flavus) for organic and nitrogen matter removal from landfill leachate. Experiments were carried out with different types of leachate, (Young (YL), Intermediate (IL) and Old (OL)) used at different concentrations of the leachate up to 100%. The organic fraction of landfill leachate was measured by biological oxygen demand (BOD5) and chemical oxygen demand (COD) then it was qualitatively assessed using three dimensional excitation emission matrix (3D-EEM). The nitrogen fraction was measured by ammonium (NH4+) and nitrate (NO3-). The experiments revealed that, BOD5, COD and NH4+ removal rates after 4 weeks of treatment in flasks were within the ranges of 47.90-81.63%, 12.91-48.50% and 70.84-98.81%, respectively and that affected the reduction of the phytotoxicity in a positive way. A. flavus with 25% concentration of YL recorded the best results in reducing COD and BOD5 with maximum removal rates of around 48.50% and 81.63%, respectively. However, the highest NH4+ removal rate of 98.81% was found in 25% concentration of OL. The 3D-EEM results showed that the intensities of the fluorescent peaks for the three treated leachates have decreased sharply after treatment. This was confirmed by the increase of the organic matter complexity index for different treatments (from 0.55 to 0.87). Therefore, A. flavus may be potentially useful in the treatment of landfill leachate at a concentration of less than or equal to 50% as it was able to remove organic and nitrogen compounds, particularly in the treatment of YL leachate at a concentration of 25%.