Aflatoxin contamination of food products is recognised as a major food safety concern throughout the world because of its carcinogenic, mutagenic, and immunosuppressive effects on human health. Of the various types of aflatoxins, aflatoxin B1 (AFB1) is the ubiquitous and most threatening foodborne mycotoxin to humans. A wide range of detoxification methods is used to reduce the toxic effects of AFB1. In the present work, the ability of probiotics isolated from yoghurt (produced by bacterial fermentation of milk), “laban” (fermented milk beverage), and “idli” batter (fermented rice and black gram) in the detoxification of AFB1 was investigated under laboratory conditions. Among the four isolates from fermented foods evaluated, the isolate YGT1 from yoghurt showed the maximum (83.8%) degradation of AFB1 in Luria-Bertani (LB) liquid medium after 48 h of incubation at 30°C. The degradation of AFB1 by the probiotic isolate was further confirmed by liquid chromatography/mass spectrometry analysis. On the basis of 16S rRNA gene sequence analysis, the bacterial isolate YGT1 was identified as Bacillus subtilis. The culture supernatant and heat-treated culture supernatant (boiled for 30 min) of B. subtilis YGT1 also exhibited degradation of AFB1, thus suggesting the involvement of thermostable bioactive compound(s) in the degradation of AFB1. These results suggested that B. subtilis YGT1 isolated from yoghurt may be a promising candidate for exploitation in food and feed industries for the removal of AFB1.

This paper presents an in-depth characterization of a raw industrial sludge (IS-R) and its KOH-activated biochar pyrolyzed at 750 °C (IS-KOH-B) followed by their application to remove a cationic dye from aqueous solution. Materials characterization shows that compared to the IS-R, the IS-KOH-B has improved structural, textural, and surface chemical properties. In particular, the IS-KOH-B’s BET surface area and total pore volume are about 78 and 6 times higher than those found for the IS-R, respectively. The activated biochar efficiently retained the cationic dye under wide experimental conditions. Indeed, for an initial dye concentration of 50 mg L−1, removal yields were assessed to be more than 92.5%, 93.5%, and 97.8% for a large pH range (4–10), in the presence of high contents of competing cations (3000 mg L−1 of Ca2+, Mg2+, Na+, and K+), and a low used adsorbent dose (1 g L−1), respectively. The Langmuir’s adsorption capacities were 48.5 and 65.9 mg g−1 for of IS-R and IS-KOH-B, respectively, which are higher than those reported for various adsorbents in the literature. The dye removal was found to be monolayer, spontaneous, and endothermic for both the adsorbents. Moreover, this removal process seems to be controlled by chemical reactions for IS-KOH-B whereas by both physico–chemical reactions for IS-R. This study demonstrates that the raw industrial sludge and especially its KOH-activated derived biochar could be considered as promising adsorbents for the removal of dyes from aqueous solutions.

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In this study, endophytic and rhizospheric bacteria were isolated from Moringa olifera and M. perigreina from Oman, and their in vitro antagonistic activity against Pythium aphanidermatum was tested using a dual culture assay. The promising strains were tested further for their compatibility and potential for plant growth promotion, biofilm formation, antifungal volatile organic compound (VOC) production, and the biological control of P. aphanidermatum damping-off of cabbage (Brassica oleracea L.) under greenhouse conditions. A total of 12 endophytic and 27 rhizospheric bacteria were isolated from Moringa spp. Among them, Bacillus pumilus MPE1 showed the maximum antagonistic activity against P. aphanidermatum in the dual culture assay, followed by Paenibacillus glucanolyticus MPE3 and Pseudomonas indica MOR3 and MOR8. These bacterial isolates induced abundant morphological abnormalities in the hyphae of P. aphanidermatum, as observed via scanning electron microscopy. The in vitro cross-streak assay showed that these bacterial isolates were compatible among themselves, except for P. indica MOR8 × P. glucanolyticus MPE3. These antagonists released VOCs that restricted the growth of P. aphanidermatum in an in vitro assay. These antagonistic bacteria released 2,4-dimethylheptane and 4-methyloctane as the predominant volatile compounds. Of the four antagonistic bacterial strains, P. indica MOR8 was capable of forming biofilm, which is considered a trait that improves the efficacy of rhizosphere inoculants. The results of the greenhouse experiments showed that the soil treatment with B. pumilus MPE1 showed the highest reduction (59%) in the incidence of P. aphanidermatum damping-off in cabbage, evidencing its potential as a biological control agent for the management of this disease. Further research is needed to characterize the antifungal traits and activities of B. pumilus MPE1 and to assert its potential use against other soil-borne plant pathogens.

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