Cobalt (Co) is widely used in many industrial fields such as batteries and paints. Cobalt, a dangerous heavy metal, can be found in high concentrations in natural and human habitats. Although cobalt is an important micronutrient, it is toxic to living organisms when exposed to high amounts. Carob (Ceratonia siliqua L.) is a tree native to The Mediterranean region. Carob bean, which has high nutritional and economic value, is used against cardiovascular and gastrointestinal diseases. In addition, the antioxidant properties of carob are gaining importance in recent years. In this study, the protective effects of carob extract against the toxicity of cobalt on Allium cepa L. were investigated. For this purpose, 150 mg/L and 300 mg/L carob extract solutions and 5.5 mg/kg cobalt solutions were applied to A. cepa L. bulbs. Root emergence, weight gain, root elongation, and mitotic index (MI) decreased, while the frequency of chromosomal abnormalities (CAs) and micronucleus (MN) increased as a result of Co application. Furthermore, Co treatment triggered a noticeable rise in the activities of superoxide dismutase (SOD) and catalase (CAT) enzymes as well as the malondialdehyde (MDA) amount and the abnormalities in the meristematic cells. On the other hand, applications of carob extracts mitigated cobalt-induced damages in a dose-dependent manner in all parameters. Therefore, the current study showed that the strong preventive potential of carob extract against phytotoxicity and genotoxicity is caused by Co in a model plant. The protective effects of carob extract on Co-induced toxicity were demonstrated for the first time in terms of reducing genotoxicity and oxidative stress response.

Increasing knowledge of nitrate removal using denitrifying bioreactors has illustrated the usefulness of this management practice for treating discharge water from agricultural land uses. The objective of this study was to assess the viability of almond shell, chopped carob, olive bone, and citrus woodchip as carbon media for denitrification of brine with high nitrate load (EC ≈ 20 dS m⁻¹, NO₃⁻-N concentration ≈ 65–80 mg NO₃⁻-N L⁻¹) in bioreactors. To the authors’ knowledge, this is the first test of denitrifying brine using organic wastes as the carbon substrate, and the first use of these carbon media for that purpose. Nitrate removal efficiency and efficiency:cost ratio were considered. The results indicated that the best removal efficiency and cheapest cost were provided by citrus woodchip (3.02 ± 0.15 mg NO₃⁻-N m⁻³ d⁻¹) at a cost of ≈ 6€ m⁻³, followed by almond shell (1.54 ± 0.20 mg NO₃⁻-N m⁻³ d⁻¹) at a cost of ≈ 19€ m⁻³. Chopped carob and olive bone showed negligible nitrate removal in the brine; chopped carob generated acidic leachate with extremely high dissolved organic carbon, and olive bone resulted in a highly saline leachate. Of the four media tested, the results of this study indicated that citrus woodchip was the most suitable media for denitrification of the brine.