Widespread release of cyanide from industrial activities represents a significant environmental challenge due to its acute toxicity and adverse effects on biological systems. In response to this concern, this study focused on the production of rhodanese from Kocuria rhizophila under submerged fermentation conditions and the assessment of its relevance for cyanide detoxification applications. A soil-derived Gram-positive bacterium was isolated and identified as Kocuria rhizophila based on morphological traits, biochemical profile-based VITEK 2 analysis, and 16S rRNA gene sequencing. Preliminary screening confirmed rhodanese production with an activity of 0.968 RU/mL. Under cyanide-induced submerged fermentation, enzyme production followed a growth-associated pattern and reached maximal activity at 40 h under optimized conditions (35 °C, pH 8.0). Partial purification using sequential precipitation and chromatographic steps enhanced enzyme purity, and SDS–PAGE analysis of the final fraction revealed protein bands at approximately 40, 140, and 260 kDa. Biochemical characterization showed Km values of 33.9 mM for KCN and 19.7 mM for sodium thiosulfate, with a Vmax of ~5.6 µmol min⁻¹ mL⁻¹ for KCN and optimal activity at pH 7–8 and 35 °C. Functional assays demonstrated efficient cyanide detoxification, achieving >85% conversion of KCN, ~92% of NaCN, and 65–77% of Ca (CN)₂ within 60 min in vitro. Collectively, these findings demonstrate that Kocuria rhizophila represents a promising microbial source of rhodanese with efficient cyanide-detoxifying activity, highlighting its potential for biotechnological and environmental remediation applications.

Drought stress poses a critical threat to global maize (Zea mays L.) production, impairing physiological and biochemical functions and significantly reducing crop yield. This study evaluated the potential of foliar-applied nano-fertilizers – zinc (Zn), iron (Fe), and silica (Si) nanoparticles – in mitigating drought-induced damage in maize across two consecutive growing seasons (2023–2024). A factorial experiment was conducted under controlled greenhouse conditions with 12 treatment combinations comprising three drought levels (non-drought, moderate, severe) and four nano-fertilizer regimes (control, Zn, Fe, Si). Comprehensive physiological and biochemical parameters were measured, including photosynthetic pigments, antioxidant enzyme activities, oxidative stress markers, proline, protein content, and gas exchange traits (photosynthesis and transpiration rates). Results showed that drought stress significantly reduced chlorophyll and carotenoid content, impaired photosynthesis, and elevated oxidative damage. However, nano-fertilizer treatments – particularly nano-Fe and nano-Zn – enhanced chlorophyll retention, increased antioxidant enzyme activities and seed yield, and lowered malondialdehyde (MDA), electrolyte leakage (EL), and hydrogen peroxide (H2O2) accumulation. Nano-Si notably improved transpiration and proline accumulation, aiding osmotic adjustment. Among treatments, moderate drought combined with nano-Fe (MDNFe) and Zn (MDNZn) consistently outperformed controls, demonstrating improved pigment stability, enzymatic protection, and physiological performance. Correlation analysis revealed strong positive associations between chlorophyll content and photosynthetic traits (r > 0.98), and between antioxidant activity and stress mitigation indicators. This study provides mechanistic insights into the nano-enabled resilience of maize under drought stress and highlights the synergistic role of micronutrient nanoparticles in enhancing plant antioxidant and osmoprotective responses. The findings advocate for the integration of nano-Zn, nano-Fe, and nano-Si into sustainable drought management practices to promote climate-resilient maize cultivation.

Nano-silica (Si) and nano-zinc (Zn) are increasingly used to mitigate drought stress, yet their combined effects on both plant physiology and essential oil