The congo red dye, present in textile effluents, is extremely stable towards light, heat, microorganisms and poses serious toxicity issues due to presence of carcinogenic aromatic amines. Magnesium oxide nanoparticles (MgO-NPs) are effective in degrading azo dyes, due to their distinctive physicochemical and catalytic properties, antibacterial effects, and relatively low toxicity. In this study, production of MgO-NPs via a native bacterial isolate Shigella sp. SNT22, their entrapment into Ca-alginate beads, and the determination of their photocatalysis potential for congo red degradation and treating textile wastewater is documented. The UV–VIS spectroscopy confirmed the MgO-NPs by a signature peak at 270 nm. As revealed by FTIR analysis, different functional groups stabilized the MgO-NPs, and the average calculated size of MgO-NPs was 46.89–55.08 nm. The X-ray diffraction pattern revealed the synthesis of pure and crystalline MgO-NPs. The MgO-NPs showed minimal cytotoxic effects to retinal pigment epithelial cell line, maintaining over 90% cell survival even at high concentrations (up to 100 ppm). In an immobilized form with Ca-alginate, the MgO-NPs were able to remove 89.33% CR from aqueous dye solution at 2 mg/mL concentration of nanoparticles after 5h of solar exposure. Moreover, textile effluents treated with MgO-NPs beads reduced pH (24%), electrical conductivity (EC) 38%, total dissolved solids (TDS) 64%, and chemical oxygen demand (COD) 72% in effluents. Overall, the study revealed an ecofriendly and scalable approach of applying MgO-NPs in entrapped form for wastewater treatment to avoid NPs direct environmental release.

Pulses are essential crops but face challenges from abiotic and biotic stress, especially heavy metal stress, which significantly affects chickpea growth. The focus of the current research was to evaluate the effect of co-applied ZnO-NPs and Ni-resistant plant growth-promoting rhizobacteria (PGPR) for growth and development of chickpea while minimizing nickel stress. A pot experiment was conducted to check the phytotoxicity threshold of ZnO-NPs, with foliar application of ZnO-NPs at concentrations of 0, 25, 50, 75, and 100 mgL⁻¹, along with PGPR strains (Shewanella sp. and Bacillus flexus). The individual and combined effect of ZnO-NPs (100 mgL⁻¹) and PGPR (Shewanella sp.) was also checked against Ni stress in chickpea and an average reduction in Ni toxicity of up to 48.6% was detected, where antioxidants, photosynthetic, and growth parameters were increased in co-application of both the bio stimulants, while oxidants decreased significantly. The significant improvement was noticed by photosynthetic parameters such as chlorophyll a and b upto 35.8% and 38.09%. Root and shoot length were enhanced by 28.7% and 34.9% in the combined application in comparison to the control, respectively. It is concluded that biosynthesized ZnO-NPs and Shewanella sp. PGPR together could be optimal to treat Ni stress and to improve chickpea yield.

The Korang River is a significant water source, supporting varied aquatic ecosystems, and is vital for regional water supply and ecological balance. This study was conducted to assess the Korang River heavy metals (HMs) contamination, cancer and non-cancer risks, through health risk indices, and source apportionment. Eighty-three (83) surface water samples were analyzed via Atomic Absorption Spectrometer (AAS) for HMs concentration. The study sites are classified into three contamination zones through cluster analysis (CA) and self-organizing maps (SOM). In zone I, Ni (0.054 mg/L) exceeded the WHO permissible limit and is slightly contaminated. Zone II showed more contamination, with Fe (14.3 mg/L), Ni (0.136 mg/L), Cr (0.14 mg/L), and Cd (0.0123 mg/L) exceeding WHO permissible limits. Zone III was moderately contaminated, as Fe (4.98 mg/L) and Ni (0.063 mg/L) concentrations exceeded the permissible limits, and are less contaminated. The Hazard Index (HI) and Cancer Risks (CR) of Cr, Cd, and Ni were above the threshold level, showing both cancer and non-cancer health risks in adults and children. Through the Positive Matrix Factorization (PMF) model, four major sources of HMs were identified. These sources are industrial effluents (30.2 %), household waste (25.2 %), traffic emissions (24.4 %), and geological weathering (20.2 %). These findings highlight the urgent need for effective management of industrial effluents, traffic emissions, and household waste through solid measures. Although this study is site-specific, the approach can be applied in other areas having similar industrial and urban setup for better contamination management.

Soil microbes play an important role in nutrient cycling, and their richness and diversity are greatly influenced by cropping patterns and soil management systems. However, the effect of different cropping systems of rice on soil microorganism is still obscure. Therefore, this field experiment was conducted to study the effects of various paddy-upland multiple cropping rotation patterns on soil microbial community structure and diversity. The experiment comprised different treatments, Chinese milk vetch (Astragalus sinicus L.)-double cropping rice (CRR, CK), rape-early rice-late rice (RRR), potato (Solanum tuberosum L.)-early rice-late rice (PRR), Chinese milk vetch-early rice-sweet potato (Ipomoea batatas (L.) Lam.) late soybean (Glycine max (L.) Merr.) (CRI), and rape (Brassica napus L.)-early rice-sweet potato late soybean (RRI). The results showed that rapeseed and Chinese milk vetch in winter was conducive to increasing bacterial community richness and diversity. For each cropping pattern, the top three dominant phyla in paddy fields were Proteobacteria, Chloroflexi and Actinobacteria in terms of relative abundance. The community structure of soil bacteria showed more significant internal variability in CRI and RRI treatments and less internal variability in others treatments. Redundancy analysis of soil bacterial community structure and soil chemical properties revealed that soil bacterial community structure changes were primarily influenced by organic C, its fractions, and N content. In conclusion, Chinese milk vetch-early rice-sweet potato and late soybean cropping patterns may be considered for sustainable early and late rice production due to their beneficial impacts on soil bacterial abundance, diversity, and soil properties.

Purpose

Greenhouse gases (GHGs) are major reasons for climate change. The intensity of GHGs is continuously increasing in agricultural soils due to intensive practices. Biochar (BC) is an effective measure to mitigate GHGs and improve ecosystem services. However, the efficiency of BC in mitigating nitrous oxide (N₂O) emissions remains debatable. In recent years, BC, when combined with other amendments, has shown promising results in mitigating N₂O emissions. Recently, seaweed-based fertilizers (SBF) have shown promising results in improving crop productivity; however, their role in reducing GHG emissions is still unclear.

Method

This study investigated the impact of BC, SBF, and co-application of BC and SBF on N₂O emissions, soil rejuvenation, canonical ammonia oxidizers, and comammox, bacterial abundance, and rice growth and yield. The study contained different treatments: control, BC (2%), SBF (2%), and BC (1%) + SBF (1%).

Results

The co-application of BC + SBF increased soil pH (> 20%), triggered the transformation of soil nitrogen dynamics, increased soil carbon (92.74%), nosZ genes abundance (107%) and decreased ammonia-oxidizing archaea (AOA) (27%), and ammonia-oxidizing bacteria (AOB) (45%) abundance leading to a significant decrease in N₂O emissions (63.15%). The integrative application of BC and SBF also significantly increased Acidobacteriota, Bacterioidetes, Chloroflexi, Proteobacteria, and Nitrospirae, contributing to a significant decrease in N₂O emissions. Integrative BC and SBF also enhanced rice productivity and quality, which was linked with improved soil nutrient availability, carbon sequestration, and soil enzyme activities.

Conclusion

In conclusion, the BC and SBF blend could be a promising amendment to mitigate N₂O emissions and improve soil fertility, microbial activities, and rice productivity.

This research examines the influence of exogenous indole-3-acetic acid (IAA) on growth parameters and cadmium stress resistance in Sorghum bicolor (L. Moench). The plants were grown in pots, each filled with 4.5 kg of sand. After 21 days, root treatment with indole-3-acetic acid (IAA) was applied using five concentrations (0, 50, 100, 150, and 200 µM) under three cadmium (Cd) levels (0, 40, and 80 ppm). Applied Cadmium stress significantly reduced plant growth, with reductions in root length (12.73–15.88%), shoot length (17.60–19.25%), and plant height (10.62–14.88%). All growth parameters were improved with the application of 200 µM IAA, increasing root length (20.25–28.25%), shoot length (35.68–45.68%), and plant height (20.37%). The highest level of cadmium stress (80 ppm) was the most detrimental, while the 200 µM IAA treatment produced the most favorable results. Under cadmium stress, IAA application reduced the uptake of Na⁺, K⁺, and Ca²⁺ ions by 7.69–9.52%, 3.70–7.31%, and 6.66–7.69%, respectively, as well as Cd²⁺ by 2.50–5.26%. Despite these reductions, IAA application significantly enhanced antioxidant activities, including catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD). At 200 µM IAA, antioxidant enzyme activities were increased by 4.65% (SOD), 8.82% (POD), 10.06% (CAT), and 17.9% ascorbate peroxidase (APX). The treatment also boosted chlorophyll content (17.46–22.85%), while reducing oxidative stress markers such as H₂O₂ (29.4–40.8%) and malondialdehyde (38.9–42.1%). These findings suggest that IAA effectively mitigates cadmium-induced stress by improving growth parameters and physiological responses. Future research should explore the molecular mechanisms underlying IAA-mediated cadmium stress alleviation.

This study explored the valorization of two carbohydrate rich food wastes, a sugary (spoiled dates, SD) and a starchy (wasted rice, WR) one, for the biotechnological production of α-amylase, biohydrogen (bioH₂), and methane (CH₄). Initially, the bioH₂ and CH₄ production potentials of raw SD and WR were assessed without any pretreatment, via dark fermentation and anaerobic digestion, respectively, to evaluate the need of sacharification of the wastes for achieving efficient yields. For the production of amylolytic enzymes the bacterium Bacillus amyloliquefaciens was used. Aerobic experiments with synthetic media were initially performed to evaluate the effect of carbon and nitrogen sources on microbial growth, substrate uptake and stimulation of α-amylase production. Subsequently a mixture of the SD and WR, supplemented with peptone, was used as a substrate for α-amylase production, achieving a maximum enzymatic activity of 35.7 ± 1.1 AU mL⁻¹. The impact of enzymatic and acid saccharification on biofuel production was then evaluated using commercial α-amylases, crude α-amylase produced in situ by B. amyloliquefaciens, and HCl. Commercial enzymes maximized bioH₂ yields, while crude α-amylase also enhanced production considerably. HCl pretreatment improved WR conversion but reduced bioH₂ yields from SD. Saccharification showed only a limited effect on CH₄ production, with no statistically significant improvements over untreated WR. Overall, SD and WR show strong potential as zero-cost feedstocks for α-amylase and gaseous biofuel production, supporting circular economy principles. Valorization of these carbohydrate-rich wastes could reduce feedstock costs and provide a sustainable approach to enzyme and bioenergy generation.

This study examines the potential inhibitory effects
of extracts of seven Mediterranean macroalgae on the
germination success of two harmful dinoflagellate cysts,
Gymnodinium catenatum and Ostreopsis cf. ovata. The
results revealed that aqueous and methanolic extracts
of these macroalgae showed varying inhibitory effects
on the viability of the cyst germlings, preventing them
from dividing and producing motile vegetative cells.
Among macroalgae, three Cystoseira species (C. compressa,
C. barbata, and C. crinita) exhibited the strongest inhibitory
effects on the germination success of the two cyst types.
The methanolic extracts of these species showed higher
inhibitory effects on O. cf. ovata cysts (% inhibition =
88%–100%) than G. catenatum cysts (83%–95%). Based on
the median inhibitory concentration (IC50), the methanolic
extracts of these macroalgae have exhibited stronger
inhibitory effects on germling viability (IC50 = 0.05–1.5 mg
extract g−1 sediment) than aqueous extracts (IC50 =
0.9–590 mg extract g−1 sediment). The study suggests that
macroalgal materials, specifically Cystoseira species, would
be a promising approach to retard the germination success
of dinoflagellate cysts in constricted coastal areas, hence
limiting the recurrence of harmful algal blooms in the
water column