In this study, we explored the adsorption potential of biochar derived from palm kernel shell (BC-PKS) as an affordable adsorbent for the removal of crystal violet from wastewater. Kinetics, equilibrium, and thermodynamics studies were carried out to evaluate the adsorption of crystal violet onto BC-PKS. The kinetics adsorption process followed the pseudo-second-order model, indicating that the rate of adsorption is principally controlled by chemisorption. The adsorption equilibrium data were better fitted by the Langmuir isotherm model with a determination coefficient of 0.954 and a maximum adsorption of 24.45 mg/g. Thermodynamics studies found the adsorption of crystal violet by BC-PKS to be endothermic with increasing randomness at the BC-PKS/crystal violet interface. The percentage removal and adsorption capacity increased with the pH of the solution, as the negative charges on the biochar surface at high pH enhance the electrostatic attraction between crystal violet molecules and BC-PKS. Increasing the BC-PKS dosage from 0.1 to 1.0 g increased percent removal and decreased the adsorption capacity of crystal violet onto BC-PKS. Therefore, biochar from agricultural by-products, i.e., palm kernel shell, can be cost-effective adsorbents for the removal of crystal violet from textile wastewater.

Levels of curcuminoids and essential oil compositions from eighteen turmerics (Curcuma longa L.) grown in Jeju were analyzed. 0.5 g of turmeric samples was extracted with 20 mL of methanol for 7 h by shaking and was ultra-sonicated for 30 min. The extracts were analyzed by high-pressure liquid chromatography-diode array detector using Brownlee SPP C18 column (4.6 × 100 mm, 2.7 µm) after filtration. Curcumin (CUR), demethoxycurcumin (DEM), and bisdemethoxycurcumin (BIS) were monitored at the wavelength of 420 nm. Total curcuminoids in turmerics ranged from 53.9 ± 1.0 to 5396.0 ± 101.8 µg/g dry turmeric weight. In decreasing order, curcuminoids found were CUR (4669.7 µg/g) > DEM (565.3 µg/g) > BIS (160.9 µg/g). K145023 variety contains the highest amount of curcuminoids and variety number 10 contains the least amount. Essential oils were extracted with steam distillation method and analyzed with GC–MS. The major components of turmeric oil were α-zingiberene (27.70–36.75 %), aromatic-turmerone (19.54–32.24 %), β-sesquiphellandrene (13.14–18.23 %), α-turmerone (3.72–6.50 %), β-turmerone (2.86–5.60 %), and β-bisabolene (2.50–3.46 %).

Chlorophyll breakdown is a vital catabolic process of leaf senescence as it allows the recycling of nitrogen and other nutrients. In the present study, we isolated rice senescence-induced receptor-like kinase (OsSRLK), whose transcription was upregulated in senescing rice leaves. The detached leaves of ossrlk mutant (ossrlk) contained more green pigment than those of the wild type (WT) during dark-induced senescence (DIS). HPLC and immunoblot assay revealed that degradation of chlorophyll and photosystem II proteins was repressed in ossrlk during DIS. Furthermore, ultrastructural analysis revealed that ossrlk leaves maintained the chloroplast structure with intact grana stacks during dark incubation; however, the retained green color and preserved chloroplast structures of ossrlk did not enhance the photosynthetic competence during age-dependent senescence in autumn. In ossrlk, the panicles per plant was increased and the spikelets per panicle were reduced, resulting in similar grain productivity between WT and ossrlk. By transcriptome analysis using RNA sequencing, genes related to phytohormone, senescence, and chlorophyll biogenesis were significantly altered in ossrlk compared to those in WT during DIS. Collectively, our findings indicate that OsSRLK may degrade chlorophyll by participating in a phytohormone-mediated pathway.

In this study, a multi-residue analysis was developed for 32 compounds, including pesticides and metabolites, in five meat products using gas chromatography-tandem mass spectrometry (GC-MS/MS). The validation of the developed analytical method was also evaluated in accordance with Codex Alimentarius guidelines. Aminopropyl (NH₂), C₁₈, and florisil solid phase extraction (SPE) cartridges were used to evaluate and optimize the cleanup procedure of the tested samples prior to GC-MS/MS analysis. Based on the analytical performance, the C₁₈ SPE cartridge was deemed to be the most suitable among the examined SPE cartridges. The optimized method demonstrated that 29 out of 32 tested compounds acquired good linearity (R² ≥ 0.99), and 25 tested compounds displayed the method limit of quantification (MLOQ) ≤ 0.01 mg/kg. Out of the 32 tested compounds, only 21 compounds met the acceptable analytical criteria for the lard and tallow samples, compared to 27 compounds in the beef, pork, and chicken samples that falls within the acceptable standards for recovery (70–120%) and analytical precision (relative standard deviation RSD ≤ 20%). The average matrix effect was widely varied (20.1–64.8%) in the studied meat samples that were affected by either ion enhancement or suppression. In particular, in the lard sample, 13 compounds showed poor recovery and analytical precision due to ion suppression. Thus, the matrix effect (ME) was considered a critical factor during multi-residue pesticide analysis in different meat products. In conclusion, this developed analytical method can be used as a routine monitoring system for residual pesticide analysis in livestock products with acceptable analytical standards. Further meticulous analytical studies should be optimized and validated for multi-residue pesticide analysis in diversified meat products.