Precise evaluation of batch adsorption kinetics of plant total polyphenols based on a flow-injection online spectrophotometric method.

Efficient evaluation of adsorption kinetics of plant total polyphenols is essential for the design of adsorption separation of bioactive compounds. The conventional method uses manual sampling with poor reproducibility. Here, we developed a new method for on-line determination of total polyphenol content (TPC) in plant extracts by applying the Folin-Ciocalteu method in flow-injection analysis (FIA). The FIA parameters were optimized and a standard curve with excellent linearity was established. Precise determination of TPC with a satisfactory sample throughput of 20 h-1 was achieved for the adsorption kinetic study. The pseudo-second-order kinetic model was found to better describe the kinetic parameters of the batch adsorption/desorption process. The developed method proved to be accurate compared with the conventional method. The FIA method holds significant promise for studying and monitoring adsorption processes, due to its automatic on-line nature, low consumption of reagents and samples, and the ability to generate large quantities of highly accurate adsorption data.

Degradation of pendimethalin by the yeast YC2 and determination of its two main metabolites.

In this study, we isolated a yeast strain, YC2, by enrichment culture from pendimethalin-contaminated soil. The analysis of its phenotypic features and 26S rRNA sequence confirmed that the strain YC2 is Clavispora lusitaniae. According to the kinetics of pendimethalin degradation, YC2 could degrade 74% of 200 mg L-1 pendimethalin in CMB liquid culture over 8 days. LC-MS/MS was used to identify the metabolites of pendimethalin after degradation. This study confirmed that its metabolites consist of 1,2-dimethyl-3,5-dinitro-4-N(buta-1,3-dien-2-yl)-dinitrobenzenamine-N-oxide and 1,2-dimethyl-3,5-dinitro-4-N(prop-1-en-2-yl)-dinitrobenzenamine-N-oxide, which were broken down by a series of enzymatic reactions to produce CO2 and H2O. Thus, the study herein sheds light on the role of yeast in the degradation of pendimethalin.