Sorption of lead ions from aqueous solution onto Enterococcus faecium biomass.

This study reports kinetics and equilibrium of lead sorption onto the biomass of Enterococcus faecium. E. faecium is a lactic acid bacterium and was isolated from meat. Batch experiments were carried out to analyze the effects of the initial lead concentration, initial pH of the medium, agitation time and temperature on the biosorption. The lead sorption was found to increase with the increase in the solution pH, reaching a plateau value beyond pH 5, and the most favorable pH for removal was determined as 5.0. The highest lead uptake capacity of the biomass was obtained at the initial lead concentration of 300 mg L(-1). The Langmuir and Freundlich adsorption models were applied to determine the biosorption isotherm, and the equilibrium data correlated well with the Langmuir model. The pseudo-second-order kinetic model was more suitable to fit the experimental data. The results were promising that the biomass of this lactic acid bacterium can be successfully used as a convenient adsorbent for lead removal from aqueous solutions.

Microbiota of Endodontically Infected Primary and Permanent Teeth.

Purpose: Differences in the endodontic microbiome of permanent and primary teeth during the mixed dentition period are still unknown. The purpose of this study was to examine bacterial diversity in endodontically infected primary and permanent teeth using 16S rRNA gene sequencing and the QIIME 2 (Quantitative Insights Into Microbial Ecology 2) bioinformatics pipeline. Methods: Microbial samples from endodontically infected primary (n equals 15) and permanent (n equals 15) maxillary or mandibular molar teeth were subjected to next-generation sequencing analysis based on examination of the hypervariable V3 to V4 region of the 16S rRNA gene. Statistical analysis was performed using R software. Results: Of 1,664,926 reads and 2,237 operational taxonomic units, 14 phyla, 89 families, and 236 genera were identified. Firmicutes were the most commonly detected phyla in both endodontically infected primary and permanent root canals. Bacteroides and Proteobacteria were more common in primary teeth, whereas Actinobacteria and Verrucomicrobia were more common in permanent teeth. The overall canal microbiota composition was similar in endodontically infected primary and permanent teeth (P=0.338). Conclusions: This study provides a comprehensive assessment of microbiota composition in endodontically infected primary and permanent teeth and gives a deeper insight into the origin of the root canal infections.