An insight on the plausible biological and non-biological detoxification of heavy metals in tannery waste: A comprehensive review.

A key challenge for the tannery industries is the volume of tannery waste water (TWW) generated during the processing of leather, releasing various forms of toxic heavy metals resulting in uncontrolled discharge of tannery waste (TW) into the environment leading to pollution. The pollutants in TW includes heavy metals such as chromium (Cr), cadmium (Cd), lead (Pb) etc, when discharged above the permissible limit causes ill effects on humans. Therefore, several researchers have reported the application of biological and non-biological methods for the removal of pollutants in TW. This review provides insights on the global scenario of tannery industries and the harmful effects of heavy metal generated by tannery industry on micro and macroorganisms of the various ecological niches. It also provides information on the process, advantages and disadvantages of non-biological methods such as electrochemical oxidation, advanced oxidation processes, photon assisted catalytic remediation, adsorption and membrane technology. The various biological methods emphasised includes strategies such as constructed wetland, vermitechnology, phytoremediation, bioaugmentation, quorum sensing and biofilm in the remediation of heavy metals from tannery wastewater (TWW) with special emphasize on chromium.

Probiotics in Counteracting the Role of Neutrophils in Cancer Metastasis.

Neutrophils are known for their role geared towards pathogen clearance by different mechanisms that they initiate, primarily by the release of neutrophil extracellular traps (NETs). However, their immune-surveillance capacity accompanied with plasticity in existing as interchangeable subsets, discovered recently, has revealed their property to contribute to complex cancer pathologies including tumor initiation, growth, angiogenesis and metastasis. Although there is a growing body of evidence suggesting a critical balance between the protumoral and antitumoral neutrophil phenotypes, an in-depth signaling pathway analysis would aid in determination of anticipatory, diagnostic and therapeutic targets. This review presents a comprehensive overview of the potential pathways involved in neutrophil-triggered cancer metastasis and introduces the influence of the microbial load and avenues for probiotic intervention.

Biodegradation and biosorption of Reactive Red 120 dye by immobilized Pseudomonas guariconensis: Kinetic and toxicity study.

Reactive dyes are pernicious pollutants in textile effluent, which are to be treated passably before discharging into the environment. In the present study, a potential dye degrading bacterial strain Pseudomonas guariconensis was isolated from paddy rhizosphere and was characterized by 16S rRNA gene sequencing. The biodegradation ability of the strain was evaluated by time-based study with immobilized bacterial cells in calcium alginate biocarrier matrix and also with free cells. The results indicated that the strain exhibited maximum degradation of 91% when immobilized in the biocarrier matrix. The enzymatic study revealed the production of oxidoreductase enzymes. The degraded products were identified as 2-amino-3-phenylpropanoic acid and benzoquinone by gas chromatography-mass spectroscopy (GC-MS) analysis, and a degradative pathway was derived based on the enzymatic profile. A packed bed column was designed using P. guariconensis VITSAJ5 immobilized in calcium alginate beads as a biosorbent for the removal of Reactive Red 120. The immobilized bacterial cells exhibited 87% uptake of RR120, whereas the nonimmobilized bacterial cells exhibited a maximum uptake of 37%. The phytotoxicity analysis by seed germination assay revealed an enhanced plumule and radicle length, indicating the nontoxic byproducts after the treatment of Reactive Red 120 by VITSAJ5 compared to the untreated Reactive Red 120 solution. PRACTITIONER POINTS: Current study is the first report on Pseudomonas guariconensis capable of degrading reactive dyes (Reactive Red 120) It was observed that the degradation potential was maximum when cells were immobilized with Ca-Ag biocarrier matrix Breakdown metabolism of Reactive Red 120 was derived through pathway prediction Employing immobilized bacteria in a packed bed column found to possess a prominent biosorption ability on the matrix enhancing the degradation process Toxic reactive dye was converted into nontoxic compounds, evidenced by phytotoxicity studies.

Monitoring the stress resistance of Pennisetum purpureum in Pb (II) contaminated soil bioaugmented with Enterobacter cloacae as defence strategy.

Lead (Pb) is reported to have negative effects on the biogeochemical behaviour of the plant growth. In recent years, the significance of rhizoremediation of heavy metals has been of great focus aiding in the development rates of plants under stressed conditions. The present study evaluated the physio-biochemical response of Pennisetum purpureum to different concentrations of Pb (II) viz., 0, 50, 100 and 150 mg kg-1 in the form of lead (II) nitrate. The pre-characterized PGPR strain, Enterobacter cloacae - KU598849 was used to augment the plants. After Pb exposure for 45 d, parameters such as plant growth, lead accumulation, H2O2 content, MDA content, protein, proline content and antioxidant enzymatic activities were quantified. Results illustrated that increasing Pb concentration reduced the early growth, metal accumulation, protein content and affected physio-biochemical changes by causing oxidative damage in plants. Upon augmentation of the bacterial inoculum, the plants significantly resisted the toxic effects of Pb. Increased Pb bioaccumulation pattern was recorded in roots than shoots, were highest uptake was found to be 72 mg kg-1 dry weight when exposed to 150 mg kg-1 Pb concentration. Lead supplementation increased the activities of malonylaldehyde (MDA), superoxide dismutase (SOD), peroxidase (POX), ascorbate peroxidase (APX) and catalase (CAT) in P. purpureum. Bacterial bioaugmentation resulted in the reduction of the oxidative stress aided with reduced antioxidant enzyme activities indicating the minimization of the damages under stress.

Enhanced bioremoval of lead by earthworm-Lumbricus terrestris co-cultivated with bacteria-Klebsiella variicola.

Lead is a toxic heavy metal having devastating effects on the environment. The current study was focussed on bioremoval of lead using earthworm and lead resistant bacteria. Earthworms were subjected to various concentrations of lead in the soil bioaugmented with lead resistant bacteria (VITMVCJ1) to enhance the uptake of lead from the contaminated soil. Significant increase was observed in the length and body weight of the earthworms supplemented with lead resistant bacteria. Similarly, there was a substantial increase in the locomotion rate of the earthworms treated with lead resistant bacteria in comparison with the control. The gut micro flora of bacterial treated earthworms had increased number of bacterial cells than the untreated earthworms. The histopathological studies revealed the toxic effects of lead on the gut of earthworms indicating severe damage in lead resistant bacteria untreated worms, whereas the cells were intact in lead resistant bacteria treated worms. COMET assay showed increased DNA damage with higher tail DNA percent in the untreated earthworms. Further, the colonisation of the bacteria supplemented, onto the gut region of earthworms was observed by scanning electron microscopy. Atomic absorption spectrophotometry indicated a fair 50% uptake of lead within the biomass of earthworm treated with lead resistant bacteria.

Bioremoval of lead using Pennisetum purpureum augmented with Enterobacter cloacae-VITPASJ1: A pot culture approach.

Lead is a toxic heavy metal discharged into the ecosystem from various industries. Biological remediation strategies have been effective in the bioremoval of lead. In our current study, a phytobacterial system using Pennisetum purpureum along with lead-resistant bacterium (LRB) was employed for the uptake of lead. The LRB was obtained from lead-contaminated sites. The isolate VITPASJ1 was found to be highly tolerant to lead and was identified as an effective plant growth-promoting bacterium. The 16S rRNA sequencing revealed VITPASJ1 to be the closest neighbour of Enterobacter cloacae. The lead-resistant gene pbrA in the plant and the bacterium were amplified using a specific primer. The uptake of lead was studied by phytoremediation and rhizoremediation set-ups where the soil was supplemented with various concentrations of lead (50, 100, 150 mg/kg). The plants were uprooted at regular intervals, and the translocation of lead into the plant was determined by atomic absorption spectroscopy. The root length, shoot height and chlorophyll content were found to be higher in the rhizoremediation set-up when compared to the phytoremediation set-up. The scanning electron microscopic micrographs gave a clear picture of increased tissue damage in the root and shoot of the phytoremediation set-up as compared to the rhizoremediation set-up with LRB.

Comparison of soil bacterial communities of Pinus patula of Nilgiris, western ghats with other biogeographically distant pine forest clone libraries.

The bacterial community structure of the rhizosphere and non-rhizosphere soil of Pinus patula, found in the Nilgiris region of Western Ghats, was studied by constructing 16S rRNA gene clone libraries. In the rhizosphere and non-rhizosphere soil clone libraries constructed, 13 and 15 bacterial phyla were identified, respectively. The clone libraries showed the predominance of members of culturally underrepresented phyla like Acidobacteria and Verrucomicrobia. The Alphaproteobacteria and Acidobacteria clones were predominant in rhizosphere and non-rhizosphere soil samples, respectively. In rhizosphere, amongst Alphaproteobacteria members, Bradyrhizobium formed the significant proportion, whereas in non-rhizosphere, members of subdivision-6 of phylum Acidobacteria were abundant. The diversity analysis of P. patula soil libraries showed that the phylotypes (16S rRNA gene similarity cutoff, ≥97 %) of Acidobacteria and Bacteroidetes were relatively predominant and diverse followed by Alphaproteobacteria and Verrucomicrobia. The diversity indices estimated higher richness and abundance of bacteria in P. patula soil clone libraries than the pine forest clone libraries retrieved from previous studies. The tools like principal co-ordinate analysis and Jackknife cluster analysis, which were under UniFrac analysis indicated that variations in soil bacterial communities were attributed to their respective geographical locations due to the phylogenetic divergence amongst the clone libraries. Overall, the P. patula rhizosphere and non-rhizosphere clone libraries were found significantly unique in composition, evenly distributed and highly rich in phylotypes, amongst the biogeographically distant clone libraries. It was finally hypothesised that the phylogenetic divergence amongst the bacterial phylotypes and natural selection plays a pivotal role in the variations of bacterial communities across the geographical distance.