M.G.H. Zaidi

Nanobarium Titanate As Supplement To Accelerate Plastic Waste Biodegradation By Indigenous Bacterial Consortia

Plastic waste biodegradation studies have seen several developmental phases from the discovery of potential microbial cultures, inclusion of photo‐oxidizable additives into the polymer chain, to the creation of starch‐embedded biodegradable plastics. The present study deals with the supplementation of nanobarium titanate (NBT) in the minimal broth in order to alter the growth‐profiles of the Low‐density polyethylene (LDPE) degrading consortia. The pro‐bacterial influence of the nanoparticles could be seen by substantial changes such as shortening of the lag phase and elongation of the exponential as well as stationary growth phases, respectively, which eventually increase the biodegradation efficiency. In‐vitro biodegradation studies revealed better dissolution of LDPE in the presence of NBT as compared to control. Significant shifting in λ‐max values was observed in the treated samples through UV‐Vis spectroscopy, while Fourier transform infrared spectroscopy (FTIR) and simultaneous thermogravimetric‐dif...

Response of indigenously developed bacterial consortia in progressive degradation of polyvinyl chloride

Thermoplastic-based materials are recalcitrant in nature, which extensive use affect environmental health. Here, we attempt to compare the response of indigenously produced bacterial consortium-I and consortium-II in degrading polyvinyl chloride (PVC). These consortia were developed by using different combination of bacterial strains of Pseudomonas otitidis, Bacillus cereus, and Acanthopleurobacter pedis from waste disposal sites of Northern India after their identification via 16S rDNA sequencing. The progressive degradation of PVC by consortia was examined via scanning electron microscopy, atomic force microscopy, UV–vis, FT-IR spectra, gel permeation chromatography, and differential scanning calorimetry analysis at different incubations and time intervals. The consortium-II was superior over consortium-I in degrading the PVC. Further, the carbon source utilization analysis revealed that the extensive use of consortia has not any effect on functional diversity of native soil microbes.

Selection of potential bacterial strains to develop bacterial consortia for the remediation of e-waste and its in situ implications

The management of electronic waste (e-waste) becomes a global issue in this digital era. Existing conventional practices are harmful for dealing with the e-waste, therefore, indigenous soil bacteria were explored for e-waste treatment through enrichment culture approach followed by screening, identification and their bioformulation used for in situ investigation. Soil bacteria were enriched in the presence of e-waste after 30 days of incubation under standard laboratory conditions. This finding was established through λmax values that were higher in the case of soil enrichment than the control. The biodegradation of e-waste by the selected strains during enrichment and in situ experiment was confirmed by FTIR, TG-DTG-DTA and SEM analysis. The FTIR spectra evidently support that microbial communities present in the enriched soil has affected the C-chain and used as carbon source for their growth. This chemical structural degradation of e-waste was further substantiated by thermal and SEM analysis. Thermograms experimentally show that the decomposition of the treated samples achieved comparatively at very low temperature than the control sample, while SEM micrographs revealed the surface morphology with distinct disintegrations. These result authenticated the biodegradation process carried out by the soil bacteria. Furthermore, bacterial community analysis confirmed that the used strains were persisting in the experimental pits throughout the trial period. Thus, this study besides providing direct and standardized protocol for screening and selection of efficient e-waste utilizing bacteria is also demonstrating potential consortia which are ready to be used.

Comparative in situ PET biodegradation assay using indigenously developed consortia

A soil burial test was carried out to evaluate the biodegradation of polyethylene terephthalate under natural environment for a period of six months in presence of three different indigenously developed bacterial consortia. These consortia comprised of potential polymer-degrading bacterial cultures isolated from various waste disposal sites. The comparative biodegradation of PET samples in presence and absence of used consortia was monitored through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). FTIR analysis implies structural changes in biodegraded PET samples unlike the control. The biodegradation is further substantiated by SEM which manifested the development of fissures and a sign of significant erosions which were progressive with the incubation time. Moreover, the DSC showed lowering of melting temperature (Tm) and heat of fusion (ΔHf) of biodegraded film samples suggesting their increased brittleness.