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 biodegradation studies of polyhydroxybutyrate film composites.

Application of polyhydroxybutyrate (PHB) to plastic industry has expanded over the last decades due to its attracting features over petro-based plastic, and therefore, its waste accumulation in nature is inevitable. In the present study, a total of four bacterial strains, viz., MK3, PN12, PW1, and Lna3, were formulated into a consortium and subsequently used as biological tool for degradation of biopolymers. The consortium was tested through λ max shifts under in vitro conditions for utilization of PHB as sole carbon source. Talc-based bioformulations of consortium were used for the degradation of PHB film composites under in situ conditions. After 9 months of incubation, the recovered samples were monitored through Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), respectively. Analytical data, viz., changes in λ max shifts (212-219 nm), FT-IR spectra, and SEM micrographs, revealed the biodegradation potential of developed consortium against PHB film composites, i.e., higher degradation of copolymer films was found over blend films. The used consortium had enhanced the rate of natural degradation and can be further used as a natural tool to maintain and restore global environmental safety.