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Electronic waste is termed as e-waste and on recycling it produces environmental pollution. Among these e-waste pollutants, polychlorinated biphenyls (PCBs) are significantly important due to ubiquitous, organic in nature and serious health and environmental hazards. PCBs are used in different electrical equipment such as in transformers and capacitors for the purposes of exchange of heat and hydraulic fluids. Bioremediation is a reassuring technology for the elimination of the PCBs from the environment. In spite of their chemical stability, there are several microbes which can bio-transform or mineralize the PCBs aerobically or anaerobically. In this review paper, our objective was to summarize the information regarding PCB-degrading enzymes and microbes. The review suggested that the most proficient PCB degraders during anaerobic condition are Dehalobacter, Dehalococcoides, and Desulfitobacterium and in aerobic condition are Burkholderia, Achromobacter, Comamonas, Ralstonia, Pseudomonas, Bacillus, and Alcaligenes etc., showing the broadest substrate among bacterial strains. Enzymes found in soil such as dehydrogenases and fluorescein diacetate (FDA) esterases have the capability to breakdown PCBs. Biphenyl upper pathway involves four enzymes: dehydrogenase (bphB), multicomponent dioxygenase (bphA, E, F, and G), second dioxygenase (bphC), hydrolase, and (bphD). Biphenyl dioxygenase is considered as the foremost enzyme used for aerobic degradation of PCBs in metabolic pathway. It has been proved that several micro-organisms are responsible for the PCB metabolization. The review provides novel strategies for e-waste-contaminated soil management.

Anaerobic digestion is a sustainable approach to deal with wastes with beneficial production of sustainable energy. In the anaerobic digestion processes, an increase in ammonia concentration hinders the efficacy of biogas production. The current study focused on minimizing the ammonia effect by the addition of zeolite as an adsorbent in a fluidized bed anaerobic reactor using poultry slaughterhouse waste as the substrate. The effects of zeolite dosage were investigated at mesophilic and thermophilic temperatures. Biomethane potential, volatile solids reduction, chemical oxygen demand, total volatile fatty acids concentration, ammonia–nitrogen levels, and pH were monitored. The initial biomethane potential test revealed that poultry slaughterhouse waste produces methane for up to 610 ml/g volatile solids (intestinal residues) and 200 ml/g volatile solids (feathers) at mesophilic conditions, 675 ml/g volatile solids (intestinal residues) and 276 ml/g volatile solids (feathers) at thermophilic conditions. The amendment with zeolite had significantly reduced chemical oxygen demand for up to 57%. Volatile solids reduction increased from 13 to 19%. Ammonia–nitrogen concentrations also decreased (15.5 mg/l) due to the application of zeolite. Enhanced biogas production of 700 ml/g volatile solids was observed after 25 days. It can be concluded that the addition of zeolite can significantly enhance biogas production by reducing the ammonia concentration in anaerobic digesters.

Background Antimicrobial resistance (AMR) is an emerging threat to public health worldwide. A significant evidence has suggested that the knowledge and attitude trends among the community, pharmacists and physicians can play a critical role in managing the ever increasing threat of AMR. Methods A cross-sectional survey was performed using three specific self-administered questionnaires for community members, pharmacists/pharmacy owners and physicians on a randomly selected sample population of 473, 424 and 308 respectively. Bivariate and multivariate logistic regression and Pearson chi-square tests were performed during data analysis. Result A response rate of 81.2% (n = 385), 37.7% (n = 160) and 53.9% (n = 166) was achieved for general community, pharmacists/pharmacy owners and physicians respectively. More than half of the community participants (55.6%; n = 214) possess poor knowledge of AMR. Furthermore, knowledge and attitude of the community participants were also found to be significantly correlated (r2 = 0.02) with each other. In 90.6% (n = 145) of the pharmacies included in the survey, a qualified pharmacist was not present at the time of the operations. Only 36.9% physicians (n = 60) knew about the environmental route of dissemination of AMR. Majority of the physicians agreed that AMR is a global problem and also recognize the need for initiating AMR stewardship programs. Conclusion Our study will provide effective assessment and potential insights in designing tri-faceted interventions for rationalizing antibiotics consumption thus controlling the development and dissemination of AMR. Electronic supplementary material The online version of this article (10.1186/s13756-019-0517-3) contains supplementary material, which is available to authorized users.

Plastics are polymeric materials, and their disposal is a great problem in today’s society. Large quantities of single-use plastics are used every minute throughout the world. Peroxidase enzymes play a significant role in the biodegradation of polymeric materials due to oxidoreductase capability. The objective is to determine which set of conditions optimize the production of peroxidase enzymes by Phanerochaete chrysosporium so as to degrade polymeric materials. The sequential order of parameters in terms of their relevant performance in the bioprocess was determined as urea > polyvinyl chloride > incubation time > polyethylene > veratryl alcohol > sucrose > ammonium sulfate > glucose > ferrous sulfate and polystyrene. Statistical analysis was performed by using analysis of variance which indicated the significance of model Plackett–Burman and components on the basis of F value and P value of 0.012678