Keratin waste has become an increasingly serious environmental and health hazard. Keratin waste is mainly composed of keratin protein, which is one of the most difficult polymers to break down in nature and is resistant to many physical, chemical, and biological agents. With physical and chemical methods being environment damaging and costly, microbial degradation of keratin using keratinase enzyme is of great significance as it is both environment friendly and cost-effective. The aim of this study was to extract and purify keratinase from bacterial species isolated from the soil. Among the organisms, an isolate of Bacillus velezensis, coded as MAMA could break down chicken feathers within 72 hours (h). The isolated strain produced significant levels of keratinase in mineral salt medium by supplying chicken feathers as the sole source of nitrogen and carbon. Feather deterioration was observed with the naked eye, and enzyme activity was evaluated using a spectrophotometric assay. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and zymography results revealed that the keratinase protein produced by Bacillus velezensis had a molecular weight between 40 and 55 kilo Dalton (kDa).
Background: Tuberculosis remains a major health problem with more than 3 million deaths and 9 million new cases annually. Pakistan ranks 5th in the top 22 tuberculosis burden countries. Prevalence of all tuberculosis cases is 342 per 100,000 individuals in Pakistan. Objectives: The objective of the present study was to assess the frequency and pattern of tuberculosis in a population from Khyber Pakhtunkhwa. Methods: This prospective study was conducted in programmatic management of drug resistant tuberculosis unit lady reading hospital Peshawar, Pakistan between January, 2014 and December, 2014. A total of 1330 specimens from suspected drug resistant tuberculosis patients were analyzed by light-emitting diodes-fluorescence microscopy (LED-FM). The SPSS 18 software was used for data analysis. Results: Of the 1330 drug resistant tuberculosis suspect patients tested by LED-FM microscopy, 824 (62%) were smear positive for Mycobacterium and 306 (38%) were negative. Mean age was 30.92 ± 14.91 years. Out of smear positive cases, 462 (56.1%) were female, 722 (87.6%) were previously treated, and 446 (54.1%) were in < 30 years old. A statistically significant association was observed between female gender, previous tuberculosis treatment, and age category (< 30 years) with smear positive results. Conclusions: Female gender, previous treatment, and young age (< 30 years) were significantly associated with smear positivity. Early detection and effective treatment of active tuberculosis cases is of paramount importance to reduce the burden of tuberculosis. Light-emitting diodes- fluorescence microscopy is the best method for early diagnosis of tuberculosis if performed by an experienced microbiologist, as it is reliable and inexpensive.
This study is aimed at the chemical synthesis of light-activated cobalt-doped zinc oxide and its further doping on reduced graphene oxide (RGO) and assessment of its antibacterial activity on antibiotic-resistant waterborne pathogens including Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumonia, and Pseudomonas aeruginosa. The synthesized nanoparticles were characterized via UV–vis spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The minimal inhibitory concentration (MIC) of nanoparticles portrayed a significant killing of both Gram-positive and Gram-negative bacteria. The synthesized nanoparticles were further found as active killers of bacteria in drinking water. Further, these nanoparticles were found photothermally active alongside ROS generators. The photokilling activity makes them ideal replacement candidates for traditional water filters.
This study investigated the photocatalytic degradation of pure low-density polyethylene (LDPE) and commercial-grade polyethylene (PE) films with iron-doped zinc oxide (Fe-ZnO) nanoparticles under visible light.The study was particularly focused on the role of reactive oxygen species (ROS) and the types of plastic degradation.The Fe-ZnO were synthesized using the co-precipitation method and characterized by TEM and XRD.Degradation of 6.35 cm 2 films of LDPE and commercial grade PE was tested under artificial LED light (84 lm/W) and dark in Fe-ZnO suspensions of 10 ml having concentrations ranging from 10 to 1000 g/ml.The results showed a maximum weight reduction of 13.8 % for pure LDPE films at 200 g/ml and 15 % for commercial grade PE at 1000 g/ml in 14 days.In comparison, no weight reduction was observed in the dark, which confirmed that the degradation was induced by the production of ROS moieties in visible light i.e., singlet oxygen (30.11 %), hydroxyl ions (30.45 %), and hydroxyl radicals (39.34 %).The degradation was further confirmed by FTIR with the formation of alcohols and alkenes and SEM analysis that showed visible cracks in both LDPE and PE.The study unveiled Fe-ZnO nanoparticles as an efficient substitute to degrade polyethylene under visible light.
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