The photocatalytic pretreatment of lignocellulosic biomass to oxidize lignin and increase biomass stability has gained attention during the last few years. Conventional pretreatment methods are limited by the fact that they are expensive, non-renewable and contaminate the anaerobic digestate later on. The present study was focused to develop a metal-derived photocatalyst that can work with visible electromagnetic spectra light and oxidize commercial lignin liquor. During this project the advanced photocatalytic oxidation of lignin was achieved by using a quartz cube tungsten T3 Halogen 100 W lamp with a laboratory manufactured TiO2-ZnO nanoparticle (nanocomposite) in a self-designed apparatus. The products of lignin oxidation were confirmed to be vanillic acid (9.71 ± 0.23 mg/L), ferrulic acid (7.34 ± 0.16 mg/L), benzoic acid (6.12 ± 0.17 mg/L) and p-coumaric acid (3.80 ± 0.13 mg/L). These all products corresponded to 85% of the lignin oxidation products that were detectable, which is significantly more than any previously reported lignin pretreatment with even more intensity. Furthermore, all the pretreatment samples were supplemented in the form of feedstock diluent in uniformly operating continuously stirred tank reactors (CSTRs). The results of pretreatment revealed 85% lignin oxidation and later on these products did not hinder the CSTR performance at any stage. Moreover, the synergistic effects of pretreated lignin diluent were seen that resulted in 39% significant increase in the methane yield of the CSTR with constant operation. Finally, the visible light and nanoparticles alone could not pretreat lignin and when used as diluent, halted and reduced the methane yield by 37% during 4th HRT.
Klebsiella pneumoniae is an opportunistic pathogen causing severe hospital-acquired infections, and it rapidly acquires multidrug resistance. Its robust biofilm formation further complicates treatment and drives interest in phage therapy. A phage UHKP was isolated from hospital sewage using an MDR K. pneumoniae strain ( KP- 03). UHKP formed clear plaques and having phage titer 2.3 × 10 9 PFU/mL. Host-range testing on 19 clinical isolates showed a narrow spectrum. Only four MDR strains ( KP- 03, KP- 05, KP- 08, KP- 11) and one K-17 serotype were lysed, with no activity on other strains or species. One-step growth analysis yielded a 30 min latent period and 85 PFU burst size. In planktonic culture, UHKP at MOI 1 stopped bacterial growth by 4 h and cleared cultures by 8 h, whereas at MOI 0.1 killing was delayed and incomplete. In static biofilm assays, UHKP eradicated 98% of 24-h and 96% of 48-h biofilm biomass by 24 h (MOI 1). Clearance of 72 – 96 h biofilms was limited (≤ 87% by 24 h). UHKP possesses an icosahedral head of 56 ± 3 nm and a short, non-contractile tail measuring around 15 ± 2 nm. Genome sequencing revealed a 62,542 bp dsDNA genome (56.6% GC) encoding 77 ORFs, and phylogenetic analysis placed UHKP in the genus Lastavirus . UHKP carries no lysogeny, toxin or antibiotic-resistance genes.
23 August 2021 in Saudi Journal of Biological Sciences
Chronic stage renal disease is a severe disease of the kidney which affects people globally. According to the global burden of diseases in 2010, this disease has caused more deaths worldwide and due to the high death rate, the ESRD (end-stage renal disease) is now ranked up from 27th to 18th range in the list. Dialysis samples were collected from the Haripur city and surrounding areas. Samples were inoculated on different selective media for bacterial growth. In addition, different biochemical tests were also performed for identification, where as the resistance genes were identified through a polymerase chain reaction. Out of the total 100 dialysis patient’s blood samples, only 17 showed the presence of gram-positive bacteria i.e., Staphylococcus aureus while two shown the presence of gram-negative bacteria i.e., Klebsiella pneumoniaeee and Pseudomonas aeruginosa. While in molecular identification two antibiotic resistance genes muc and mecA belong to the staphylococcus strain shown their presence. A high infection rate has been observed in fistula-based hemodialysis (17(77.27%)) as compares to catheter-based hemodialysis (5(22.3%) with no significant difference of incidence between the groups (p > 0.05).