Composite polymer coated magnetic nanoparticles based anode enhances dye degradation and power production in microbial fuel cells.

Combined power generation and waste degradation through microbial fuel cell (MFC) technology is emerging as an attractive solution for controlling pollution in water bodies. Cyanobacteria as fuel cell catalysts for such shared energy activities are not well studied even though these possess robust metabolic systems supporting exo-electrogenicity, biodegradation of toxic compounds, and their survival under wide environmental conditions. Herein, a dual chambered (50 ml each) MFC assembled with Synechococcus sp. based bioanode and abiotic cathode for simultaneous power generation and Mordant orange dye degradation is reported. The anode was prepared by encrusting chemically synthesised magnetic nanoparticle (MNP) of size 8.4 ±â€¯0.2 nm with magnetization of 69 emu g-1on Toray carbon paper (TCP). The MNPs were encapsulated with aniline and pyrrole composite polymers to facilitate biofilm formation and cellular electron flow to the anode as confirmed by advance microscopic and voltametric techniques, respectively. The MFC with the dye mixed acetate produced current of 14.04 ±â€¯5.5 A m-3 with a maximum power density of 4.9 ±â€¯0.5 W m-3 (at cell voltage of 0.494 ±â€¯0.05 V), which was 18% higher than the control (without dye). The MFC produced a high OCP of 0.949 ±â€¯0.07 V and offered to decolorize 68.5% and degrade 89% of the dye following 216 h of its operation as confirmed by photometry (λ385 nm) and LC-MS/MS analyses, respectively. The efficient dye degradation is attributed to the bioanode for secreting high level of reactive oxygen species. The composite polymer coated MNPs anode with cyanobacterial biofilm is therefore, a highly efficient construct for enhanced azo dye degradation and associated power generation in a MFC system.

Investigating the therapeutic potential of herbal leads against drug resistant Listeria monocytogenes by computational virtual screening and in vitro assays.

Listeria monocytogenes, a Gram-positive opportunistic food-borne pathogen, naturally resistant to many antibiotics and acquired resistance may be a concern in the nearer future. Hence, there is a scope for screening of novel therapeutic agents and drug targets, toward the treatment of fatal listeria infections. The SecA homologs, SecA1 and SecA2 are the essential components of the general secretion (Sec) pathway, a specialised protein export system, present in L. monocytogenes. This study evaluates the use of botanicals against L. monocytogenes MTCC 1143 by considering SecA proteins as probable drug targets by high-throughput screening approaches. The 3D structure of SecA proteins with good stereochemical validity was generated by comparative modelling. The druglikeness and pharmacokinetic properties of 97 phytoligands identified through the extensive literature survey were predicted for druglikeness and ADMET properties. The inhibitory properties of best candidates were studied by molecular docking. The effect of the selected candidate molecules were further analysed in vitro well diffusion and cell aggregation assays. The antibiotic sensitivity profiling applied to L. monocytogenes MTCC 1143 using clinically relevant antibiotics showed that the bacteria became drug resistant to many tested antibiotics. The virtual screening suggested that .05 M cinnamic aldehyde from Cinnamomum camphora and 1, 2-Epoxycyclododecane from Cassia auriculata were identified as potential SecA inhibitors. The well diffusion assays suggested that the selected herbal substances have antibacterial activities. Further, preliminary validation suggested that incorporation of cinnamic aldehyde and methanolic or ethyl acetate extract of C. auriculata in broth medium shows growth reduction, misassembly and cell aggregation. This indicates the inhibition of SecA targets.