2 research outputs found
Antimicrobial and Antioxidant Properties of a Bacterial Endophyte, Methylobacterium radiotolerans MAMP 4754, Isolated from Combretum erythrophyllum Seeds
This study reports on the isolation and identification of Methylobacterium radiotolerans MAMP 4754 from the seeds of the medicinal plant, Combretum erythrophyllum, for the purposes of investigating antimicrobial and antioxidant activities from this endophyte. The strain identity was confirmed by 16S rRNA-based phylogeny and Scanning Electron Microscopy (SEM). Ethyl acetate and chloroform (1 : 1 v/v) extracts from the endophyte were tested for antimicrobial and antioxidant activity on a total of 7 bacterial species (3 Gram-positive and 4 Gram-negative) using the standard Minimum Inhibitory Concentration (MIC) protocol and Quantitative Radical Scavenging activity using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. The MICs were recorded at 250 μg/mL for B. subtilis ATCC 19659, B. cereus ATCC 1076, E. coli ATCC1053, and 62.5 μg/mL for K. oxytoca ATCC 13182 and M. smegmatis ATCC 21293, while an IC50 of 5.65 μg/mL was recorded with the DPPH assay. Qualitative phytochemical analysis was positive for alkaloids, flavonoids, and steroids. Gas chromatography/mass spectrometry (GC/MS) analysis revealed the presence of 9-octadecene, 2,4-dinitrophenyl acetate, and 2(5H)-furanone, which have been previously reported for the targeted activities. M. radiotolerans MAMP 4754 tested positive for antimicrobial and antioxidant activity and this is linked to the production of plant-derived secondary metabolites by this strain
Cloning of the cnr operon into a strain of Bacillaceae bacterium for the development of a suitable biosorbent
In this study, a potential microbial biosorbent
was engineered to improve its capacity to remediate heavy
metal contaminated water resources. A Bacillaceae bacterium
isolated from a mining area was transformed with a
plasmid carrying the (pECD312)-based cnr operon that
encodes nickel and cobalt resistance. The bioadsorption
ability of the transformed strain was evaluated for removal
of nickel from metallurgical water relative to the wildtype
strain. Results showed that transformation improved the
adsorption capacity of the bacterium by 37 % at nickel
concentrations equivalent to 150 mg/L. Furthermore it was
possible to apply prediction modelling to study the bioadsorption
behaviour of the transformed strain. As such, this
work may be extended to the design of a nickel bioremediation
plant utilising the newly developed Bacillaceae
bacterium as a biosorben