ABSTRACT
The emergence of pathogenic bacteria that are resistant to several antibiotics has recently presented a significant challenge to the healthcare system. Therefore, an alternative source of antimicrobial agents is needed. The study aimed to compare the antibacterial activities of aqueous and ethanol extracts of ripe and unripe fruits of red and yellow varieties of Anacardium occidentale against Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa and Staphylococcus aureus. Cold maceration method of extraction was used using water and ethanol. Antibacterial activities of the extracts against the isolates were evaluated by agar diffusion method while minimum inhibitory concentration (MIC) was determined using broth dilution method. In the determination of the antibacterial activities of all the extracts, the highest zones of inhibition were shown by ethanolic extracts of both ripe red cashew (25 mm) and yellow cashew (26 mm) against Escherichia coli. Both the aqueous and ethanolic extracts of unripe red and yellow cashew had no antibacterial effect against Klebsiella pneumoniae and Pseudomonas aeruginosa. As well, both aqueous and ethanol extracts of ripe red and yellow cashew and ethanolic extract of ripe yellow cashew inhibited all the test organisms. Minimum inhibitory concentration ranged from 50 to 150 mg/ml. At 100 mg/ml, both ethanolic extracts of ripe red and yellow cashew were bactericidal to Escherichia coli while aqueous extract of ripe red cashew was bactericidal to Escherichia coli at 150 mg/ml. The antibacterial activities of A. occidentale apple (fruit) extracts underscore the credence to the efficacy of their use as traditional remedy against some human ailments.
Subject(s)
AnacardiumABSTRACT
Crude oil degradation efficiency can be improved because of co-metabolism that exists when bacterial consortium is applied. However, because of possible vulnerability to environmental conditions and/or antagonistic interactions among members of the consortium, the degradation efficiency can be hampered. In this laboratory-based study, the biodegradation potentials of pure bacterial isolates namely Pseudomonas aeruginosa strain W15 (MW320658), Providencia vermicola strain W8 (MW320661) and Serratia marcescens strain W13 (MW320662) earlier isolated from crude oil-contaminated site and their consortium were evaluated using 3% crude oil-supplemented Bushnell Haas media. The efficiency was evaluated based on the viable cell count, biosurfactant analyses, percentage hydrocarbon degradation using gravimetric analysis and gas chromatography-mass spectrophotometry (GC-MS) analysis. There was decline in the population of W13 and predominance of W15 in the consortium as the incubation period progressed. Accelerated biodegradation of the crude oil hydrocarbons through co-metabolism was not achieved with the consortium; neither was there any improved resilience nor resistance to environmental changes of strain W13. The GC-MS analyses showed that the highest degradation was produced by W15 (48.23%) compared to W8 (46.04%), W13 (45.24%) and the Consortium (28.51%). The biodegradation of the crude oil hydrocarbons by W15, W8, W13 axenic cultures and their consortium treatments demonstrated that the bacterial constituent in a consortium can influence the synergistic effect that improves bioremediation. Future research that focuses on evaluating possible improvement in bioremediation through maintenance of diversity by continuous bioaugmentation using vulnerable but efficient degraders in a consortium is necessary to further understand the application of consortia for bioremediation improvement.
