Open Access Original Research Article

Antimicrobial Activity of Garlic Extract on Organisms Isolated from Tomato Rot

Grace Michael Ikon, Victor Nelson Abasiubong, Chijioke Patrick Amadi

Journal of Advances in Microbiology, Page 1-10
DOI: 10.9734/JAMB/2017/37590

Antimicrobial Activity of Garlic Extract on Organisms Isolated from Tomato Rot

Aqueous garlic extract is made up of antioxidant ingredient and has been responsible for boosting the immune system of the body; it is also used as a broad spectrum antibiotic, killing bacteria, fungus, and viruses. The microbial activities of spoilt and fresh tomato fruit was investigated using serial dilution method.

The antimicrobial activity of aqueous garlic extract against selected microorganisms isolated from spoilt tomato fruit was determined using diffusion method. The  total  heterotrophic bacteria count ranged from 4.0 X 105 cfu/g to 8.0 X 106 cfu/g and total coliform count ranged from 2.5 X105 cfu/g to 3.5 X 106 cfu/g and total fungal count ranged  from 1.0 X 105 cfu/g to 2.6 X 106 cfu/g  cfu/g. The bacteria isolated were Salmonella entercolitis, Escherichia coli, Enterococcus faecium, Pseudomonas aeruginosa, Staphylococcus aureus, Acetobacter aceti, Xanthomonas campestris, Lactobacillus  plantarum, Streptococcus pyogenes, Leuconostoc gasicomitatum, while the fungi isolates where Mucor spp, Saccharomyces cerevisae, Penicillium notatum, Aspergillus flavus. Concentrations of 10, 20, and 40 mg/ml of garlic aqueous extract were tested for their antimicrobial activity against some of the bacterial and fungal isolates from spoilt tomato. The result showed that aqueous concentrations of garlic extract between 10 to 40 mg/ml possess antimicrobial properties on the selected organism apart from A. flavus, where there is no zone of inhibition.

The presence of bacteria pathogens and fungi in tomatoes could pose a serious threat to health. Therefore treatment of tomato fruit with at least 40 mg/ml garlic aqueous extract could be used as a beneficial antimicrobial agent.

Open Access Original Research Article

pH Effect and pH Changes during Biocellulose Production by Gluconacetobacter xylinus in Moringa oleifera Tea-Sugar Medium

C. G. Dirisu, J. Rosenzweig, E. Lambert, A. A. Oduah

Journal of Advances in Microbiology, Page 1-7
DOI: 10.9734/JAMB/2017/38440

The study was carried out to determine the effect of pH and pH changes accompanying Biocellulose (BC) production by Gluconacetobacter xylinus (GX) in a Moringa oleifera tea-sugar medium. The authors adopted experimental and comparative design for the study. Moringa oleifera leaves were harvested at the front of Physics laboratory, Federal College of Education (Technical) Omoku. Nigeria. Banana was purchased from vendors in Omoku market and kept for 5-7 days to allow the development of acetic acid bacteria. Gluconacetobacter xylinus (GX) was isolated from spoiled banana and used to inoculate Moringa oleifera tea-yeast extract medium to which different concentrations of sugars-fructose, glucose and a combination of glucose and fructose were added. The pH of the medium was adjusted to pH ranging from 4-8, sterilized by autoclaving at 121°C for 15min. Media were inoculated in duplicates with 0.1 ml of GX and incubated at 30°C for 15 days to observe for cellulosic pellicle. The pellicles were extracted by alkaline hydrolysis, washed and weighed. Changes in pH were also monitored in the course of the fermentation. The Mean BC yield were 0.175±0.12, 0.182±0.12, 0.085 ±0.05, 0.025 ±0.03 and 0.018 ±0.03 at pH 4,5,6,7 and 8 respectively. pH changes during fermentation tended towards neutral or near-neutral range while it increased from an initial value of 4 and 5 to around 6. pH 7-8 of the fermenting mixture decreased with increasing sugar concentration but in the order, Glucose-fructose medium<Glucose medium<Fructose medium. The result of this study showed that Biocellulose, which is a biopolymer used for various industrial applications can be produced from a readily and sustainable source, Moringa olefera leaves with control of pH and concentration of added sugar.

Open Access Original Research Article

Molecular Characterization of ESBLs Genes among Multi-drug Resistant Klebsiella species in Ile-Ife South-West, Nigeria

O. A. Thonda, A. O. Oluduro

Journal of Advances in Microbiology, Page 1-9
DOI: 10.9734/JAMB/2017/37925

Aim: This study was carried out to determine the presence of ESBLs genes (TEM, CTX-M, SHV, AAC and OXA types of Beta-lactamases) in clinical isolates of Klebsiella species producing extended spectrum beta-lactamase.

Extended Spectrum Beta Lactamase (ESBL)-producing Klebsiella have increased rapidly and became a major problem in the area of infectious diseases. Nosocomial infections are primarily caused by Klebsiella bacteria, which leads to an increase in health care costs and mortality rate.

Methodology: A total of 166 bacteria was isolated. Resistance to different antibiotics was determined using the standard disk diffusion method. Extended spectrum beta-lactamases were screened for using disc diffusion method, confirmatory test was detected by the double disk synergy test (DDST) method and polymerase chain reaction (PCR) was used to determine blaCTX, blaOXA, blaSHV, AAC and blaTEM genes in the ESBLs positive isolates.

Results: blaTEM (31%) was the most prevalent and AAC (27%). The rates of CTX-M and SHV genes are 21% and 13% respectively.

Conclusion: Outbreak of isolates producing ESBLs can cause serious problems in the future, regarding the treatment of infections caused by this common pneumonia pathogen.

Open Access Original Research Article

Optimizing C:N Ratio, C:P Ratio, and pH for Biosurfactant Production by Pseudomonas fluorescens

P. L. Peekate, G. O. Abu

Journal of Advances in Microbiology, Page 1-14
DOI: 10.9734/JAMB/2017/38199

Aim: To optimize the combination of selected culture medium parameters so as to achieve maximum biosurfactant production from Pseudomonas fluorescens.

Study Design: (1) Culturing P. fluorescens for biosurfactant production using a glycerol-mineral salt media with variations in  ratio, carbon and phosphorus ratio (C:P ratio), and pH, (2) Screening for biosurfactant activity, (3) use of Response Surface Methodology in determining the combination of the factors that will lead to maximum biosurfactant production.

Place and Duration of Study: Department of Microbiology, Faculty of Science, University of Port Harcourt, Nigeria, between September 2016 and June 2017.

Methodology: Pseudomonas fluorescens was cultured for biosurfactant production using glycerol-mineral salt media with variations in carbon and nitrogen ratio(C:N ratio), C:P ratio, and pH. Combination of these factors was optimized via the use of Response Surface Methodology. The range of values of the factors investigated was C:N: 20–60, C:P: 10–16, pH: 5.5–8.5. Fifteen experimental runs were carried out.

Results: At the end of the experimental runs, the surface tensions of the culture broths ranged from 30.66 – 51.90 mN.m-1. The surface tensions were fitted into the generalized polynomial model for 3-factor design. The model was worked out to be Y = 296.5533 – 34.4456X1 + 0.602833X2 – 23.4019X3 – 0.0545 X1X2 + 1.088889X1X3 + 0.020417 X2X3 + 1.663333X12 – 0.00596X22 + 0.551944X32. Prediction profiles generated from this model showed that the lowest surface tension, indicating maximum biosurfactant production, was achievable at a combination of pH 5.5, C:N = 20, and C:P = 16. Use of this combination for biosurfactant production resulted in reduction of the surface tension of the broth culture from 60.04 mN.m-1 to 30.64 mN.m-1. This almost tallied with the predicted value of 30.57 mN.m-1.

Conclusion: The optimized combination avoided wastage of the carbon source. It is thus economical to carry out optimization procedures before proceeding to commercial production of biosurfactants.

Open Access Review Article

An Overview of Cultural, Molecular and Metagenomic Techniques in Description of Microbial Diversity

U. O. Edet, S. P. Antai, A. A. Brooks, A. D. Asitok, O. Enya, F. H. Japhet

Journal of Advances in Microbiology, Page 1-19
DOI: 10.9734/JAMB/2017/37951

An Overview of Cultural, Molecular and Metagenomic Techniques in Description

of Microbial Diversity

Traditional microbiology based on the culture of microorganisms has been the mainstay of microbiology for over a century and has contributed immensely to what we now know about the harmful and beneficial roles of microorganisms. However, it has a number of limitations that has hampered the full utilization of the non-culturable majority in various ecosystems. Metagenomics is a technique that bypasses the need to culture microorganisms from various samples. Unarguably, it is one of the few powerful techniques that have revolutionized every aspect of molecular biology, microbiology, microbial ecology and even beyond. Although still in its infancy, metagenomics have far reaching applications already in medicine and health care, biotechnology, environmental microbiology, bioprospecting for new products of biological origin, discovery of functional genes, evolution, to mention just a few. The various steps involved in metagenomics from sampling to sequencing have all been shown to affect the overall diversity of the sampled ecosystem. An ideal methodology should be one that produces a fair representation of the community sampled.  The rapid progress in sequencing technologies has forced its cost down per sample. This has lead to a drastic increase in the number of research projects using sequencing technologies, and databases that can store, analyse and allow retrieval of metagenomics data. With this pace of growth, we will certainly see many putative genes, proteins and pathways come alive, and also witness a number of paradigm shifts in some key concepts in traditional microbiology like taxonomy and microbial physiology.