Open Access Original Research Article

Manganese Peroxidase from Trichoderma harzianum and Increasing Its Efficiency for Phenol Removal from Wastewater

Hamed M. El-Shora, Mohsen E. Ibrahim, Reyad M. El-Sharkawy, Mohamed R. Elmekabaty

Journal of Advances in Microbiology, Page 1-12
DOI: 10.9734/JAMB/2017/36798

Manganese peroxidase (MnP) was isolated and purified from T. harzianum. The free and immobilized enzyme was activated by thioglycolate and reduced glutathione (GSH). After treatment with thioglycolate, the Vmax values for the free, alginate-immobilized MnP (alginate-E) and chitosan-immobilized MnP (chitosan-E) were 24.9, 27.9 and 32.6 Umg-1 protein, respectively. While, the Km values were 0.06, 0.053 and 0.071 mM. The Vmax values for the three forms of MnP in presence of GSH were 25.6, 26.9 and 33.7 U mg-1protein, respectively but Km values were 0.077, 0.065 and 0.11 mM. Free and immobilized forms were inhibited by o-phenanthroline, α,α-dipyridyl and ethylene glycol tetraacetate (EGTA). IC50 values for the free, alginate-E and chitosan-E in presence of o-phenanthroline were 0.6, 0.94 and 1.7 mM. In case of α,α-dipyridyl the values were 0.63, 0.7 and 0.89 mM. However, with EGTA the values were 0.77, 0.9 and 1.4 mM, respectively. Free and immobilized MnP expressed potentiality to remove phenol with T0.5 of 4.2, 2.95 and 1.5 h for free, alginate-E and chitosan-E, respectively. Our study reports an effective method to increase the catalytic efficiency of MnP using thiols. In addition, immobilized MnP from Trichoderma harzianum can be used for biotechnological application in removal of phenol from wastewater.

 

Open Access Original Research Article

Salmonella and Listeria Associated with Street Vended Watermelon and Pawpaw Sold in Calabar Metropolis

G. E. John, J. A. Lennox, J. T. Johnson, H. Peters, G. E. Umoafia

Journal of Advances in Microbiology, Page 1-6
DOI: 10.9734/JAMB/2017/34532

Fresh cut street vended watermelon and pawpaw was analyzed for possible contamination with Salmonella and Listeria species was understudied using standard microbiological techniques. A total of twenty samples, (10) of pawpaw and (10) of watermelon were obtained from four different vendors located in Etta-Agbo, Watt, Goldie and Marian market. These were analyzed using the Compact Dry Plate, chromogenic media for the direct detection of these organisms selectively. The results revealed a high contamination level of the samples with Salmonella spp whereas all the pawpaw and watermelon samples analyzed were free of Listeria spp. The mean Salmonella spp count ranged between 2.1X103 to 5.7x105 cfu/g. The presence of this organism in the samples analyzed is a reflection of unwholesomeness and gross contamination of the fruits and are therefore unsafe for human consumption.

 

Open Access Original Research Article

The Antibacterial Potency of Alkaloid and Saponin Extracts from Solanum macrocapon (Garden Egg)

V. A. Ajibade, M. F. Ibiyemi

Journal of Advances in Microbiology, Page 1-5
DOI: 10.9734/JAMB/2017/34488

The antibacterial potency and efficacy of alkaloid and saponin extracts from Solanum macrocapon (Garden egg) were investigated. The susceptibility of bacteria strains viz were Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa against the two extracts was determined using disk diffusion methods with different concentration (10 – 0.625 mg/mL). All the bacteria were susceptible to both alkaloid and saponin with different ranges of zone of inhibition at concentration of 10 mg/mL. The susceptibility of the bacteria to alkaloid with zone of inhibition for Escherichia coli (14.00 mm), Staphylococcus aureus (12.00 mm), Pseudomonas aeruginosa (10.00 mm) and susceptibility of the organisms to saponins with zone of inhibition for Pseudomonas aeruginosa (21.00 mm), Staphylococcus aureus (12.00 mm) and Escherichia  coli (10.00 mm). The minimum inhibitory concentration (MIC) of the alkaloid and saponins crude extracts were observed at 1.25 mg/mL respectively. The most susceptible bacteria to saponin and alkaloid were Pseudomonas aeruginosa and Escherichia coli respectively.

 

Open Access Original Research Article

Bacterization of Biostimulant (Brewers Spent Grains) on Hydrocarbon Degradation of Crude Oil Contaminated Garden Soil

Umana, Senyene Idorenyin, Bassey, Maria Paul, Uko, Mfoniso Peter

Journal of Advances in Microbiology, Page 1-19
DOI: 10.9734/JAMB/2017/36552

The influence of bio-stimulants (Brewers Spent Grains - BSG) on hydrocarbon degradation of bacteria used in the remediation of oil-contaminated soil was evaluated using standard microbiological techniques. The result revealed that the test soil contained 2.0 x107cfu/g total heterotrophic bacteria counts (THBC); of which 4.0 x102 cfu/g were oil degrading bacteria (ODB). The values of ODB/THBC ratio recorded for soil sample was less than one; and indication with a system with low level of hydrocarbon pollution. However, results obtained when microbially (B. subtilis) -augmented bio-stimulants were used in a Bacterization-Biostimulation (BB) remediation protocol revealed enhanced degradation of crude oil and it components. Viable cell measurement showed that the higher the biostimulants/contaminant (BC) - ratio employed the more the heterotrophic activity but less hydrocarbonoclastic activity. However, results have shown that soil contamination with crude oil drastically reduced the population of denitrifying bacteria but increased the population of oil degrading bacteria in soil but has concentration-dependent effects on the densities of heterotrophic bacteria. For soils remedied for 8 weeks with bacterized - BSG, the degradation rates were remarkably high and near 100% as against 44.02% recorded for the control (treatment with spent grains alone). This shows that biostimulation was better when "cropped" with oil degrading bacterium. The best degradation (99.09%) was achieved when 1% of BSG was applied (2.08%) at a BC ratio of 0.48: 1 which induced oil degraders’ growth rate and generation time of 0.00077 and 898.83 h-1 in 8 weeks respectively.  Beyond these ratios the treatments created “diauxic influence”, retarding the growth and activities of hydrocarbonoclastic bacteria while heterotrophic bacteria proliferate. The study revealed that augmenting biostimulants with strong strains of hydrocarbons degrading bacteria would stimulate the activities of indigenous degraders and ensure a hasten natural attenuation process in contaminated ecosystems. Longer incubation would certainly have led to complete or higher hydrocarbon degradation when hydrocarbonoclastic degradation enters the second log phase. Enhanced remediation with brewer's spent grains using BB protocol is strongly recommended but will be sustainable if the organic amendment stabilized with a fibre-rich carrier.

 

Open Access Review Article

Baculoviruses: Emerging Frontiers for Viral Biocontrol of Insect Pests of Agricultural Importance

O. I. Afolami, M. K. Oladunmoye

Journal of Advances in Microbiology, Page 1-7
DOI: 10.9734/JAMB/2017/35927

Accumulated evidences gathered over recent decades demonstrated that Baculoviruses (Occlusion body forming nucleopolyhedroviruses and the host specific granuloviruses) have proven Biocontrol activities on insect and pests of agricultural importance while being non-pathogenic to humans. These studies have laid the foundations for the launch of several trials phases using Baculoviruses on specific insect pests for their efficacy as viral Biocontrol agents. After a brief overview of the biology of Baculoviruses, this review focuses on the studies which unraveled the Biocontrol properties of these agents and supported their use as biopesticides of insect pests resistant to chemical pesticides. Furthermore, this review emphasizes the development of more complex Baculovirus treatment strategies aimed at enhancing formation of occlusion bodies, accelerated virus replication of infective budded forms in insect hosts and improvement of direct lethal effects in several insect developmental forms as necessary tools for increased efficacy in viral Biocontrol of insect pests of agricultural importance. However, the review also addressed the key challenges that remain towards a more efficient use of Baculoviruses as biopesticides, and discuss how a better understanding of the virus life-cycle of and the cellular factors involved in virus infection, replication and cytotoxicity may promote further development of integrated pest management involving viral biopesticides and chemical insecticides to open up new prospects for treatment of plant diseases of economic importance.