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Aim: Microbial air quality over illegal refuse dump sites in Port Harcourt, Nigeria, was conducted to assess the aero-microbial contaminant of dumpsite to the closest neighbourhood and the harmful distance. Place and Duration of Study: The dump sites were located at oil mill market (Latitude 4.8578 N4°51'28.06344'' Longitude 7.06653 E7°3'59.50152'') and Iloabuchi Timber market (longitude N4.790191, latitude E6.988416) all in Port Harcourt, South South Nigeria. The samplings were carried out between June (dry season) and July (wet season) 2018. Methodology: The microbial concentration of air around the dump sites were measured using the “sedimentation method” that involved exposing different sterile Petri dishes containing nutrient agar, Mac Conkey agar, and sabauroud dextrose agar to the air for ten minutes. The exposures were carried out at different locations within and around the dump site viz; Top of the dumpsite at different altitude (3ft, 6ft and 9ft above dump surface), 0m, 10m away from the dumpsite, and at the nearest neighbourhood which is about 100m away from the dumpsite. These samplings were carried out to the left and right sides of the dump sites. The samplings were carried out between June and July 2018, so as to compare the microbial load between the dry and wet seasons. Result: The microbes at the dump sites were in most cases higher than the microbes at the neighbourhood (100m away to the left and right). Seasonal occurrence revealed that microbial load in air during the dry season (6.037±0.92 cfu/min-m2) is higher than during the wet season (1.814±0.19 CFU/min-m2). Percentage variation amongst heterotrophic bacterial isolates revealed, Staphylococcus massiliensis (47.90%) > Erwinia psidii (18.24%) > Shigella dysenteriae (18.17%) > Bacillus simplex (6.08%) > Saminicoccus kunminingensis (3.23%) > Corynebacteriun afermentans (3.00%) > Paenibacillus celluositrophycus (2.25%) > Streptococcus parasuis (5.26%); percentage variation amongst enteric bacterial isolates revealed, Staphylococcus aureus (28.57%) > Geobacillus stearothermophilus (20.82%) > Escherichia coli (8.16%) and Bacillus carboniphilus (8.16) > Salmonella enterica (6.94%) > Bacillus smithii (6.12%) > Macrococcus brunensis (4.49%) > Lactobacillus kitasatonis (3.67%) > Klebsiella pneumonia (2.86%) > Staphylococcus saccharolyticus (2.45%) > Bacillus badius (2.04%) = Paenibacillus lautus (2.04%) > Brevibacillus laterosporus (1.63%). The fungal distribution revealed, Aspergillus fumigatus (16.62%) > Microsporium canis (15.40%) > Aspergillus flavus (14.75%) > Aspergillus niger (10.99%) > Conidiobolus coronatus (10.19%) > Pheaocremonium parasiticum (6.97%) > Fusarium chlamydosporium (6.70%) > Trychophyton etriotrephon (5.63%) > Trychophyton quinckeanum (4.02%) > Lichtheeimia corymbifera (3.57%) > Cladosporium cladosporioides (2.95%) > Saccharomyces spp (2.68]%). Conclusion: The presence of microbial pathogens such as Escherichia coli, Staphylococcus aureus, Bacillus spp, Klebsiella pneumonia, Salmonella enterica and Aspergillus species, is alarming and of great health concern. The harmful distance exceeds 100m away from the dump site which encroached 30 meters into residential areas. This research work revealed the relevance of Environmental air monitoring in any Governmental Waste Management System and the potential hazard of open dump system of waste disposal around residential area.

Aim: To assess the Mycoremediation potential of Mucor racemosus and Aspergillus niger in open field crude oil contaminated soils in Rivers State, Nigeria.  Study Design: The study employs experimental design, statistical analysis of the data and interpretation. Place and Duration of Study: Rivers State University demonstration farmland in Nkpolu-Oroworukwo, Mile 3 Diobu area of Port Harcourt, was used for this study. The piece of land is situated at Longitude 4°48’18.50” N and Latitude 6ᵒ58’39.12” E measuring 5.4864 m x 5.1816 m with a total area of 28.4283 square meter. Mycoremediation process monitoring lasted for 56 days, analyses were carried out weekly at 7 days’ interval. Methodology: Five (5) experimental plots were employed using a Randomized Block Design each having dimensions of 100 x 50 x 30 cm (Length x Breadth x Height) and were formed and mapped out on agricultural soil, each plot was contaminated with 22122.25g of Crude Oil except Control 1 and left fallow for 6 days after contamination for proper contamination and exposure to natural environmental factors to mimic crude oil spill site. On the seventh day bio-augmentation process commenced using two (2) fungal isolates namely Aspergillus niger [Asp] and Mucor rasemosus [Muc]). Two (2) control plots (P1: Uncontaminated and unamended soil - CTRL 1 US) and P2: Crude Oil contaminated but unamended soil - CTRL 2 CS); P3 = P5 were contaminated and amended/bioaugmented (P3: CS+Asp, P4: CS+Muc, P5: CS+Asp+Muc respectively. Soil profile before and after contamination was assayed while parameters like Temperature, pH, Nitrogen, Phosphorus, Potassium and Total Petroleum Hydrocarbon (TPH) contents were monitored throughout the experimental period. Microbial analyses such as Total Heterotrophic Bacteria (THB), Total Heterotrophic Fungi (THF), Hydrocarbon Utilizing Bacteria (HUB) and Hydrocarbon Utilizing Fungi (HUF) were recorded. Bioremediation efficiency was estimated from percentage (%) reduction of Total Petroleum Hydrocarbon (TPH) from day 1 to the residual hydrocarbon at day 56 of bio- augmentation/ biostimulation plots with the control. Results: Results revealed actual amount of remediated hydrocarbon and % Bioremediation Efficiency at 56 days in the different treatment plots (initial TPH contamination value of 8729.00mg/kg) in a decreasing order as follows: CS+Muc (8599.19mg/kg; 33.66%) > CS+Asp+Muc (8357.31mg/kg; 33.04%) > CS+Asp (8341.58mg/kg; 32.98%) > CTRL 2 -CS (Polluted soil without amendment) (81.06mg/kg; 0.32%). Microbiological results After fifty-six (56) days of bioremediation monitoring; %HUB were as follows; CS+Asp+Muc (45.30%) > CS+Asp (40.32%) > CS+Muc (35.01%) > CTRL 2 –CS (30.43%) > CTRL 1 – US (0%). These results indicate that the presence of the contaminated crude oil stimulated and sustained the growth of Hydrocarbon Utilizing Bacteria (HUB) in the contaminated plots (P2 - P3); more so, the higher growth in the enhanced bio-augmented plots (P3 – P5) shows the positive impact of fungal bio-augmentation in bioremediation of crude oil polluted soil. It was further observed that treatment plots with higher HUB or HUF had higher percentage (%) bioremediation efficiency; that is, the higher the sustained HUB and HUF population, the higher the %Bioremediation process. Hydrocarbon Utilizing Bacteria (Log10 CFU/g): CS+Asp (4.20) (Day 35) > CS+Muc+Asp (4.18) (Day 35) > CS+Muc (4.08) (Day 28) > CTRL 2 – CS (3.95) (Day 21) > CTRL 1 – US (3.78) (Day 35). (Fig. 3). Hydrocarbon Utilizing Fungi (Log10 CFU/g): CS+Asp (4.68) (Day 35) > CS+Muc+Asp (4.58) (Day 35) > CS+Muc (4.48) (Day 35) > CTRL 2 – CS (4.23) (Day 21) > CTRL 1 – US (2.85) (Day 42). Conclusion: Study showed that bioremediation of crude oil-contaminated soils with Bioaugmenting fungus singly may be more effective than combination with others depending on the type of substrate used, nature of the hydrocarbon utilizing organism and environmental conditions prevalent as seen in Mucor racemosus having higher bioremediation potential than when combined with Aspergillus niger. Notably, Hydrocarbon Utlilizing Bacteria (HUB) and Hydrocarbon Utilizing Fungi (HUF) which are the key players in Bioremediation has its peak count value on Day 35, this confers that nutrient renewal on bioremediation site should be at interval of 35 days for continuous effective bioremediation of hydrocarbon pollutants. It is therefore recommended that single microbes of high bioremediation potential could be used since its more effective than consortium of many hydrocarbon utilizing microbes. Also, nutrient or bio-augmenting microbes’ renewal on bioremediation site should be at an interval of 35 days for continuous effective bioremediation of hydrocarbon pollutants.

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Aim: This study was carried out to investigate the Susceptibility of Candida albicans, Staphylococcus aureus and Escherichia coli to extracts from young and mature mango (Magnifera indica) leaves and stem-bark of the same plant.                                                                                Study Design: The study employed statistical analysis of the data and interpretation.                                      Place and Duration of Study: Young and mature mango leaves and stem-barks were collected from the Botanical Garden, Kenule Beeson Saro-Wiwa Polytechnic, Bori, Nigeria, and taken to the laboratory for analyses.                            Methodology: The samples were dried in an oven at 80oC for 3 days. Thereafter, 50 g of each ground mango leaves and stem-bark (young and mature of the same plant) were soaked separately in 500 ml of water, ethanol (95% v/v), and acetic acid (99.9% v/v) for another 3 days. The soaked materials were filtered through Whatman No. 1 filter paper into sterile beakers and evaporated to dryness in a water-bath at 80oC. The dried extracts obtained were reconstituted with water at concentrations of 100, 75, 50 and 25 mg/ml. Test organisms, Candida albicans, Staphylococcus aureus and Escherichia coli were obtained after proper laboratory screening of isolates from the diagnostic laboratory of the Rivers State University Teaching Hospital, Port Harcourt, Nigeria, for confirmation of identity and storage in universal bottles in a refrigerator. Sensitivity tests were carried out with the agar well diffusion method against the test organisms, using tetracycline as standard control drug (for bacteria) and fluconazole (for Candida), with cultures incubated accordingly. The measured zones of inhibition were compared with the controls and interpreted as resistant, intermediate, or susceptible to mango extracts in accordance with the interpretive guidelines published by the National Committee for Clinical Laboratory Standards (NCCLS). Assays for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also carried out. Results: Results obtained showed that Escherichia coli was completely susceptible to acetic acid young leaf and young bark extracts at 100 mg/ml concentrations. Staphylococcus aureus was susceptible only to Acetic acid young leaf extract at 100 mg/ml. For Candida albicans complete susceptibility was with acetic acid young bark at 100 mg/ml.  mature leaf extract (100 mg/ml ), acetic acid young bark extract (100 to 50 mg/ml ), aqueous young bark extract (100 mg/ml) and acetic acid mature   Candida albicans was susceptible to acetic acid young and mature bark extract at 100 mg/ml concentration. Minimum inhibitory concentration (MIC) values of acetic acid young leaf extract for all three organisms were 12.5 mg/ml. MIC of ethanolic young leaf extract for E. coli was 12.5 mg/ml whereas that for C. albicans was 50 mg/ml.  Minimum bacteriocidal concentration values were same as MIC. Conclusion: E. coli and S.aureus were found to be most susceptible to acetic acid young leaf and stem-bark mango extracts. For C. albicans susceptibility profiles were best with aceti acid young and mature stem-bark extracts. It was also found that mango phytochemicals have broad-spectrum antibacterial activity as well as antifungal properties. The study also reveals that young mango parts contain higher bioactive substances than mature parts. Finally, it was concluded that acetic acid extracts produced the highest antimicrobial effects whereas aqueous extracts produced the least.

Aim: This study was carried out to investigate the antibacterial properties and efficacy of mango (Mangifera indica) leaf extracts on some clinical isolates as test rganisms.                                                                Study Design: The study employed statistical analysis of the data and interpretation Place and Duration of Study: Young and mature mango leaves were collected from the Botanical Garden, Kenule Beeson Saro-Wiwa Polytechnic, Bori, Nigeria, and taken to the laboratory for analyses.     Methodology: The samples were dried in an oven at 80oC for 3 days. Thereafter, 50 g of each ground mango leaf (young and mature leaves) were soaked separately in 500 ml of water, ethanol (95% v/v), and acetic acid (99.9% v/v) respectively for another 3 days. The soaked materials were filtered through Whatman No. 1 filter paper into sterile beakers and evaporated to dryness in a water bath at 80oC. The dried extracts obtained were reconstituted with water at concentrations of 100, 75, 50, and 25 mg/ml. Test organisms, Escherichia coli, Staphylococcus aureus, Salmonella typhi, Proteus mirabilis, Bacillus cereus, and Pseudomonas aeruginosa were obtained after proper laboratory screening of isolates from the diagnostic laboratory of the Rivers State University Teaching Hospital, Port Harcourt, Nigeria, for confirmation of identity and storage in universal bottles in a refrigerator. Sensitivity tests were carried out with the agar well diffusion method against the test organisms, using tetracycline as the standard control drug, with cultures incubated accordingly. The measured zones of inhibition were compared with the controls and interpreted as resistant, intermediate, or susceptible to mango extracts in accordance with the interpretive guidelines published by the National Committee for Clinical Laboratory Standards (NCCLS). Assay for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was also carried out. Results: Results obtained showed that acetic acid young leaf extract at 100mg/ml produced 50 % susceptibility and 50 % intermediate response of test bacterial species. Generally, at 100 mg/ml, acetic acid young leaf extracts yielded 50% susceptibility and 50% intermediate response among both Gram-positive and Gram-negative bacteria. Ethanolic extracts gave 100% intermediate sensitivity of Gram-negative species and 50% each of resistant and intermediate response in Gram-positive forms. Aqueous extracts also produced no susceptibility among the test organisms as there was 100% resistance. Extracts of mature mango leaves of all solvents and at all concentrations used yielded no susceptibility response among the test bacterial species on the NCCLS scale. Minimum inhibitory and bactericidal concentrations were found to range from 25 mg/ml to 50 mg/ml. Additionally, it was observed that the sensitivity of organisms to mango extracts increased with concentration. Conclusion: In conclusion, acetic acid has a better extracting potential than ethanol and water as a solvent for the extraction of mango parts. More so, young mango leaves extracted with acetic acid possess higher broad-spectrum antibacterial properties than the mature mango leaves extracted from the same plant. It is therefore recommended that young mango leaves, extracted with acetic acid, be used for the treatment of microbial infections at concentrations not below 50 mg/ml.

Aim:The aim of the study was to evaluate the impact of organic nutrient supplements and bioaugmenting microorganisms on crude oil polluted soils. Place and Duration of Study: