Major Problem Facing The world Today and Has Assumed Global Dimension

Major Problem Facing The world Today and Has Assumed Global Dimension

Background of Study:

  Apart from wars, terrorism, epidemics, famine and natural disasters, pollution of environment is a major problem facing the world today and has assumed global dimension.

  In Nigeria, the scenario is worse as the air, soil, water and sediments are constantly being inundated with heterogeneous substance that degrades the environment.

  The matter is worst in the Niger Delta Region (hub of petroleum activity in Nigeria) as the fragile ecosystem is under severe threat largely due to lack of commitments by both international and indigenous oil operators to industry best practices; non-enforcement of environmental laws and regulations and absence of patriotism by perceived marginalized citizens of the region.

  Thus, the region is massively polluted and the consequences are that, today, we breath polluted air, drink polluted water, eat contaminated food and live on polluted land.

  These have brought issues of environmental and public health to the front burner.

Assumption

·       Prolonged exposure of microbial isolates to ambient humic substance has a modulating influence that can produce a shift in generic and metabolic diversity.

Justification of Study:

Ø The study was conceived as a way of addressing the current environmental challenges in the Niger Delta and involved researches on sediment (Subset of aquatic system)

Ø Highlight impacts of humic substances on ecosystem microbial processes.

Ø Document and provide baseline data on microbiological and physicochemical attributes of the humic freshwater.

Ø Provide updated information and open new frontiers in studies on microbial degradation of some priority pollutants.

Ø Provide better understanding in bioremediation challenges involving PAHs and crude oil contamination in humic freshwater ecosystem.

Goal of the Study:

The goal of this study was not to repeat what has already been done in other ecosystem but to focus on the specificities of humic sediments of freshwater ecosystem, with a view to generating data and information needed to fill existing knowledge gaps and to suggest or provide some potential new direction for future researches in area of bioremediation. Specifically, we set out to evaluate crude oil and PAHs degradability of bacteria and yeasts isolated from sediment of black water ecosystem of Eniong River Itu, Nigeria.  

Research Objectives

2.0:                                      Methodology

Study Area

Humic freshwater Eniong River system flowing as a tributary of the  course of the Cross River located in Itu L.G.A and lying between latitudes 5⁰ 12¹N -5⁰ 22¹ N and longitude 7⁰ 54¹ E – 80 2¹E.

Materials

  Crude oil (Bonny light) specific gravity 0.818g/cm³ sourced from an oil servicing outfit located in Eket, Akwa Ibom state.

  Representative non-labelled PAHs (Naphthalene and anthracene) Radiochemical purity 98% - Aldrich chem. Co. USA.

  Sediment collection

·       With the aid of a steel grab sampler with grab cup measuring 38cm x 29cm having a combined weight of 3kg deployed connected to a winch via a 16mm marine rope from a boat.

Analytical Variables

§  Physicochemical properties

§  Total Petroleum hydrocarbon     - GC/FID (Aceves et al.,1988)

§  PAH content in sediment    - GC/FID (Olajire et al., 2005)

§  Humic acid content in sediment – Gravimetric Method (Barot and Beloa, 2009)

Microbiological Analyses

Ø  Total heterotrophic bacteria and yeasts in sediment –serial dilution and pour plates on nutrient agar and SDA for bacteria and yeast respectively (Vincent et al, 2011)

Ø Sequential enrichment for selections of crude oil utilizing bacteria and yeasts (Tian et al. 2008). Bacteria and yeasts on mineral salt medium enriched with 1% -4% (v/v ) filter sterilized crude oil placed on a rotary shaker at 150pm in the dark for 3 week at 28 20⁰C.

·       PAH utilizing bacteria and yeasts selected on mineral salts enriched with 1% -4% (W/V) model PAH compounds (Naphthalene and anthracene) placed under similar conditions.

Ø Screening for crude oil utilizing bacteria and yeasts by vapour phase transfer (Okpokwasili and Amanchukwu, 1998)

·       Screening for PAH utilizing bacteria and yeasts by modified method of Kiyohara and Nagao (1978).

·       Purification of isolates achieved by repeated sub-culturing using streak plating technique.

·       Pure bacteria colonies stocked on NA slants and yeasts on corn meal agar slant and preserved under refrigeration at 4⁰C.

·    Bacteria characterized presumptively based on morphology, cultural and physiologic attributes.

·    Gram staining method of Stewart and Beswick (1997) adopted. 

·    Biochemical test for bacteria included catalase, oxidase, urease spore stain, motility. MR-VP and sugar fermentation according to Cruickshank, Duguid, Marmuon and Swan (1975).

·    Bacteria attributes collated and identification done by comparing with characteristics of known taxon using the schemes of Holt et al., (1994).

·    Pure cultures of yeasts characterized and identified on the basis of their cultural and morphological properties as well as sugar utilizing potentials according to Sampson, Hoekstra and Vanooerschiot, (1984).

Microbial Degradation

Ø Time – course degradation performed and growth of isolates on rotary shaker (120rpm) indirectly monitored by measuring OD, TVC and pH at 3 days interval for 21 days at room temperature.

·       Degradation of crude oil by bacteria studied in 200ml mineral salt medium supplemented with 10ml of sterile crude oil.

·       Degradation of crude oil by yeast studied in 200ml Bacto Bushnell -Hass broth supplemented with 5% crude oil and 2% (v/v) redox indicator.

·       Degradation of PAH by bacteria and yeasts.

Above procedure used but supplemented with 10g of crystalline PAH.

Ø Growth Kinetics Determination

n=3.3 log  

Where n= number of generation

B = organism counts at zero time

B = number of organism at end of a given period.

Generation Time G

G = 

·       Determination of persistent residue after degradation by chromatographic profiling.

·       Biodegradation Model.

Model derived from the relationship y=a - kt

And formulated as

Where y = amount degraded

a     = initial concentration

t      = time in days

k     = first order reaction rate reaction.

Determination of Heterotrophic Attributes

Biosurfactant Production

·       Haemolytic activity (Yourseuf et al, 2004)

·       Emulsification index (Bodour et al., 2004) phosphate solubilization using pikovskaya medium (Sharma 2009).

·       Influence of hydrocarbon – degrading isolates on some soil physical and chemical properties.

·       Greenhouse determination of soil toxicity amelioration using Zea mays

·       Plasmids were profiled and cured using methods described by Ehrenfeld and Clewell (1987); Sheikh et al (2003)

·       Genomic analyses and gene sequencing.