1.1 Introduction
Surfactants are amphipathic molecules which reduce surface tensions of viscous liquid by forming aggregate structures such as micelles (Bodour and Miller-Maier, 2002). Due to their nature and properties, they are widely used as emulsifiers for agricultural, food, cosmetic, pharmaceutical and industrial activities (Brooijmans et al., 2009). Also, they can be used as moistening agents, dispersing agents, emulsifiers, foaming agents, beneficial food elements and detergents in many industrial regions such as organic chemicals, metallurgy, mining, petroleum, petrochemicals, biological control and management and many others (Carrillo et al., 1996).
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research hypothesis and questions, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
In recent years, biosurfactants which are considered as one of the high values of microbial products have gained considerable interest. Biosurfactants have advantage over synthetic surfactants due to their low toxicity, specificity of action, simplicity of preparation and extensive applicability, bioavailability, structural diversity, specific activity at extreme salinity, temperatures and pH (Banat, 2005).
Biosurfactants which are produced by microorganisms are known to reduce the surface tension of viscous liquid. Among the roles of biosurfactants is solubilization of hydrophobic substrates especially petroleum. River Rido is a point where petroleum-rich effluents from Kaduna Refinery and Petrochemical Company are discharged. Biosurfactants are amphipathic compounds produced in living surfaces, mostly on microbial cell surfaces or excreted extracellular hydrophobic and hydrophilic moieties that confer the ability to accumulate between fluid phases, thus reducing surface and interfacial tension at the surface and interface respectively (Franzetti et al., 2010). These compounds are produced during the growth of microorganisms on water soluble and water insoluble substrates (Rosenberg and Ron, 2008). Microorganisms utilize a variety of organic compounds as the source of carbon and energy for their growth. When the carbon source is an insoluble substrate like a hydrocarbon, microorganisms facilitate their diffusion into the cell by producing a variety of biosurfactants. These bacteria excrete ionic surfactants which emulsify the hydrocarbon substrates in the growth medium. Many bacteria have been associated with the production of biosurfactants. Some examples of such bacteria isolated by Mulligan and Eekhari (2003) include Pseudomonas species and Bacillus species. Also, Nwilo and Badejo (2005) isolated Corynebacterium sp. DDV1, Flavobacterium sp. DDV2, Micrococcus roseus DDV3, Pseudomonas aeruginosa DDV4, Klebsiella pneumoniae strain IVN51 from hydrocarbon-polluted soil in Ogoniland, Nigeria. Many properties of microbial surface active compounds such as emulsification, dispersion, foaming, wetting and coating make them useful in physicochemical and biological remediation technologies of both organic and metal contaminants (Atlas, 2007).
Biosurfactants increase the bioavailability of hydrocarbon for hydrocarbonoplastic bacteria already present in the polluted water resulting in enhanced growth and degradation of oil spills by these hydrocarbon- degrading bacteria already present in polluted water (Akpofure et al., 2000). In heavy-metal polluted soils, biosurfactants form complexes with metals at the soil interface, which is followed by desorption of the metal and removal from the soil surface leading to the increase of metal ions concentration and their bioavailability in the soil solution.
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to assess the Screening and Isolation of Bacteria with Potential to Produce Biosurfacant from Oil Contamination.
1.3 Statement of Problem
Investigation reveals the problems of the research work which entails that, Nigeria has witnessed a lot of oil spills from the past which has made livelihood unbearable for people living in communities affected by such spills. Also, the discharge of effluents from the refineries into nearby rivers has increased the risks of locals who depend on the polluted rivers as their source of drinking water, cooking, fishing and agricultural purposes. Clean-up of such pollutants has not been achieved as previous studies on the area have shown increasing levels of hydrocarbon on surrounding plants and water body (Chen et al., 2012).
1.4 Aim and Objectives of Study
The aim of the study is to screen and Isolate the Bacteria with Potential to Produce Biosurfacant from Oil Contamination. In achieving this aim, the following specific objectives were laid out as follows:
- To screening and Isolation of Bacteria with Potential to Produce Biosurfacant from Oil Contamination
- To isolate biosurfactant producing bacteria from oil contaminated sites.
- To isolate the potential biosurfactant producing bacteria based on their capability of reduction in surface tension and emulsification
- To determine the growth of selected isolate on phenanthrene amended media as possible indicator for bioremediation of hydrocarbon contaminated sites.
- To isolate and screen bacteria, capable of producing biosurfactants from River Rido, Kaduna, Nigeria.
1.5 Significance of Study
The study will be a useful tool for various environmental and industrial processes, especially in the area of bioremediation of oil spills. This study will be of immense benefit to other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.
1.6 Scope of Study
The study focuses on the Screening and Isolation of Bacteria with Potential to Produce Biosurfacant from Oil Contamination using River Rido, Kaduna, Nigeria as a case study
1.7 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet).
1.8 Definition of Terms
Isolates: isolate simply means cause (a person or place) to be or remain alone or apart from others.
Phytochemical: This is a substance produced mainly by plants, and these substances have biological activity.
Component: it simply means one part of a whole thing.
Antibacterial: Anything that destroys bacteria or suppresses their growth or their ability to reproduce. Heat, chemicals such as chlorine, and antibiotic drugs all have antibacterial properties.
Effect: a change which is a result or consequence of an action or other cause.
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