SCREENING AND CHARACTERIZATION OF BACTERIA CAPABLE OF PRODUCING POLYHYDROXYBUTYRATE FROM ENGINE OIL CONTAMINATED SOIL.

CHAPTER ONE
INTRODUCTION

Background of Study
Bioplastics are natural polyesters product, produced by a range of microbes, cultured under different nutrient and environmental conditions, the polymers are usually lipid in nature and accumulated as storage materials in liquid granules which enable microbes to survive under stress or harsh conditions and also the number and sizes of the granules, the monomer composition, macromolecule structure and physico-chemical properties varies depending on the producer organism (Jose et al., 2003). Biodegradable plastics are special type of biological material which is degradable and eco-friendly in their chemical nature. Example ofbiodegradable polymer materials is the Polyhydroxyalkanoates (PHAs) family( Zhanget al., 2003).Polyhydroxyalkanoates (PHAs) are linear polyesters of repeating units of 3 hydroxyalkanoic acid monomers which can be different in their carbon chain length (Khansaaet al., 2016). PHAs are produced in nature by bacterial fermentation of lipids or sugars which are converted to CO2, the PHA granules are accumulated under limiting nutritional element conditions such as nitrogen, phosphorus, sulfur, oxygen and magnesium in the presence of excess carbon source (Khansaaet al., 2016). The main member of the PHA family is Polyhydroxybutyrate(PHB)(Mukeshet al., 2018). Polyhydroxybutyrate (PHB), a family of bio polyesters with diverse structures, is the only bio plastics completely synthesized by micro-organisms. These are natural, thermoplastic, aliphatic biopolyesters that completely meet the terms like bio-based, biodegradable, compostable or biocompatible to qualify them as Green plastics and all bioplastics have a unique property of being completely degraded to CO2 and H2O by PHA hydrolases and PHA depolymerases (Mukeshet al., 2018). Generally, several factors such as culture temperature, pH and rate of agitation alongside both the excess of carbon and limitation of nitrogen need to be considered in the selection of microbial strains for PHB production (Saharan et al. 2014).

Statement of Problem
Synthetic plastics is not easily degraded from the environment thereby leading to environment pollution and when these synthetic plastics is burnt, it releases toxic volatile organic carbon into the environment their by contributing to indoor and outdoor air pollution which result in several spectrum of human diseases.

Justification of the Study
This study “The effect of nitrogen sources in the production of polyhydroxybutyrate from micro-organisms isolated from an engine oil contaminated soil” will be of immense benefits to the societies, it will help the health sector in the eradication of health problems associated with the synthetic plastics. It will also add to the existing stock of knowledge in the area of the study. This study will go a long way to provide information to individual, private and public sector on the subject and it will serve as a reference material to students who may embark upon further research work.

Aim and Objectives

1.4.1 Aim of the Study
The aim of this study is to screen and characterize bacteria capable of producing polyhydroxybutyrate from an Engine oil contaminated soil.
1.4.2 Objectives of the study
The objective of the study includes the following;
Isolation and identification of bacteria isolated from an engine oil contaminated soil
Screening of bacteria isolate for polyhydroxybutyrate production.
Production and quantification of polyhydroxybutyrate.
To study the effect of nitrogen sources on polyhydroxybutyrate production by the bacteria isolate.