Thesis Abstract

Abstract
Micrococcus species are widely distributed in nature and have been found in various environments, including fermented foods. In this study, we aimed to isolate and characterize Micrococcus species from fermented ugba, a Nigerian traditional food product made from fermented oil bean seeds. Samples of ugba were collected from different local markets in Nigeria and processed in the laboratory for the isolation of Micrococcus species. Several selective and differential media were used to isolate and identify Micrococcus colonies based on their morphology, biochemical characteristics, and molecular techniques. The isolated strains were further characterized using biochemical tests, including catalase and oxidase tests. Molecular identification was performed by amplifying the 16S rRNA gene and sequencing the PCR products. The results revealed the presence of Micrococcus species in the fermented ugba samples. The isolated strains showed typical characteristics of Micrococcus, such as spherical cells arranged in tetrads or clusters. Biochemical tests confirmed the identity of the isolates as Micrococcus species, showing positive catalase and oxidase activities. Furthermore, molecular identification based on 16S rRNA gene sequencing confirmed the presence of Micrococcus luteus in the ugba samples. Phylogenetic analysis showed a close relationship between the isolated strains and known Micrococcus species, supporting their identification as members of the genus Micrococcus. The isolation of Micrococcus species from fermented ugba highlights the potential role of these bacteria in the fermentation process of ugba. Micrococcus species are known for their ability to produce various enzymes and metabolites that contribute to the flavor and aroma of fermented foods. Understanding the diversity and characteristics of Micrococcus species in ugba could provide insights into the fermentation dynamics and quality of this traditional food product. Overall, this study contributes to the knowledge of the microbial diversity in fermented foods and sheds light on the importance of Micrococcus species in the fermentation of ugba. Further research is needed to explore the functional properties of these isolated strains and their potential applications in food fermentation and biotechnology.

Thesis Overview

1.0   INTRODUCTION

Ugba also called ukpaka is a popular food delicacy in Nigeria especially among Ibo ethnic group. It is rich in protein and is obtained by a solid state fermentation of the seed of African oil bean tree (Pentaclethra macrophylla Benth). It is essential food item from various traditional ceremonies where it is mixed with slices of boiled stock fish (ugba and okpoloko). The natural fermentation of the seed which at present is still done at the house-hold level, renders the production nutritious, palatable and non-toxic (Enujiugha, 2002).

Its production, like many African fermented foods depends, entirely on mixed fermentation by microorganism from diverse source.

Some of these seeds have been exploited as soup bases such as Gbegiri from Vigna unguicuata (Akanbi, 1992). Others are fermented and used as condiments and seasonings such as okpei from Prosopis africana (Achi, 1992) and ogiri from Ricinus cummunis (Odunka, 1989). Another of such seeds is the African oil bean seed (Pentaclethra macrophylla Benth), a highly nutritious leguminous crop seed abundant in the rain forest areas of west and central Africa.

Pentaclethra macrophylla Benth is a large woody plant abundant in the rain forest areas of west and central Africa. It’s origin in Nigeria is believed to be around 1937 (Ladipo, 1984); where it is found in the South Nigeria, (Mbajunwa et al, 1998).

“Ugba” Pentaclethra macrophylla Benth belongs to the Family Leguminosae and sub-family microsoideae (Keay, 1989 and NFTA, 1995).

Ugba seeds are irregular and oval, they are flat, black and hard pods. It is composed of oil, protein and small amounts of carbohydrate (Obeta, 1982).

Production of Ugba is still on age old traditional family in the rural area. The fermentation depends on random inoculation of boiled slices of the oil bean seed by microorganism within he immediate environment. Earlier report attribute the sources of the micro-organism to the leaves used in packaging, human handling, container and utensils used in processing (Obeta, 1993, Odunfa & Oyeyiola, 1985).

A number of researches have been carried out to know what causes this fermentation, and was attributed to micro-organisms that are probably introduced through the air, water, and banana leaves. Organisms such as Micrococus roseus, Micrococcus luteus, Leuconostoc mesenteroides, Staphylococcus aureus, Staphylococcus epidermidis, Bacillus substilis, Bacillus megaterium and Bacillus circclans, E-Coli

Fermented African oil bean seed (ugba), has a high rate of susceptibility to microbial spoilage and therefore has a very short self life of 1-2 weeks (Enujiugha & Olajundoye, 2001).

Manifestation of food spoilage are many and vary typically resulting in an off smell, colour, taste and texture.

Reports by Mbajunwa (1998) Obeta, (1983) and Nwagu et al. (2010) indicates that micrococcus species do not play an active role during microbial fermentation of Ugba.

However, further work on spoilage association of ugba by Nwagu et al (2010) showed that the population of Micrococcus sp increased with increase in keeping time of ugba. This indicates the ability of micrococcus to thrive in the alkalophilic environment while constituting as a spoilage organism of ugba. This may be attributed to the ability of microorganism to produce amylase, lipase, or protease able to utilize protein, carbohydrate or lipid content of ugba as source of nutrition (Njoku et al., 1990).

Amylases are enzymes that breakdown starch or glycogen. The amylases can be derived from several sources such as plants, animals and microbes. The major advantage of using microorganisms for production of amylase is in economical bulk production capacity and microbes are also easy to manipulate to obtain enzymes of desired characteristics

1.1   Aims and Objectives

This work is aimed at the following;

a.           isolating micrococcus from fermented ugba

b.           producing amylase from the micrococcus from ugba