ABSTRACT
The study was carried out to isolate and identify microorganisms that cause deterioration of construction wood within Michael Okpara University of Agriculture. Five (5) different samples of deteriorated woods were collected from different locations of buildings within the Michael Okpara University of Agriculture buildings namely Male Hostel, Engine Workshop, COLNAS Extension, Computer Village and MOUAU Poultry. The debris of wood were scrapped out from wood aseptically using a sharp sterilized pen knife into a clean container and covered immediately to avoid contamination with foreign materials. The samples were processed aseptically using the serial dilution technique and appropriate dilutions inoculated onto nutrient agar, Mannitol Salt agar, Sabourand Dextose agar and MacConkey agar plates while total viable heterotrophic aerobic counts were determined using pour plate technique. Staining technique for identification of fungi while the bacteria isolates were then identified following standard microbiological procedure. Result obtained reviewed that the fungi isolated from samples from different locations include Aspergillus flavus, Apergillus fumugatus, Apergillus niger, Rhizopus stolonifer . Their perecentage occurrence was Apergillus flavus (80%), Aspergillus fumugatus (80%) and Aspergillus niger had the highest percentage occurrence which was (100%), and the least was Rhizopus stolonifer which has (20%). These fungi are spore formers and therefore can survive unfavourable conditions than the non-spore forming bacteria. The presence of Staphylococcus aureus (60%), Escherichia coli (80%), Klebsiella spp.(40%) and Serritia spp (20%). The occurrence rate indicated the possibility of contamination of wood. The study recommended that constant fumigation is necessary especially Male hostel and Computer village to decrease the activities of these microorganisms, paint should be applied on wood surfaces to prevent decay by protecting wood from intermittent wetting, especially if applied to ends and edges as well as to exposed faces, degradation of waste materials especially wood by cellulose producing microorganisms should be exploited for industrial and commercial purpose among others.
TABLE OF CONTENTS
Title page i
Certification ii
Dedication iii
Acknowledgements iv
Table of Contents v
List of Tables vii
List of figures viii
Abstract ix
CHAPTER ONE
INTRODUCTION 1
1.1 Aim
of research 2
1.2 Hypothesis 2
CHAPTER TWO
LITERATURE REVIEW
2.1 Wood 3
2.2 Structural and chemical features of wood 4
2.3 Degradation
of wood by fungi 5
2.3.1 White Rot Fungi 6
2.3.2
Brown Rot Fungi 6
2.3.3
Soft Rot Fungi 7
2.4 Bacterial degradation 8
2.5
Decay resistance of wood 9
2.6 Cellulose 10
2.6.1 Application of Cellulose 13
CHAPTER THREE
MATERIALS AND METHODS
3.1 Study
area 15
3.2 Sample collection 15
3.3
Sterilization of materials 15
3.4 Normal saline preparation 16
3.5 Media preparation 16
3.6 Serial dilution 16
3.7
Enumeration of total heterotrophic bacteria and fungi 16
3.8 Fungi
identifications 17
3.9 Bacteria
identification 17
3.10 Gram
staining 18
3.11
Biochemical test 18
3.11.1 Catalase
test 18
3.11.2 Coagulase test 19
3.11.3 Indole
test 19
3.11.4 Motility
test 19
CHAPTER FOUR
RESULTS 20
CHAPTER FIVE
DISCUSSION, CONCLUSION AND RECOMMENDATION 26
5.1 Discussion 26
5.2 Conclusion 28
5.3 Recommendation 28
REFERENCES
APPENDIX
LIST OF
TABLES
Table Title Page
2.1: Composition of wood 4
1: Variable
microbial count from deteriorating wood in MOUAU
(cfu/g) 21
2: Identification of
Bacterial isolates from deteriorating Wood in
MOUAU 22
3: Identification of fungal isolated from
deteriorating wood in MOUAU 23
4: Percentage occurrence of isolates from
deteriorating wood in MOUAU 24
5: Distribution of microbial isolates from
deteriorating wood and their
percentage 25
LIST OF FIGURES
Figure Title Page
1: Lignocellulose
degradation by basidiomycetous fungi 12
CHAPTER ONE
INTRODUCTION
Wood is made up of
cellulose and lignin. Lignin makes up of about a third of the mass of typical
wood and also adds great strength to the wood (Anderson et al., 2007). Our society depends on wood
for a variety of uses. Wood is by far, the most versatile and beautiful
building material available to man. It has been with us since man first started
to build his own shelter (Wong, 2007). Cellulose fibrils have high tensile
strength which is used in the textile industry, paper and miscellaneous
materials like vulcanized fiber, plastic filters, filtering media and surgical
cotton. Other uses include adhesives, explosives, thickening agents, coated
paper, cellophane, artificial leather, films and foils (Hitchner and
Leatherwood, 1982). And yet, it is also the only building material that is
subject to destruction by biological agencies, such as fungi and insects. This
is one of the inherent disadvantages of using wood as a building material. Wood
is actually a very inert material, i.e., it does not go into chemical reactions
that will actually destroy the material. It is surprisingly immune to acids,
alkalis and. strong detergents (Wong, 2007).
As population
increases, so does our need for wood especially with modern use of timber in
construction of less costly buildings in order to make houses available to the
increasing population. Steel, concrete and aluminium are some alternatives to
treated wood in certain applications, but they have higher material costs,
higher energy requirements in the production process, greater air and water
pollution or environmental protection costs, and greater dependency on foreign
sources for materials, Substitute materials may not be appropriate for some
uses. For example, some types of steel may corrode; concrete may deteriorate in
salt water renewable natural resource that, if properly treated, maintained and
placed in service, will last indefinitely. It is critical for us to use our
wood resource efficiently.
This research is
intended to increase our knowledge of the causes and control of wood decay and
degradation. A common cause for replacing wood structures is decay or
degradation. More recently however, there have been changes in the structure of
the forestry sector. The forest resource survey. 1996-1998, revealed that the
forest cover has decreased by 20% over the preceding 18 years. According to Adeyoju (2001), the total
forest estate which stood at 10% of the country's land area in 1996 is now less
that 6%. Ola Adams and Lyamabo (1977) estimated that about 26,000 ha of forest
land are destroyed annually in the rainforest zone during the conversion of
natural forests to plantation forests and other forms of land use. World
Wildlife Fund estimated that over 90% of the natural vegetation had been
cleared and over 350,000 ha of forest and natural vegetation are lost annually
(WWF, 1989). Wood decay problems can be prevented for years by properly using
and protecting wood. The heartwood of some species has a unique chemical
composition that makes it very durable.
1.1 AIM AND OBJECTIVES
Aim:
To isolate and
identify microorganisms from deteriorating construction wood materials
Objectives:
i)
To
isolate and identify microorganisms from deteriorating wood
ii)
To
determine the percentage occurrence of these isolates
iii)
To
determine the distribution of these isolates
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