Biodeterioration 
"Biodeterioration" and "bioremediation" are the two 
aspects of biodegradation with an anthropomorphic 
emphasis. Biodeterioration is the breakdown of 
economically useful substances often the term is used 
narrowly to refer to the deterioration of substances that 
are normally resistant to biological attack such as metals, 
plastics, drugs, cosmetics, paintings, sculpture, wood 
products, electrical equipment, fuels and oils, and other 
objects (Sarkar et al.,1997). In bioremediation, biological 
systems are used to transform and/or degrade toxic 
compounds or otherwise render them harmless. 
Bioremediation can involve indigenous microbial 
populations with or without nutrient supplementation, or it 
can involve inoculation of exogenous organisms into the 
site. When exogenous organisms are added, the process 
is called "bioaugmentation." In either Case, the goal is to 
disharm noxious chemicals without the formation of new 
toxins. Micro-organisms have a simple approach to life; 
they use whatever is available as a food source, attach 
themselves to practically all surfaces, multiply and build 
up biomass. Everyone is familiar with the phenomenon of 
rotting, the natural decay and recycling of materials by a 
wide range of life forms, including micro-organisms. This 
process is termed as biodegradation and it is perceived 
as a beneficial or positive process. Biodeterioration may 
be defined as ‘the deterioration of materials of economic
importance by micro-organisms’; it is perceived as a 
deleterious or negative process. Biodeterioration has 
been classified as follows: Mechanical biodeterioration, 
Chemical assimilatory biodeterioration and soiling. 
Mechanical biodeterioration 
This occurs when the material is damaged as a direct 
result of the physical activity of an organism, such as its 
movement or growth. An example of this kind of 
biodeterioration is the damage caused to electrical 
cabling as a result of insect or rodent attack. 
Chemical assimilatory biodeterioration 
This is perhaps the most common form of 
biodeterioration. It occurs when a material is degraded for 
its nutritional value. For example breakdown of cellulosic 
materials such as wallpaper by cellulolytic fungi is an 
example. 
Chemical dissimilatory biodeterioration 
This occurs when a material is damaged as a result of 
the production and release of metabolic products by 
microbial activity that may corrode pigment or toxify the 
material. The poisoning of grain by mycotoxins and the 
release of pigments into plastic films are examples of this 
process.
Soiling 
This visible form of biodeterioration occurs when the 
mere presence of an organism or its excrement, renders 
the product unacceptable. The function of the material 
may be impaired by the presence of the organisms, as in 
the fouling of ships’ hulls by barnacles and algae. It is 
essential to appreciate that more than one of these 
biodeterioration processes, or indeed all of them may be 
occurring at the same time. Materials of economic 
importance known to be subjected to biodeterioration 
include: stored agricultural products, archival material 
products, pulp paper, wood and allied textiles and leather, 
constructional materials, fuels and lubricants, 
pharmaceuticals, metals cosmetics, paints, polymers, 
rubbers and stone, buildings, glass, adhesives and 
sealants. The list is extensive and it includes most of the 
industrial materials that readily come to mind. It is difficult 
to accept that some of these materials (glass, metal, 
stone) are susceptible to microbial attack. 
Biodeterioration of emulsion paints 
Only water-based-paints are susceptible to 
biodeterioration during their manufacture which may give 
rise to in-can problems. Thinning of the paint results when 
the thickener, usually cellulose ether, is attacked by 
cellulase enzymes produced by bacteria and fungi 
introduced into the formulation via contaminated 
components. Talc, which is used as an extender in paint 
formulation, has been cited as a possible source of 
contamination