A biofilm is a complex
microorganisms growing on
a solid surface, i.e. in a bed
of polymer material which
they themselves have made.
Biofilms may be found on
environmental surface in
which sufficient moisture is
A Biofilm Primer
Biofilm primer is composed of
populations or communities of
microorganisms adhering to the
These microorganisms are
usually encased in an
extracellular polysaccharide that
they themselves synthesize and
thus forming communities.
Their development is most rapid
in flowing systems where
adequate nutrients are available.
Where biofilms are found?
Typical locations for biofilms production include
2.Surfaces in marine or fresh water environment.
Biofilms associated with living organisms.
These communities are composed of a range of different
types of organisms, both autotrophic and heterotrophic.
Tissue surfaces such as teeth and intestinal mucosa
develop a complex aggregation of microorganisms and thus
• This figure is of Human
dental plague.It shows
ability of oral bacteria to
store iodophilic polysaccharides or glycogenlike molecules inside their
cells. This prolonged
exposure leads to
decalcification of tooth
• Microbial Mats are
mainly of photosynthetic
prokaryotes. This microbial
mat in a roadside puddle
formed quickly during
Formation of biofilms
Biofilms tend to form wherever a surface on which bacteria
Biofilm forms when bacteria adhere to surface in aqueous
environment and begin to excrete slimy, glue like substance
that can anchor them to all kinds of material.
Biofilm forms:a)On solid substrate in contact with moisture.
b)On soft tissue surface in living organisms.
c)At liquid air interface.
Structure of Biofilms
Biofilm structures take a wide
variety of forms depending on
their age and growing conditions.
This structural complexity allows
bacteria deep within the biofilm to
have access to nutrients carried
by the convective flow of water.
The BAP protein (Biofilm
associated protein) which
presents a structural organization
similar to other surface proteins
in a number of species of
Antibiotic Resistance of biofilms
Bacteria in biofilms are extremely resistant to antibiotics.
During the development of a chronic infection the bacteria
form community structures known as biofilms that are like
cities of bacteria.
Living in groups gives the bacteria properties that they do
not have as individuals.
They are also impervious to the body's natural immune
Biofilm infections are a major medical problem.
Anti-biofilm defense mechanism
of human body.
Lactoferrin is a component of the body's antibacterial
Bacteria when grown in the presence of small amounts of
lactoferrin were unable to develop into biofilms.
As a consequence, these bacteria remained vulnerable to
antibiotics and other antimicrobial substances.
Lactoferrin causes bacteria to roam across a surface.
Anti-biofilm defense mechanism of
Lactoferrin traps iron, making it unavailable to the bacteria.
Iron is a critical nutrient for bacteria and is difficult to acquire
from the environment.
When they sense iron levels are low, the bacteria keep
moving rather than establishing complex communities in an
area where a critical nutrient is in short supply.
Genetic changes prevent antibiotic
resistance of biofilms
Biofilms highly resistant to antibiotics.
A subset of genes in a bacterium behave
Mutations in biofilm genes cause changes in
biofilm growth and maintenance.
Proteins are important targets aimed at treating
A water treatment reactor ie a
bioreactor was devised that
serves as a minibiological
purification plant for servicing
a single home or a
The efficient design of the
bioreactor reduces the size
and the expense of a water
treatment plant and also
makes it amenable for the
recirculated water used for
Working of bioreactor
The bioreactor contains a series of plastic hollow particlelike carriers on which a biofilm grows rapidly. The biofilm
causes contaminants to decompose.
On its outer surfaces, the biofilm is abraded as the plastic
particles rub against each other due to the flow in the
The abrasive action of the intense, heavy rubbing of the
carriers causes contaminants to decompose.
The bioreactor continuously removes dead microorganisms
from the exposed surfaces, and the microfilm carriers are
always appearing with a new active biofilm.
Biofouling or biological fouling is the undesirable
accumulation of microorganisms, plants, algae, and animals
on submerged structures, especially ships' hulls.
Biofouling also occurs
1.On the surfaces of living marine organisms.
2.In membrane systems such as membrane bioreactors.
3.As fouling in cooling water cycles of large industrial
equipments and power stations.
4.In groundwater wells
5.In the exterior and interior of ocean-laying pipes.
Fouling causes huge material and economic costs in
maintenance of mariculture, shipping industries, naval
vessels, and seawater pipelines.
Biofouling is divided into
1)microfouling - biofilm formation and bacterial adhesion
2) macrofouling -attachment of larger organisms.
In order to minimize the impacts of foulers, many
underwater structures are protected by antifouling coatings.
Coatings, however, have been found to be toxic to marine
Anti-fouling is the process of removing the accumulation, or
preventing its accumulation.
In the latter case it has been shown to retard the seawater
flow through the pipe and has to be removed with the tube
Whether it's the disgusting
yellow film coating your teeth
or the slippery crud clogging
your kitchen sink, slime is
something most of us want to
eliminate and not cultivate.
Biofilm impact can be seen
in the neighbouring figure:
Threats of Biofilms
Biofilms can be a serious threat to health especially in
patients in whom artificial substrates have been introduced.
These recurrent infections are due to the accumulation of
mixed biofilms on the artificial surfaces provided by the
catheter or other implant.
In vitro experiments suggest that bacteria encased in
biofilms may be 50 to 500 times more resistant to
chemotherapy than planktonic bacteria of the same strain.
Fragments of biofim that slough off at intervals can spread
the infection to distant locations within the body.
Most common destruction caused
Microbial Ecology of Biofilms in Beef Processing
Oral Bacteria May Predict Pregnancy Outcomes
Periodontal disease ie- periodontitis caused by
Biofilms Inside Bladder Cells May Cause
Recurrent Urinary Tract Infections
Destructions by biofilms continued..
Biofilms in Urinary and Foley Catheter.
Bacterial Biofilms Biofilms, source of Recurrent
Chronic Middle Ear Infections Linked To
Resistant Biofilm Bacteria.
Lungs of cystic fibrosis are infected with
Destruction by biofilms continued..
Mechanical Heart Valve Biofilms.
Cholera Bacteria Focuses on Biofilm Formation.
Microbial biofilms in food industry.
Biofilm formation in ship’s hulls.
Benefits of Biofilms
Humans have made considerable use of microbial
biofilms, primarily in the area of habitat remediation.
1.Water treatment plants
2.Septic systems associated with private homes remove
pathogens and reduce the amount of organic matter in the
3.Biofilms Removes Drinking Water Contaminants ie waste
water treatment plants.
4.Snottites, Other Biofilms Hasten Cave Formation
Viruses are Build to Combat Harmful Biofilms with the
help of metagenomic technique.
Effectiveness of ozone, heat and chlorine for destroying
common food spoilage bacteria in synthetic media and
Preventing Biofilms Could Help Fight TB
Raisins Fight Oral Bacteria.
Preventive measures continued..
Herbal Treatment for Recurring Urinary Tract Infections
UV Light, Coatings Reduce Bacterial Adhesion up to 50
Monochloramine Treatment Not as Effective in Protecting
Biofilm-Science and Technology by Luis.F.Melo
Industrial Biofouling detection, Prevention and control by Janes
Walker Susanne Surman Jana Jass.
Trinet, F; Heim, R; Amar, D; Chang, HT; Rittmann, BE
Water Science & Technology. Vol. 23, no. 7-9, pp. 1347-1354.
International journal of food Microbiology Volume 42, Issue1
Textbook of biotechnology “Control of pollution”(biological
method of biofilteration)Das.H.K.2004 pg no 11155-1159 2nd
Industrial biotechnology –Problems and Remedies by Indu
Shekhar Thakur pg no 44-68.
Biotechnology A to Z, edition3 by William Bains.
Sailing World article.