Civil Engineering 1 ppt Semina Presentation by 282REF

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									PRESENTER: IP MOLOBELA
MAY 10 ,2011
Microbial biofilms and their
impact in the water industry
     College of Science, Engineering and
                   Technology
Civil and Chemical Engineering Department
          University of South Africa
                Objectives
 To introduce you to the concept of biofilms
 To let you know why the study of biofilms is
  important in the water industry
 To help you see how biofilms are radically
  changing the way we understand and deal
  with them as they change
 To excite you about the prospects of the
  continued study of biofilms and the
  technologies on biofilm control and removal
                Outline
 Biofilms What are biofilms?
 What are the parameters contributing to
  their formation and development?
 Why is it important to study biofilms in
  the water industry – is it really
  necessary?
 What are the disadvantages of chemical,
  physical and mechanical strategies in
  controlling but most importantly
  removing microbial biofilm?
 Are the above mentioned strategies
  successful in removing microbial
  biofilms? The answer is “............”
 “Enzyme Technology”- An emerged
  technology for microbial biofilm control
  and removal. Is this technology effective?
  The answer is “..........”
                   What are biofilms?
 Prof Flemming                         simply defines biofilms
  city of microbes; EPS houseof microbes
 Group of microorganisms (bacteria, fungi
  etc) (attached to biotic or abiotic surfaces immersed in an aqueous environment)
 Embedded in extracellular polymeric
  substances (EPS).
 Biofilms have complex social structures
  that scientists and engineers are still
  trying to unravel
Cont
 EPS is made up of carbohydrates, proteins,
  amino acid, lipids including humic
  substances
 Biofilms produce different EPS structures
  (depending on growth conditions)
   What is the role of EPS during
       biofilm formation?
 Facilitates attachment (protects biofilm
  cells)
 Maintains micro colonies (structural
  integrity)
 Protects the biofilm cells from harsh
  conditions and predation
 Enables the biofilms to capture nutrients
  (surrounding fluid medium)
 Enhances     biofilm      resistance    to
  environmental     stress,     antimicrobial
  agents (bactericidal, fungicidal etc)
                                                              EPS structures




Pseudomonas fluorescens biofilms (Picture, Molobela IP, PhD
studies )
                                                             threat like structures
                                                                          EPS




Pseudomonas fluorescens and Staphylococcus lentus biofilms
(Pictures, www.informaworld.com)
    Biofilm developmental cycle
              (stages)
 Attachment (Protein molecules, flagella,
  fimbria etc) (conditioned surface)
  Primary stage (reversible)
  Secondary stage (irreversible)
 Formation of micro colonies
 Biofilm maturation
 Detachment and dispersal of biofilm cells
Picture of Liang Research group (LL)
 What are parameters influencing
biofilm attachment and formation?
 Nutrients
 Temperature effects
 Surface condition
 Hydrodynamics
 Quorum sensing (QS) (Gene expression
  and regulation)
   Why is it important to study
  biofilms in the water industry?
 They are the mainly reason water
  infrastructures and pipe materials are
  corroded (causative agent of biofouling
  and biocorrosion
 Corrosion is the mainly problem in the
  water industry
 Biofilms are also the biological
  contaminants of drinking water
   Developed methods for biofilm
        control and removal
1. Chemical         method     (Bactericidal,
    Fungicidal, antimicrobials etc)
Disadvantages
 Partially effective
 Fails to penetrate the EPS
 Cannot destroy the biofilm cells
 Some toxic to the surface materials
 Environmental      unfriendly    (produce
  odour) (their use-regulated by the EPA)
2. Mechanical method (machines for
   cleaning)
Disadvantages
 Cannot       penetrate      to     biofilm
  contaminated sites/ areas
 Costly - involves equipments down site
          - also labour expenditure
  Enzyme Technology for microbial
         biofilm removal
 Effective and robusting
Enzymes are specific
     - target specific components
Therefore: Enzyme can also target biofilm
  EPS (EPS - proteins, carbohydrates, lipid,
  amino acid)
Note: It is important to understand the nature of EPS so
  that relevant enzymes are used
Enzymatic degradation of biofilm EPS
 (Molobela et al., 2010)

                            Proteases (Savinase, Evelase, Esperase, polarzyme )

               Tested enzymes                           Tested biofilms
        Individually Combination                 Single    multi species


            Mechanism of removal -
               Degradation of EPS           Individually       Combination
         single        multi species

        Savinase >80%       >80%            Single Species        multi species
        Evelase >80%        >80%           Highly effective    Highly effective
        Esperase >80%       >80%
        Combination >90%    >80
    Amylases (Amyloglucosidase (AMG), Bacterial Amylase Novo (BAN)

        Tested enzymes                          Tested biofilms
Individually Combination                 Single    multi species



   Mechanism of removal -            Individually           Combination
      Degradation of EPS
single         multi species
AMG >50%           >50%              Single Species          multi species
BAN <50%           <40%              Partially effective    Not effective
Combination >50%   >50%
Combination of protease and amylase enzymes

        Tested biofilms              Combination
 Single    multi species
                            Single Species      multi species
                             Highly effective     effective


   Mechanism of removal -
      Degradation of EPS
single      multi species
>80%        <80%
Methods used to study biofilm EPS
   Protein assay- Froelund et al., 1996
   Carbohydrate assay - Gaudy’s, 1962
   Biofilm growth Assay – Molobela et al., 2010
   Enzymatic degradation of biofilm EPS –
    Molobela et al., 2010
              Conclusion
 Study the nature of the biofilm EPS
 Study the type of microbes within a
  biofilm
 Thorough study on the impcat of
  parameters influencing biofilm formation
  and structures
Cont
 Design of models for monitoring of
  biofilm attachment, formation and
  development and study the structures of
  biofilm EPS
 Enzymatic technology seems promising
  on biofilm removal. However, more
  research still need to be done on this
  study
 Collaborative research on biofilm study
  (involvement of expertise – different
  disciplines
         Note to take home!
 We have talked about biofilms being bad!
  Yes many of them are quite harmful and
  must be controlled and most importantly
  removed.
 However Other biofilms are beneficial,
  and can be used to help fix serious
  problems (such as ground contamination
  from an oil spill, bioremediation,
  nitrogen fixers, rhizobial biofilms etc)
I thank you!!!!!!!!!
I am a strong biofilm, I destroy and destroy and destroy!!!!!!!!
 Hahahahahaha!!!!!!!!!!!!!!!!!!!

								
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