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Development and CharacterizationChitosan blended Bacterial celluloseFilm
Proposed by Mr.Kampole Intasorn 5470120921Thesis Advisor :Associate Professor Muenduen Phisalaphong, Ph.D.
Chulalongkorn University
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Contents1
2
Introduction
Theory and principles
Objectives and research scope
Material and Methods
Result and discussion
5 Conclusion
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3
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4
5
6
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IntroductionPlastic waste problem
Shalleh et al.,2007
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IntroductionFood packaging
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Introductionplastic waste
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IntroductionTo solution the problem
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Theory and principles
Chitosan
Figure 1 Structures of cellulose, chitin and CH (Muzzarelliry .,1973).
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Theory and principles
Chitosan
Figure 2 preparation of chitosan from chitin (Muzzarelli., 1977).
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Theory and principlesAntimicrobial of Chitosan
Figure 3 Antimicrobial of chitosan (Chen et al,1998)
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Theory and principles
Bacterial cellulose(BC)
Figure 4 Structure of Cellulose (Nishiyama et al .,2002).
Figure 5 Bacterial Cellulose (
http://agsci.psu.edu/magazine/articles/2010/winter-spring/building-a-better-bandage
)
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Theory and principles
Bacterial cellulose(BC)
Figure6 SEM micrograph of structure Bacterial Cellulose (Phisalaphon,et al., 2007)
Figure7 Size of synthetic and naturally occurring fiber
(Yoshinaga et al, 1997).
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Objective
1.To develop chitosan/BC composite film (CBC) 2.Characterize for its mechanical and antimicrobial properties.
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Research scope
Chitosan/BC (CBC) composite films are fabricated by casting method at room temperature (30°C±5°C).
Characterization of CBC is as follows:
Mechanical property
Antimicrobial property
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Material and Methods
Material 1. Chitosan ;Seafresh Chitosan Powder 85% DAC and Molecular weight 200,000.2. Bacterial Cellulose (BC); The A. xylinum strain was isolated from nata de coco.
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Material and Methods
Figure8 Chitosan powder Figure9 nata de coco.
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Material and Methods
Preparation of Chitosan solution
Chitosan (1%, w/v) was mixed in acetic acid solution (1% v/v)pH was adjusted to 5 with 1N NaOH
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Material and Methods
Preparation of BC slurry
Washed by DI waterAnd Spun
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Material and Methods
Blending
Then mixed with BC slurry at various weight ratio (Chitosan:BC) 10:2 to10:10.
Moreover, Glycerol (2%v/v) was used to be the plasticizer for these mixture
Stirred overnight
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Material and Methods
After the solution was homogenous mixture, poured into Petri plate and dry with incubator at 35 °C for 5 days.
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Material and Methods
Figure 10 Product
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Result and discussionFig11. Tensile strength(MPa)
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Result and discussionFig12. Elongation at break(%)
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Result and discussionFig 13. %Water adsorption capacity
Result and discussionTable 1: Antimicrobial activities of CBC films against
E. coli and S. aureusMicro-
organismSample The Number
of bacterial%
reduction
E. coli
Controla 3.8 x 105 -
ChitosanMw.200,000
3.5 x 105 7.89a
Controlb 2.2 x 105 -
Chitosan:BC10:6
6.5 x 105 0b
S. aureus
Controlc 4.2 x 105 -Chitosan
Mw.200,0002.9 x 105 30.95c
Controld 3.2 x 105 -
Chitosan:BC10:6
2.0 x 105 37.50d
a-d refer to different control inoculums.
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ConclusionThe mechanical properties of the CBC films depended on the weight ratio of BC.
The water absorption capacity of the film was maximal at 548.2% obtained from the composite film with the ratio of chitosan : BC at 10:6.
The CBC films were able to significantly inhibit S. aureus growth .
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Thank you for your attention
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Why do you use Chitosan Mw.200,000?
To compare 3 Mw.30,000 80,000 and 200,000
The results showed that mw.200,000 is The most appropriate in term of strength.
Jeremy L. Chen and Yanyun Zhao Reported that tensile strength of high mwChitosan films higher than that of low mw
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How to calculate % reduction?
C-AReduction,%(CFU/mL)= ×100
CWhere A = CFU/mL for the flask containing the treated substrate after the specified contact time.C = CFU/mL for the flask containing the untreated substrate after the specified contact time.(Control)
Ex chitosan film inhibits E.coli 5 5
5
3.8x10 -3.5x10%Reduction= ×100=7.89
3.8 10a
x
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What is %DAC mean?
The term “degree of deacetylation”is used to representthe amount of N-glucosamine units in molecules. If the degree of deacetylation is higher than 50%,it will be classified as chitosan.In contrast, when the deacetylationis lower than 50%, the term chitin is used (Krajewska, 2004).
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Why CBC films can’t inhibit E.coli growth?
Composition Gram positive. Gram negative.
Peptidoglycan. 60-100%. 5-20%.
Amount of lipid. 0.2%. 10-20%.
Polysaccharide. 35-60%. 15-20%.
Cell wall 1 2
The cell wall of gram-negative and gram-positive bacteria have a different key for this
Ref:http://www.medtechzone.com/data/bac/bacteria.php, Andrew P. Desbois & Valerie J. Smith, Appl Microbiol Biotechnol (2010) 85:1629–1642Lian-Ying Zheng*, Jiang-Feng Zhu Carbohydrate Polymers 54 (2003) 527–530
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Why the number of bacterial more than control ?
CBC cannot able to inhibit the growth of bacteria,So bacteria can growth on CBC film.
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Why CBC films inhibit S.aureus more than pure Chitosan
film?
The value of the test is not very different. So we can not conclude that the BC supplementcan increase the S.aureus inhibition.We try to experiment more.
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