14 Bioplasticx - Murdoch University

shamebagBiotechnology

Feb 22, 2013 (4 years and 6 months ago)

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BIOPLASTIC PRODUCTION:

BY HASMITA RAMJI PATEL STUDENT ID: 31208401

contact:hasmita912@gmail.com

Image obtained from pakbec.blogspot.com

1

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list


Author profile


My name is Hasmita patel and I am pursuing a double major in B. Sc
biotechnology/Biomedical Science at
M
urdoch University in Perth, Western
Australia.



Being a biotechnology student, I strongly feel there is a need to apply the
scientific knowledge that I have gained from my degree in regards to issues
that need urgent attention for example global warming.



Therefore, I thought doing article summaries on

bioplastics

would be good
topic to do so that any one who reads this gets an idea of how important it is
to protect the environment and how easy it could be to actively start doing it
as well.

2

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list


Papers used for comparisons

Summary paper 1:

Conversion of industrial food wastes into bioplastics

P, H. Yu, H. Chua, L. Huang
A,
W. Lo,
and Q. Chen G. 1998. "Conversion of Food
Industrial Wastes into Bioplastics."
Applied Biochemistry and Biotechnology

70
-
72
(1): 603
-
14. doi:http://dx.doi.org/10.1007/BF02920172
.


Summary paper 2:

Poly
-
β
-
hydroxybutyrate production by fast growing rhizobia cultivated in sludge
and in industrial wastewater

Rebah,F.B., Prevost, D., Tyage, D.R. and Belbahri, L. “
Poly
-
β
-
hydroxybutyrate
production by fast growing rhizobia cultivated in sludge and in industrial
wastewater” (2008).
Applied Biochemistry and biotechnology
. 158: 155
-
163. DOI
10.1007/S12010
-
00808358
-
1


3

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list


Executive summary:



L
arge amounts of waste are discarded from industrial based industries that in turn
harms the environment leading to global warming.



These two summary papers demonstrate how industrial wastes from a beer brewery (
summary 1) and sludge industrial waste (summary 2) could be used to produce
bioplastics using
Alcaligenes eutrophus

and fast growing Rhizobia respectively.

These
are both bacteria that are capable of producing PHAs.



Summary paper 1 was able to demonstrate that using different carbon sources as
food for the bacteria can lead to different types of PHAs being produced.



From summary paper 2 it was proved that the different Rhizobia that were found in
the wastewater could be used to make PHAs thus providing an environmentally
friendly way to use the wastewater that could otherwise be disposed off and cause
harm to the environment.

4

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list


INTRODUCTION

o
Rapid growth of the human population has led to the amount of non
biodegradable waste pollution in recent years


o
There is an urgent need to create biomaterials that are biodegradable and can
Biomaterials are natural products that are synthesized and catabolised
by different
organisms and that have found broad biotechnological
applications. (Kumaravel,
Hema & Lakshmi,2010 )


o
In addition there also is the likelyhood that the fossil fuel reserves that are used to
make plastics will drastically reduce in the coming
years (
Kumaravel
,
Hema

&
Lakshmi,2010 )



o
Thus there is a need to create biodegradable materials that can be both
biodegraded and recycled.


o
Biomaterials are natural products that are synthesised
and catabolised
by different
organisms and that have
found broad
biotechnological applications. They can be
assimilated by
many species (biodegradable) and do not
cause toxic
effects in the
host (biocompatible
)

produced by a range of microbes,
cultured under
different
nutrient and environmental
conditions (Luengo et al., 2003).


o

They are lipid
in
nature and are
accumulated as storage materials

allowing
microbes to survive
under stress (Luengo et al., 2003)
.


o
However the main
limitations for the bulk
production of
bioplastics are its high
production and recovery costs (Luengo et al., 2003)
.


o
40 to 50% of the total
production cost
is related to the raw
material.
In order to
reduce the production cost, the use
of cheaper
carbon source is needed
.
M
any
waste materials such as
food wastes
, potato starch wastewater,
alpechin
, and
wastewater
sludge can be used to make bioplastics

(Luengo et al., 2003)
.


o
The most widely produced microbial bioplastics are PHB, PHA and their derivatives

o
(Luengo et al., 2003).





5

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list


Summary paper 1:


Introduction


Alcaligenes
eutrophus


a bacteria that naturally produces PHB as an intracellular
metabolite and also as a Carbon source when the environmental conditions are
unfavourable was used to produce PHBs that could then be used to produce
bioplastics.


Previous studies had shown that activated microorganisms in the waste water sludge
can produce PHBs that could later be harvested.


Various simple organic sources can be used and this case malt refuse from a brewery
was used as Carbon and nitrogen source to make PHBs.


Methods:

o
Alcaligenes
eutrophus

and
Alcaligenes
latus

obtained form external sources were
cultured on agar plates by monthly sub cultures.

o
Liquid feed medium was prepared using
4 g maltose, 0.2
g
K2HPO4
, 0.4 g (NH4)2SO4,
0.02 g MgSO4"7H20, 0.01 g
citrate
-
Fe
(III),
0.01g
yeast

extract
, 0.01 g
meat

peptone, and
200
mL

tap

water
.

o
Fermentation

medium
was

prepared

using malt and
soya

wastes

which

had
the

ratios

of

7:1 and 8:1 C:N
contents

respectively
.

o
Nitrogen

limited medium
was

also

prepared
.

o
Fermentation

was

carried

out

using
computer

controlled

fermenter

under

set
conditions

and
extraction

and
precipitation

of

the

polymers

done using
centrifugation
.

o
Various

analytical

methods

were

then

used

to make
observations

and
conclusions
.



6

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list


Summary paper 1

Results:


In the first part of the experiment involved
using
A
lcaligenes
trophus
.
V
arious ratios of
butyric acid and
valeric

acids were used as
as carbon sources.


Results are shown in table 1.


In the second part of the experiment,
Alcaligenes
latus

was used to ferment the
sugars to bioplastics and it was then
observed that the polymer yield increased by
almost 50% with increasing C:N ratios.


When using malt waste there was an increase
of 70% polymer /cell. This can be seen in the
figure 2.

Discussion:


When using the
valeric

and butyric acid as
substrates, it was observed that the higher the
acid ratios, the higher the polymer yield. It
was also noted that the plastic obtained from
100%
valeric

acid were much softer and more
ellastic

while those from 100% butyric acid
were highly brittle.


Using malt waste as a C source resulted in the
formation of
bioploymers

of
coploymer

composition of 100% PHB, 100% PHB and 8%
PHV while using soy waste produce
bioploymers

of copolymer composition of 79%
PHB and 21% PHV.


It was concluded that by manipulating the
type of substrate to use, the properties of the
bioplastic

could also be manipulated thus
creating quality products.


T









7

sample

Butyiric:
valeric

ratio

Polymer

yeild

PHB:P
HV

ratio

Meltin
g
point

1

100:0

0.18

100:0

177.6

2

80:20

0.41

88:!2

144.4

3

60:40

0.15

70:30

133.3

4

40:60

0.10

65:35

127.1

5

20:80

0.12

49:51

109.2

6

0:100

0.06

46:54

99.2

table 1:polymer yield by
alcaligenes
trophus

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list



Summary paper 2

8

Introduction:


PHB is the most known
polyhydroxyalkanoate

(PHA). PHB is accumulated by a large
number of bacteria under conditions of nutrient limitation and in the presence of an
abundant source of carbon


The nature and the proportion of polymer produced by bacteria are controlled by the
carbon source used during culture


Because rhizobia can accumulate
PHB during
growth, the purpose of this study was to
evaluate the potential of producing PHB
by fast
-
growing rhizobia cultivated in sludge
and in industrial
wastewater.


Methods:


Two industrial wastes were used namely: wastewater obtained from starch and a
slaughterhouse and another sample was obtained from secondary sludge at a
wastewater treatment
faicility

and
alkalline

treatment was done to
hydrolyse

the
organic matter in the sludge.


Four microbial strains were used for the study:
Sinorhizobium

meliloti

(A2);
Rhizobium
leguminosarum

bv

viciae

(
USDA23370);
Rhizobium
leguminosarum

bv

phaseolus

(USDA2671),
and
Rhizobium

156
leguminosarum

bv

trifolii

(ATCC14480)
.


Innoculum

preparation
was

done

with

yeast

mannitol

broth

and
growth

treatments

were

done

using

100mL
of

standard medium.


Growth

of

S.melioti

was

also

done

for
untreated

sludge

and
alkaline

treated

sludge
.
The cell
counts

were

done

on
yeast

mannitol

agar.

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list


Summary paper 2:

Results:


o
it was observed that the starch waste water had more nitrogen, organic carbon and
phosphorus content in relation to the wastewater from the treatment
palnt

and
slaughterhouse.

o
However the slaughterhouse wastewater had the highest C/N ratio.

o
Mean generation time was higher in wastewater sludge than in standard medium.



form figure 1, PHB
yields in standard medium varied for the different strains,
with
values
ranging between 27.41% (for
R
.
leg
.
bv
.
trifolii
) and 40.49% (for
R
.
leg
.
bv
.

phaseoli
)


sludge PHB, production did not exceed 3.7% for all strains
after 72
h of growth.

9

S.Melioti

that was grown in untreated
and treated alkaline
treaaatment

showed differences.

In untreated sludge, the cells had
longer adaptation times while alkaline
treatment increased the cell count and
also reduced the generation time as
shown in figure 2.


1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list



Summary paper 2:

Results:

10

o
From figure 3 it was observed that
S.melioti

grew much better in
slaughterhouse wastewater compared to
starch wastewater.

o
In both the PHB production fluctuated
throughout the study.


Discussion
:

o
All the strains were able to grow in both
the sludge and the wastewater and were
able to utilize the nutrients.

o
Growth was affected by the nature of the
medium.

o
All Rhizobium strains accumulated
around 24% to 40% PHB that was ten
times more than obtained in wastewater
sludge.

o
This could be attributed to the fact that
standard medium had a better C sources
than the waste water sludge. The PHB
content in the sludge can be increased
by pre treating it so improve the carbon
content.

o

S. melioti grown in wastewater sludge
also accumulates more PHB compared to
the starch waste water though the cells
grow less over time and produce less PHB.
This problem could be over come by
using a fed batch culture and harvesting
the cells before they enter the stationary
phase.

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list


Comparisons:


From both the papers it was possible to say that PHB production is possible from
industrial waste be it food of wastewater.



From both the papers it could be observed that the main hindrance to PHB
production was the amount and type of carbon source required to enhance the
PHB production from industrial waste.



Though industrial waste provides a good and cheap starting point for PHB
production, there still needs research done into how PHB production can be
turned into a large scale process.



Both papers also managed to illustrate that it was possible to obtain PHB and this
was backed up with evidence from other published work as well.



It was possible to say that micro organisms are quite vital in the production of PHB.



As mentioned the main hindrance was exhaustion of Carbon source. These
obstacles could be overcome by use of fed batch cultures and harvesting the
cells before they enter the stationary phase as mentioned in summary paper 2.



From both papers it was observed that the ratio of C:N formed a vital part in the
formation of PHB.



From both summary papers, it can be concluded that PHB production from sludge
and other wastewater is more successful in producing PHB than for industrial food
waste.



This could have been due to the types of bacterium used as well as the fact that
wastewater seems to have a richer amount of carbon sources and thus form
better substrates for growth unlike butyric acid and valeric acid that are nor as
rich in organic carbon. Pre
-
clinical treatment of the wastewater seemed to also
have improved the PHB production as noticed in summary paper 2.



The methods used were completely different except for the fermentation.




11

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list


Critical comments:

o
The quality of work is appropriate for small scale. However it is not
applicable in large scale due to the costs related to the production
of PHB. Control of the carbon source would also be difficult in large
scale.


o
This experiment was also not done at large scale thus it would be
impossible to know whether it would work or not.


o
The use of microorganisms for the production of PHB could be
supported by other work that was published hence it was possible to
use to them in the study based on previous studies that showed that
PHB produced by these organisms could be harvested and used to
produce bioplastics.


o
Both the papers do not also touch on the how PHB production could
be done more effectively even on a small scale. They both give very
scanty solutions to the shortcomings that were faced in the study for
example; the carbon sources to use. At the end of both the studies, it
is not clear which carbon sources would be very effective and
information on how to improve the PHB production remains deficient
even until the end.


o
These papers do however give an idea of what microorganisms would
be effective at producing PHB and it can be said that Rhizobium
would be efficient judging from the results obtained.


o
The summary papers give an idea that wastewater would be better
for the production of PHB in case large scale production was required.


o
Controls were used in paper 1 was not very clear while paper 2 had
controls in the form of untreated sludge and alkaline treated sludge.






12

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list


Personal comments:


Both of these papers are an important stepping stone for the production of
bioplastics as a way of averting the effects of global warming resulting
form incorrect disposal of industrial waste



These summary papers will provide a good reference for further research
that will be done in the field of bioplastics.


13

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list


Reference list


Kumaravel, S., Hema. R.,
and

Lakshmi,R.
“Production of Polyhydroxybutyrate (Bioplastic)
and its Biodegradation by Pseudomonas Lemoignei and Aspergillus Niger,”
E
-
Journal of
Chemistry
,
7
, (S1),
pp. S536
-
S542, 2010. doi:10.1155/2010/
14854.


Luengo, J.M., Garcia,B., Sandoval, A., Naharro, G. and Olivera, E.R. “Bioplastics from
microorganisms” (2003)
Current opinion in microbiology
, 6(3) 251
-
260.


P, H. Yu, H. Chua, L. Huang A, W. Lo, and Q. Chen G. 1998. "Conversion of Food Industrial
Wastes into Bioplastics."
Applied Biochemistry and Biotechnology

70
-
72 (1): 603
-
14.
doi:http://dx.doi.org/10.1007/BF02920172
.


Rebah,F.B., Prevost, D., Tyage, D.R. and Belbahri, L. “Poly
-
β
-
hydroxybutyrate production
by fast growing rhizobia cultivated in sludge and in industrial wastewater” (2008).
Applied Biochemistry
and biotechnology
. 158: 155
-
163. DOI 10.1007/S12010
-
00808358
-
1.






14

1.
Author profile


2.
Summary
papers used


3.
Executive
summary


4.
introduction


5.
Summary
paper 1


6.
Summary
paper 2


7.
Comparisons


8.
Critical
comments


9.
Personal
comments


10.
Reference list