2. Introduction
• 34 million tons of plastic waste was produced per year and 93 % of material was dumped
into oceans and landfills.
• The first environmental problem which leads to plastics is “landfill problem”
• The second environmental problem is “accumulation of plastics in oceans”. a long-
term study in the North Atlantic, one seawater sample contained the equivalent of
580,000 pieces of plastic per km2
• Third problem is incineration of Plastics that generates toxic emissions such as carbon
dioxide and methane.
• The fourth problem is their “non-degradability or durability”
3. Bioplastics
• “Bioplastics” are made from renewable resources such as corn, sugars, potatoes, etc.
and produced by some microorganisms
• Bioplastics were discovered nearly a century ago with Galalith and
Polyhydroxyalkanoates (PHAs) being some of the oldest.
• At present, there are 21 many bioplastics on the market including but not limited to
polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), Mirel and Bio-
PET.
• Starch-based polymers such as blends with polycaprolactone (PCL) and polybutylene
succinate (PBS) currently dominate the market
• The global bioplastics market is thought to be growing about 20%~25% per year.
4. Classification of bioplastics
• Photodegradable bioplastics have light sensitive group incorporated directly into the
backbone of the polymer as additives. Extensive ultraviolet radiation (several weeks to
months) can disintegrate their polymeric structure rendering them open to further bacterial
degradation
• Bio-based bioplastics as “plastics in which 100% of the carbon is derived from renewable
agricultural and forestry resources such as corn starch, soybean protein and cellulose”
• Compostable bioplastics are biologically decomposed during a composting process at a
similar rate to other compostable materials and without leaving visible toxic remainders.
• Biodegradable bioplastics are fully degraded by microorganism without leaving visible toxic
remainders. The term “biodegradable” refers to materials that can disintegrate or break down
naturally into biogases and biomass (mostly carbon dioxide and water) as a result of being
exposed to a microbial environment and humidity, such as the ones found in soil, hence
reducing plastic waste, whereas bio-based sustainable materials.
5. Types of Bioplastics
• Starch-Based Bioplastics -Polymers that contain native or modified starch moieties. Blends of natural or
synthetic plastics with starch as well as polymers produced from the fermentation of starch can also be included
in this group. This accounts for approximately 50% of the global bioplastics market and constitutes many of the
thermoplastics in use today. E.g., Bio-PET, Thermoplastic Starch (TPS)
• Cellulose-Based Bioplastics - Derived from cellulose esters or other cellulose derivatives.Cellulose contains
glucose molecules connected to each other by a β(1,4) linkage which explains why specific symbiotic microbes
are required for its digestion by ruminants.E.g., cellulose acetate, methyl cellulose
• Aliphatic Polyesters - Include materials that are more resistant to hydrolytic degradation.E.g., PHA and PLA 5
• polylactic acids (PLA) and polyhydroxyalkanoates (PHA)
• PHAs are polyesters synthesized and stored by various bacteria and archaea in their cytoplasm as water-insoluble
inclusions. PHAs are usually produced when the microbes are cultured with nutrient-limiting concentrations of nitrogen,
phosphorus, sulfur, or oxygen and excess carbon sources.
• Polylactic acid is a synthetic dermal filler that is injected into your face, causing your body's own production of collagen.
• PLA, created with injection moulding, casting or by being spun, is also used as a decomposable packaging material, film or
for cups and bags. It is used for compost bags, food packaging, disposable tableware, and loose fill packaging.
6. Production of Bioplastics
• Protein-Based Bioplastics - Derived from sources like milk, wheat gluten and other
sources of protein. Very similar to the process of cheese-making. E.g., casein bioplastics
• Lignin-Based Bioplastics - Although lignin has long since been obtained as a byproduct
of cellulose production, it is only with the recent advent of biorefinery projects that this
polymer has gained importance. E.g., PP-lignin polymer blends, PHA-lignin polymer blends,
etc.
• Chitin-Based Bioplstics - Chitin is a biopolymer made of N-acetyl-D-glucosamine units
linked by β(1,4) bonds and is the second most abundant biopolymer after cellulose.
Although chitin is found in the cell walls of yeast and fungi and in the exoskeletons of
arthropods, the primary source of its extraction is from the shells of crustaceans like crabs,
prawns, shrimps, etc. E.g., Chitosan based bioplastics, chitin blends with PP, etc.
In terms of production, bioplastics may be broadly grouped into three types:
i. Polymers directly extracted from biomass
ii. Polymers produced from bio-derived intermediates
iii. Polymers produced by microorganisms.
Contd…
7. Poly lactic acid (PLA) Production
• Lactic acid (2-hydroxy propionic acid), the single monomer of PLA, is produced via
fermentation or chemical synthesis.
• Industrial lactic acid production utilizes the lactic fermentation process rather than
synthesis because the synthetic routes have many major limitations, including limited
capacity due to the dependency on a by-product of another process.
• Three ways are possible for the polymerization of lactic acid
a) Direct condensation polymerization
b) Direct polycondensation in an azeotropic solution (an azeotrope is a mixture of 2 or
more chemical liquids in such a ratio that its composition cannot be changed by
simple distillation
c) Polymerization through lactide formation.
9. Xylose metabolism
in B. coagulans
Metabolic pathways of LAB showing both homolactic
and heterolactic fermentation.
Microbial Poly lactic acid (PLA) Production
10. Advantages of Bioplastics
• Potentially, a much lower carbon footprint. It should be pointed out that the carbon
footprint of a bioplastic is crucially dependent on whether the plastic permanently stores
the carbon extracted from the air by the growing plant. A plastic made from a biological
source sequesters the CO2 captured by the plant in the photosynthesis process.
• Bioplastic is made from renewable resources: corn, sugarcane, soy and other plant
sources as opposed to common plastics, which are made from petroleum
• Energy efficiency. Production uses less energy than conventional plastics. On the other
hand, plastics are made from about 4% of the oil that the world uses every year. With oil
scarcity, the manufacture of plastics becomes increasingly exposed to fluctuating prices
• Eco-safety. Bioplastic also generates fewer greenhouse gasses and contains no toxins.
Bioplastics contribute clearly to the goal of mitigating GHG emissions with only 0.49 kg
CO2 which is being emitted from production of 1 kg of resin. Compared with 2~3 kg CO2
of petrochemical counterparts, it is about 80% reduction of the global warming potential.
11. Disadvantages of Bioplastics
• High costs. It is acclaimed that bioplastics costs two times more than conventional plastics.
However, the amount of large-scale industrial production of bioplastics which are more common in
the future with the implementation of cost reduction is expected
• Recycling problems. Bioplastic material might actually contaminate the recycling process if not
separated from conventional plastics. For example, working with infrared rays in waste separation
system, bioplastics cannot be separated and the separating plastics might be contaminated with
bioplastics
• Reducing raw materials. Bioplastics produced from renewable sources might reduce raw material
reserves. Moreover, in order to reduce energy consumption during the production of bioplastics
and potential competition with agricultural resources for foods and also to provide additional raw
material sources, the exploitation of food by-products is also the current trend
• Misunderstanding of terms. The description of bioplastic as compostable can be confusing. All
bioplastics are not compostable at home like organic food waste but usually require an industrial
composting treatment which is not available at every composting site. Also, bioplastics and related
terms are being misused by various manufacturers to place their products more attractively on the
market. Some slogans used by manufacturers such as “environmental friendly”, “non-toxic”,
“degradable/totally degradable”, are a trick with the uninformed and overwhelmed consumer
• Lack of legislation. Production of bioplastics is projected to increase to over 6.7 million tons by
the year 2018. But still, many countries have not used any law or legislation about their production,
usage or waste management.
13. Disposal of Polylactic acid (PLA)
• It can be difficult to judge if a bioplastic is truly biodegradable, as in the case of PLA, and
this makes its disposal perplexing
• Enzymes required to catalyze the hydrolysis of PLA, such as Proteinase K, are not
available in the natural environment. For this reason, industrial composting of PLA is
more feasible since self-hydrolysis of PLA into lactic acid can take place at high
temperature
14. Disposal of Poly hydroxy alkonates (PHA)
• Most organisms are able to degrade this polymer
through the action of depolymerases or non-specific
lipases, hence, it is easily compostable in even
home composting conditions, leaving behind little to
no remnants.
• Degradation of PHA can start even at 30 °C, which
can be achieved under most composting conditions.
• Although all kinds of PHAs can be degraded under
controlled composting conditions, of the various
types of PHAs, P(3HB) degrades the slowest while
Poly(3- hydroxybutyrate-co-4-hydroxybutyrate)
or P(3HB-co-4HB) degrades quickly.
• Unfortunately, recycling of some PHAs like P(3HB)
may not be feasible since it is not very stable at high
temperatures, and may be difficult to isolate if mixed
with PET and other conventional plastics in recycling
units
15. Biopolymers
• The prefix ‘bio’ in the term ‘biopolymers’ signifies that
these polymers are inherently produced from living
matter.
• Term “biopolymers” was coined in 1833 by Jons
Jacob Berzelius
• Comprising of chain-like structured molecules either
linearly or branched/crosslinked, biopolymers have
found their way into revolutionizing the world of
materials.
• The monomer units of most biopolymers usually
consists of reoccurring molecules of either nuclei acid
of nucleotides, amino acid proteins or saccharides
derived from sugars.
• In recent times, variable uses of biopolymers have
been realized, ranging from additives and blends in
bioplastics to personal hygiene, edible goods and
medical products whilst offering the benefit of eco-
friendly degradation
16. Characteristics of an Ideal Biopolymer
• Should be versatile and possess a wide range of mechanical, physical, chemical
properties.
• Should be non-toxic and have good mechanical strength and should be easily
administered.
• Should be inexpensive.
• Should be easy to fabricate.
• Should be inert to host tissue and compatible with environment.
17. Classification of Biopolymers
• On the basis of their responsiveness to thermal conditions, biopolymers are classified as
elastomers, thermosets and thermoplastics.
• Based on their composition, biopolymers are grouped into three categories as being in the form
of blends, laminates or composites.
18. Biopolymer properties affecting performance & functionality
It is characteristic for biopolymers to have their properties
diverging into three chief categories namely:
• Relative properties, self-reflected by the polymer
• Synthesizing properties, defining the behavioural
qualities during formation
• Component properties, referring to its functional
capabilities.
19. Biodegradable Compostable
Standards
followed
EN17033 acts as the
standard for biodegradable
mulch films while ISO17556
is used to determine aerobic
biodegradation of plastics
Must meet the ASTM
D6400 or EN 13432
standard
Duration > 90% should be converted to
CO2 within two years
Less than or equal to
three months
Byproducts No requirement regarding the
absence of remnants
No physical remnants
should be found and no
toxic byproducts should
be produced
Interrelation All biodegradable materials
are not compostable
All compostable materials
are biodegradable
22. Degradation of bioplastic by enzyme
Polymer degradability and feedstock renewability of
different polymers.
23. • Mainly degradation of polymers depends on environmental factors (temperature,
moisture, acidic nature etc.) and the chemical nature of the polymer.
• Another factors that can affect the rate of degradation are crystallinity, molecular
weight, co-polymer composition and size of the polymer
• Other factors of bio-degradation are the aerobic and anaerobic environment.
Factors affecting rate of degradation of polymers
Basic mechanism of bio-degradation is the oxidation or hydrolysis by enzymes which
eventually improves the hydrophilicity of plastic material, resulting in low molecular
weight polymer which is more friendly for further microbial assimilation
24. Chemical branch Biopolymer Application
Poly-(hydroxy acid) Poly(lactic acid) Food packaging, bags, cutlery products, sheets, floor mats,
containers
Poly(glycolic acid) Medical devices, surgical sutures, pharmaceutical
supplies
Polyhydroxyalkonoate Poly(3-hydroxybutyrate) Disposable films, gloves, medical applications
Poly(β-malic acid) Biomedical devices, biomaterial applications
Poly-(alkylene
dicarboxylate)
Poly(butylene succinate) Injection molding, disposable products like sheets, fibers,
films
Poly(butylene adipate-co-
terephthalate)
Packaging films, compost and plastic bags, agricultural films
Poly(ethylene terephthalate) Bottles, sheet components,
containers for food commodities, pharmaceutical products
Poly-(ether ester) Polydioxanone Medical sutures and implants for slow tissue-healing
process
Aliphatic polycarbonates Poly(ethylene carbonate) Films for food packaging, sacrificial processing materials
Application of Biopolymers
27. “Biosensor” – Any device that uses specific biochemical reactions to detect chemical compounds in
biological samples.
28. Current Definition
A sensor that integrates a biological element with a physiochemical transducer to produce an
electronic signal proportional to a single analyte which is then conveyed to a detector.
30. Father of the Biosensor
Professor Leland C Clark Jnr 1918–2005
31. • 1916 First report on immobilization of proteins : adsorption of invertase on activated charcoal
• 1922 First glass pH electrode
• 1956 Clark published his definitive paper on the oxygen electrode.
• 1962 First description of a biosensor: an amperometric enzyme electrodre for glucose (Clark)
• 1969 Guilbault and Montalvo – First potentiometric biosensor:urease immobilized on an ammonia electrode to detect
urea
• 1970 Bergveld – ion selective Field Effect Transistor (ISFET)
• 1975 Lubbers and Opitz described a fibre-optic sensor with immobilised indicator to measure carbon dioxide or oxygen.
History of Biosensors
32. • 1975 First commercial biosensor ( Yellow springs
Instruments glucose biosensor)
• 1975 First microbe based biosensor, First immunosensor
• 1976 First bedside artificial pancreas (Miles)
• 1980 First fibre optic pH sensor for in vivo blood gases (Peterson)
• 1982 First fibre optic-based biosensor for glucose
• 1983 First surface plasmon resonance (SPR) immunosensor
• 1984 First mediated amperometric biosensor: ferrocene used with glucose oxidase for glucose detection
History of Biosensors
33. • 1987 Blood-glucose biosensor launched by MediSense ExacTech
• 1990 SPR based biosensor by Pharmacia BIACore
• 1992 Hand held blood biosensor by i-STAT
• 1996 Launching of Glucocard
• 1998 Blood glucose biosensor launch by LifeScan FastTake
• 1998 Roche Diagnostics by Merger of Roche and Boehringer mannheim
• Current Quantom dots, nanoparicles, nanowire, nanotube, etc
History of Biosensors
34. 1. LINEARITY Linearity of the sensor should be high
forthe detection of high substrate concentration.
2. SENSITIVITY Value of the electrode response per substrate
concentration.
3. SELECTIVITY Chemicals Interference must be minimised
for obtaining the correct result.
4.RESPONSE TIME Time necessary for having 95% of
the response.
Basic Characteristics of a
Biosensor
36. 1. The Analyte (What do you want to detect)
Molecule - Protein, toxin, peptide, vitamin, sugar, metal ion
2. Sample handling (How to deliver the analyte to the sensitive region?)
(Micro) fluidics - Concentration increase/decrease),
Filtration/selection
Biosensor
37. 4. Signal
(How do you know there was a detection)
3. Detection/Recognition
(How do you specifically recognize the analyte?)
Biosensor
38. Example of biosensors
Pregnancy test
Detects the hCG protein in urine.
Glucose monitoring device (for diabetes patients)
Monitors the glucose level in the blood.
43. Piezo-Electric Biosensors
The change in frequency is proportional to the mass
of absorbed material.
Piezo-electric devices use gold to detect the specific angle at
which electron waves are emitted when the substance is exposed
to laser light or crystals, such as quartz, which vibrate under the
influence of an electric field.
44. Electrochemical Biosensors
• For applied current: Movement of e- in redox reactions detected when a
potential is applied between two electrodes.
45. Potentiometric Biosensor
• For voltage: Change in distribution of charge is detected using ion-selective
electrodes, such as pH-meters.
46. Optical Biosensors
• Colorimetric for color
Measure change in light adsorption
• Photometric for light intensity
Photon output for a luminescent or fluorescent process can be
detected with photomultiplier tubes or photodiode systems.
47. Calorimetric Biosensors
If the enzyme catalyzed reaction is exothermic,
two thermistors may be used to
measure the difference in resistance
between reactant and product and, hence,
the analyte concentration.
48. Electrochemical DNA Biosensor
Steps involved in electrochemical DNA hybridization
biosensors:
Formation of the DNA recognition layer
Actual hybridization event
Transformation of the hybridization event into an
electrical signal
49. Motivated by the application to clinical diagnosis and genome
mutation detection
Types DNA Biosensors
• Electrodes
• Chips
• Crystals
DNA biosensor
51. Biosensors on the Nanoscale
Molecular sheaths around the nanotube are developed that respond to a
particular chemical and modulate the nanotube's optical properties.
A layer of olfactory proteins on a nanoelectrode react with low-concentration
odorants (SPOT-NOSED Project). Doctors can use to diagnose diseases at earlier
stages.
Nanosphere lithography (NSL) derived triangular Ag nanoparticles are used to
detect streptavidin down to one picomolar concentrations.
The School of Biomedical Engineering has developed an anti- body based
piezoelectric nanobiosensor to be used for anthrax,HIV hepatitis detection.
52. Potential Applications
• Clinical diagnostics
• Food and agricultural processes
• Environmental (air, soil, and water) monitoring
• Detection of warfare agents.
53. Food Analysis
Study of biomolecules and their interaction
Drug Development
Crime detection
Medical diagnosis (both clinical and laboratory use)
Environmental field monitoring
Quality control
Industrial Process Control
Detection systems for biological warfare agents
Manufacturing of pharmaceuticals and replacement
organs
Application of Biosensor
54. •Biosensors play a part in the field of
environmental quality, medicine and industry
mainly by identifying material and the degree
of concentration present
Editor's Notes
#27:The first is much too broad
http://www.gentronix.co.uk/images/newscientist.jpg
#28:Can also be to detect a single group of analytes
www.imec.be/ovinter/static_research/BioHome.shtml
