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2. INTRODUCTION

2.1. A great challenge to environment

Pollution is a condition in which contaminants are introduced in to the natural

environments leading to adverse changes in the surroundings and human activity is

the main cause for the same. Pollutants or contaminants are the components that cause

pollution and they may be foreign chemicals, substances or different forms of energy

like heat, noise etc. Pollution may arise in different geographical locations leading to

deformations in soil, water or air. Among different types, marine pollution is one

among the major pollutant due to pollution caused by various transport vehicles such

as ship, ferry etc. and entry of various agricultural, industrial wastes into ocean water.

Water from river and other water bodies flow and meet in the ocean. This carries

various waste materials which are harmful for the marine organisms and cause their

death (Dash et al., 2013).

Pollutions may lead to critical problems in the global geochemical cycles as

well as the sustainable habitation of humans as well as other organisms. Various

sources of pollutants were presented in Figure1. Even though other organisms suffer

from the adverse effects of natural changes, however, the main culprit is human.

Various types of hazardous substances can enter the natural environment by a number

of natural and/or anthropogenic activities, disturbing the living systems along with

many adverse changes in the environment (Kampa and Castanas, 2008).In different

urban areas huge megaplexes have been constructed which are not sustainable and

they experience problems with waste management, heat islands, increasing pollution

and crowding of increasing population etc (William, 2011). CO2 is toxic for pregnant

women and when exposed, the fetus may be harmed. Likewise, car exhaust gases

damage health of both adults and children, leading to change in behaviour and

psycho-social development of children (Chelala, 2010; Markertet al., 2011).

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Fig. 1. Various sources of pollutants

Enlarged pollution over the surface of earth is creating precarious problems in

normal living circumstances of human as well as other flora and fauna. The increase

of temperature on Earth’s surface is the result of ozone layer depletion and

entrapment of greenhouse gases. In India, air quality data have been collected by

NEERI (National Environmental Engineering Research Institute) from ten different

cities of India such as Delhi, Kolkata, Mumbai, Chennai, Cochin, Kanpur, Nagpur,

Hyderabad, Jaipur and Ahmedabad. From those data, Kolkata was found to be the

most polluted city mostly with SO2 followed by Mumbai, Delhi, Ahmedabad, Kanpur,

Hyderabad, Chennai, Nagpur and Jaipur. Jaipur was placed in the first position to be

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polluted with NOx. SPM (Suspended Particulate Matter) level was found to be

highest in Delhi and Kolkata and lowest in Mumbai and Chennai. In Delhi, air

pollution level was found to be highest among all other cities. According to a report,

level of SO2 in atmosphere of Delhi has been recorded as 0.223 ppm, whereas in

Germany and USA 0.05 and 0.1 ppm are the permissible limits respectively.

Methyl isocyanide leaked out from pesticide storage tanks in Bhopal, Madhya

Pradesh, in 1984, killed over 3000 persons. According to a guide of WHO, the lead

level of environment is 2μg/m3 (Verma and Agarwal, 2004). Many cities of India and

various countries of world have crossed this level of lead. Excess growth of

phytoplankton was first observed in the water bodies of Europe and North America.

Chemical wastes out from factories near Mirzapur, Uttar Pradesh have been reported

to contain free chlorine which is the sole reason for the heavy mortality of fishes of

Son River, Bihar. In the big cities of India such as Mumbai, Delhi, Kolkata, Chennai,

the contribution of vehicles to the air pollution is about 35%. A recent report on water

pollution has described that daily around 29001million liters of liquid dirt are

produced in India. In Punjab, India, during 2009, Uranium poisoning was detected,

resulting from fly ash of thermal plants which led to birth defects in children of

Bhatinda and Faridkot. To control noise pollution a new rule has been framed in the

country that noise should not exceed the normal level of 65 decibel. (Source:

ethesis.nitrkl.ac.in/4721/1/411LS2124.pdf).

2.2Plastic - a foremost ecological noxious waste

Although Plastics are the foremost noxious waste, they are considered to be a

bubbly métier for humanity. We should be very grateful to Alexander Parke who

presented the major revolutionary contribution to the development of plastics from

cellulose nitrate in the 1850’s. In the current age, plastics play many more dynamic

roles to mankind as they have versatile qualities. In table 1 major types of plastics in

usage were presented. They become an essential commodity to enhance the comfort

and quality of life. They are a needed part of almost all industries and have influence

in medicine too. The popularity of plastics in packaging and other applications is

primarily endorsed to the exclusive characteristics of the material. These include light

weight, good mechanical strength such as tensile properties, tear resistance, and

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resistance to degradation, readily controllable and greater optical properties,

biological inertness, easy processability, low cost, and excellent durability. Because of

the enormous multipurpose nature of plastics to be made into products of varying

strength and flexibility that we find plastic products ranging from car bodies, home

and office furniture, computers, water bottles and as package materials for almost

everything that needs transportation and storage.

Table 1. Major groups of plastics and their applications

S. No. Types of plastics Applications

1 HDPE High-density polyethylene Milk jugs

2 LDPE Low-density polyethylene Plastic bags

3 LLDPE Linear low-density polyethylene Plastic bags, sheets, stretch sheets

4 PET Polyethylene terephthalate Soda bottles

5 PP Polypropylene Long underwear

6 PS Polystyrene Disposable razors, CD case,

packing foam

7 PVC Polyvinyl chloride Pipes

Source:http://www.epa.gov/osw/conserve/materials/plastics.htm

2.3Hitches associated with the use of synthetic plastics

Today accumulation of non-degradable plastic bags in the environment is one

of the main causes for pollution. Fletcher (1993) stated that conventional

petrochemical plastics are recalcitrant to microbial degradation. Excessive molecular

size might be mainly responsible for the resistance of these chemicals to

biodegradation and their persistence in soil for a long time. These non-degradable

petrochemical plastics accumulate in environment at a rate of 25 million tons per year

(Lee, 1996). Some detrimental effects of plastics were presented in Figure 2. The

Times of India on Apr 4, 2013 stated the Supreme Court proclamation as "We are

sitting on a plastic time bomb”. The Central Pollution Control Board (CPCB) reported

that India generates 56 lakh tonnes of plastic waste annually, with Delhi accounting

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for a staggering 689.5 tonnes a day and "Total plastic waste which is collected and

recycled in the country is estimated to be 9,205 tonnes per day (approximately 60% of

total plastic waste) and 6,137 tonnes remain uncollected and littered”. The four metros

are major culprits in generating such waste in which Delhi producing 689.5 tonnes a

day, followed by Chennai (429.4 tonnes), Kolkata (425.7 tonnes) and Mumbai (408.3

tonnes). The figures only serve to confirm the common sight of mounds of plastic in

industrial, residential and slum areas of Indian cities and towns. As 40% of plastic

waste is not recycled, the daily addition to untreated plastic in Delhi is estimated at

275.6 tonnes, followed by Chennai (171.6 tonnes), Kolkata (170 tonnes) and Mumbai

(163.2 tonnes).

Fig. 2. Complications associated with plastics

The CPCB said that 15,342.46 tonnes of plastic waste was generated every

day in 60 major cities and, amounting to 56 lakh tonnes a year. At present, plastics are

being accounted for about 21% of all (paper, glass, tin plate. etc.) packaging

materials. Packaging materials account for 25% of the total production of plastics in

India, but in terms of consumption, they account for 52%. Plastic waste produced is

around 2.0 million tonnes. Though plastics constitute only about 2.4% (world

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average) of the total municipal solid waste, they are perceived as a major threat

because of their long life and light weight.

In India, plastic waste accounts for only 0.6% of municipal solid waste,

whereas in urban areas of Kerala, it is as high as 4 – 6%.A study conducted by the

National Environmental Engineering Research Institute (NEERI) for the Brihan

Mumbai Muncipal Corporation, which handles more than 5,500 metric tonnes MSW

per day shows that plastic waste is 0.75 %.When we compare this to the plastic

content of MSW in 1960 we find that it contributed only to 1% then. Table 2

describes about the plastic waste usage in world and in India.

Table 2. Rate of plastic waste consumption

S.

No

Description

World

India

1 Per capita per year

consumption of plastic (kg)

24 6-7

2 Recycling (%) 15-20 60

3 Plastic in solid waste (%) 7 9

(Source: Plastics for Environment and Sustainable Development, ICPE, Vol. 8, Issue

1, Jan- Mar 2007)

2.3.1 Immensity

The first commercial plastic was developed over one hundred years ago, but

the plastic became major consumer material only after the growth of the

petrochemical industry in the 1920s. Now plastics have not only substituted many

wood, leather, paper, metal, glass, and natural fiber products in many applications, but

also have enabled the development of entirely new types of products that are so

versatile in use that their impacts on the environment are enormously wide ranging

Once hailed as a 'wonder material', plastic is now regarded as a serious worldwide

environmental and health concern essentially due to its non-biodegradable nature.

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Understanding plastics is vitally significant due to the shear amount

manufactured every year.At a global level, polypropylene production and demand

were dominated by developed countries in the early 2000s. The growth of the Indian

plastic industry has been phenomenal - the growth rate is higher than for the plastic

industry elsewhere in the world (Narayan, 2001). A mounting population base,

improving lifestyle, rapid industrialization and economical robustness have resulted in

the substantial growth of polypropylene demand in the developing markets of the

Asia-Pacific region. Figure 3 illustrates the World plastics production from 1950 to

2012. Any change in production could have significant environmental and economic

consequences. The Energy and Resources Institute in New Delhi has estimated that by

2047, waste generation in India's cities will increase five-fold to touch 260 million

tonnes per year.

Fig. 3. World plastics production 1950-2012

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2.3.2 Energy

Most plastics are made out of petroleum products and so plastics production

has an impact on petroleum consumption. The total oil consumption of the world in

2008 was 87.2 million barrels a day. Known oil reserves total 1.24 trillion barrels,

which at the current rate of consumption would last 41 years. 99% of plastics

feedstock comes from petroleum. Ethylene, propylene, and styrene are extracted

directly from crude oil. The amount of oil used to make plastics is 4% of total oil

consumption. However, more than 4% of the world’s oil production actually is used

by plastics since the 4% only accounts for plastic feedstock and not for heat, energy,

and transportation used in making and selling plastics.(British Plastics Federation)

Since the massive amount of oil the world uses in a day even 4% is a very large

quantity of oil.

The energy required to manufacture plastics is huge. The plastics industry in

the United States consumes about 6% of all the energy used by American industries.

In 1998 the plastic resin and plastic materials companies in the U.S. used 1,070

trillion Btu of energy. That much energy was worth about $6 billion. The rubber and

plastics product manufacturers used 320 trillion Btu in 1998. 320 trillion Btu was

worth approximately $3.5 billion. (Source: U.S. Department of Energy and The

society of the Plastics Industry, Inc. Improving Energy Efficiency at U.S. Plastics

Manufacturing Plants.2003).

Typically made from petroleum, it is estimated that 7% of the world’s annual

oil production is used to produce and manufacture plastic. US Energy information

administration in June 18, 2014 reported that in 2010, about 191 million barrels of

LPG and NGL were used in the United States to make plastic products in the plastic

materials and resins industry, which was equal to about 2.7% of total U.S. petroleum

consumption. In addition to petroleum products and natural gas, about 65 billion

kilowatt hours of electricity were used to manufacture plastics in 2010, equal to about

1.7% of total U.S. electricity consumption. With the large amounts of energy involved

even small increases in productivity would lead to substantial energy savings.

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2.3.3 CO2 emanations

With the mounting concern over global warming due to greenhouse gas

emissions the carbon dioxide emissions of the plastics industry require discussion.

The plastics industry generated greater than 2% of the total carbon emissions from

U.S. manufacturers. In 1994 the U.S. plastics industry was responsible for 4.7 million

metric tons of carbon dioxide emissions. The plastics industry had the third highest

carbon emissions in the chemical sector behind industrial organic chemicals and

industrial inorganic chemicals. The total carbon emissions resulting from energy

consumption for the chemical industry were 78.3 million metric tons of carbon

dioxide (U.S. Department of Energy, 1998). In the intervening years plastics

production has increased and one can accept that carbon emissions have increased as

well.

2.3.4 Hindrances on disposal:the hurdle to resource efficiency

Mountains of plastic litter our landscapes and oceans. Solutions to plastic

waste management include source reduction, incineration, recycling and bio- or

photo-degradation. However, most of these have problems accompanying with

them.Incineration of plastics is potentially dangerous and can be expensive. During

the combustion of plastic waste, hydrogen cyanide can be formed from acrylonitrile-

based plastics and may cause potential health hazards. Recycling can be done but is

very tiresome. The sorting of the wide variety of discarded plastic material is also a

very time-consuming process. Moreover, the presence of a wide variety of additives

such as pigments, coatings, fillers, limits the use of the recycled material. In such a

scenario, biodegradable plastics offer the best solution to the environmental hazard

posed by conventional plastics. An inevitable consequence of increased usage of

plastics, particularly in packaging applications, is the increased amounts of

postconsumer plastic. The characteristics of waste depend on various factors such as

food habits, traditions, lifestyle, climate etc. The waste generated due to urban

activities is known as municipal solid waste (MSW). As per 2001 census the urban

population accounts about 27.8 % of overall population (1027 million).

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Table 3 describes the average municipal solid waste production from 0.21 to

0.50 Kg per capita per day in India. Among the states Tamilnadu is the most

urbanized State with 43.9% of population living in urban areas. The present urban

population is expected 341 million in 2010. Kumar et al. (2004) reported that the

waste quantities are expected to increase from 46 million tonnes in 2001 to 65 million

tonnes in 2010. He also reported that per capita per day production will increase to 0.7

kg in 20503, while accurate estimates of their lifetimes in the environment are not

reliably known, plastics are perceived as being exceptionally persistent materials

requiring hundreds of years of exposure to facilitate biodegradation.Scientists have

noted that it will take far beyond our lifetimes for this plastic to erode.

Table 3. Average municipal solid wastes in Indian cities per day

S.No. Population range

(Millions)

Average per capita value

kg/capita/day

1 0.1-0.5 0.21

2 0.5-1.0 0.25

3 1.0-2.0 0.27

4 2.0-5.0 0.35

5 >5 0.50

Source: CPHEEO Manual on MSW management

2.3.5 Plastics at sea

A detailed discussion of the ecological concerns related to plastic debris at sea,

the specific hazards posed by such debris in specific marine species, and the general

impact of plastics on the populations of target species have been published by Day et

al.,1985; Laist, 1987. According to water pollution facts from the National

Geographic, the Great Pacific Garbage Patch holds as many as 750,000 bits of plastic

per square kilometer.

In fact, these oceanic garbage-patches form the world’s largest rubbish dumps,

even larger than those we find on the land. Ocean mammals can get entangled in old

nets and drown because they cannot get to the surface for air. United Nations

Environment Programme estimates that there are 46,000 pieces of plastic litter

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floating in every square mile of ocean. Animals often mistakenly ingested the plastics

as feed. The ingested plastics are clogging their intestine which results in death by

starvation. Birds, turtles, and fish ingest a variety of plastic items and their digestive

systems become clogged. Sea turtles are especially attracted to floating plastic bags

which appear to be jellyfish, one of their favorite treats. Other animals or birds

become entangled in plastic bags and drown or can’t fly as a result and finally die

Thousands of marine animals and more than 1 million birds die each year as a result

of plastic pollution. The plastic bags block the digestive system and cause a slow and

painful death. As Plastics, are being indigestible macromolecules, they cannot be

absorbed through the gut lining of living organisms.

Available evidence indicates that the ingestion of the debris to be the primary

concerns with a variety of affected marine animals including birds, turtles, marine

mammals, and fish. These affected populations seem to seek out the debris (either

mistaking it for prey or because of mere curiosity); such behavior leads to more

mortalities. World Wildlife Fund Report in 2005 reported that plastics can enter the

food chain. It effects on wildlife can be calamitous. Birds become terminally

entangled. World Wildlife Fund Report in 2005 also estimated that nearly 200

different species of sea life including whales, dolphins, seals and turtles die due to

plastic bags. They die after ingesting plastic bags which they mistake for food. Recent

declines in the natural populations of the Hawaiian monk seal, Monachus

schauinslandi, by 4 to 8% per year have been attributed, at least in part, to

entanglement in plastic waste (Fowler 1985, 1987).

2.3.6 Toxicity on life

The health risks associated with plastics have recently gained media attention.

The main health risks of pure plastics involve their monomers. Sometimes monomers

become trapped in a polymer matrix during manufacturing and then leach out later.

Under certain conditions, a polymer can monomerize.

The issues surround the toxicity to human from the single use plastics are

primarily due to their use in packing food stuff. Here drinking water bottles are often

the most talked about sources of toxicity to humans from plastics. Pthalates and

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Bisphenol A (BPA) are the two most tarnished toxin which leach from plastics into

the contained food or water. Moreover when these single use items are discarded

improperly, they often end up in water bodies where they continue to leach these

harmful chemical for a very long time, on account of being non-biodegradable.

Polystyrene has been found to leach styrene into water and food. Styrene is a possible

carcinogen and endocrine disruptor.

National Geographic news in 2004 stated that some polycarbonates like Lexan

have been found to leach Bisphenol-A when heated or exposed to acid. Department of

Health and Human Services in 2007, reported that Bisphenol-A is a hormone

disruptor that can mimic estrogen. Vinyl Chloride, the monomer of PVC, is a known

carcinogen. Some plastics are more likely to leach monomers than others. The main

health risks connected with plastics do not come from plastics themselves but from

additives like plasticizers. European Commission Joint Research Centre in 2003

reported that Di-Isonoyl Phthalate (DINP), a plasticizer used in PVC was found to be

a likely carcinogen. Di (2-ethylhexyl) phthalate (DEHP), a plasticizer used in PVC

was deemed to be so dangerous that its use was banned in Europe.

European Commission, Scientific Committee in 2008 reported that it was

found to be carcinogenic and it caused reproductive harm in that it showed high

toxicity in fetuses. NGN stated that the problems with DEHP were especially

concerning because of its use in medical equipment (source

http://www.fda.gov/cdrh/safety/dehp.html.2002).Phthalates, have been found to

deposit in the fatty tissues of the body, where they act as anti-androgens. Recent

studies suggest that these phthalates have a role to play in human disease like male

reproductive dysfunction, breast growth and testicular cancers.

BPA which is often found in the food grade plastic known as polycarbonates,

also used in hospital disposables, has been found to have an estrogenic side effect

profile. It is found to have detrimental effects on human placental tissues. Therefore

BPA has been linked with premature birth, intrauterine growth retardation,

preeclampsia and still birth. These conclusions are mainly derived from animal

studies which have also shown that BPA has carcinogenic effect on prostate and

breast besides altering the normal development of the prostate and urinary tracts in the

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rodents. There has been experimental evidence for delayed neurological development.

Recent mice studies have shown that estrogenic effect of BPA may also have a role in

insulin resistance and diabetes.

Dioxin, a highly carcinogenic and toxic by-product of the manufacturing

process of plastics, is one of the chemicals believed to be passed on through breast

milk of the mother to the nursing infant. Burning of plastics, especially PVC releases

this dioxin and also furan into the atmosphere.

(Source:http://journalssathyabama.com/ archives/upload/Bio%20 Engineering

%202011% 20%207.pdf). However due to the different manufacturing process

different plastics have different levels of these toxins. Seeing the prevalence of

microwave ovens, it must be kept in mind that heating of the more dangerous plastics

increases the leaching of the toxic chemicals and hence is an important issue with the

rise of precooked and/or frozen meals in plastic containers. Plastic production also

involves the use of potentially harmful chemicals, added as stabilisers or colorants.

Many of these chemicals have not undergone environmental risk assessment and their

impact on human health and the environment is currently uncertain are regarded with

deep vacillation in the much of the world. Their association with durable and horrid

litter sometimes blinds us to their enormous value.

2.3.7 Statues relating to plastic waste management in India

In the last few years, state and central governments have started paying

attention to the issues of plastic waste seriously. Consequently many legislations, acts

and rules have been formulated to bring the situation under control. Responsibility to

protect the environment and enforcing the existing regulation lies within the Ministry

of Environment and Forests (MOEF).

Government of Himachal Pradesh introduced HP Non-biodegradable

Garbage(control) Act 1995 prohibiting throwing or deposing plastic articles in

public places.

The MOEF issued the criteria developed by Central Pollution Control Board

(CPCB) in association with the Bureau of Indian Standards (BIS) for labeling

'plastic products' as 'Environment -friendly' under its 'Eco mark' scheme. One

of the requirements for fulfilling this criterion is that the material used for

packaging shall be recyclable or biodegradable.

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The Prevention of Food Adulteration Department of the Government of India

issued directives to various catering establishments to use only ‘food-grade’

plastics while selling or serving food items. 'Food-grade' plastics meet certain

essential requirements and are considered safe, when in contact with food. The

purpose is to preventing possible contamination, and to avert the danger from

the use of the recycled plastics.

Recycled plastic manufacture and usage rule(1999)addresses the issue of

plastic bag. The rule prohibits the usage of carry bags and containers made of

recycled plastic bags for storing, carrying and dispensing or packaging of

foodstuffs.

But we all know about the counterbalancing disadvantages…..

Plastic litter disfigures the oceans and the coastlines. Ingestion of plastic kills

marine creatures and fish. Perhaps 5% of the world’s cumulative output of

plastic since 1945 has ended up in the oceans. Shopping bags and other

packaging are strewn across the streets and fields of every country in the

world.

Plastics use valuable resources of oil.

The plastics industry uses large amounts of energy, usually from fossil fuel

sources which therefore adds to the world’s production of greenhouse gases.

The durability of plastics means that without effective and ubiquitous

recycling we will see continuing pressure on landfill. Although plastics do not

represent the largest category of materials entering landfill, position held by

construction waste, they are a highly visible contributor to the problems of

waste disposal.

The manufacturing of conventional plastics uses substantial amounts of toxic

chemicals.

Some plastics leach small amounts of pollutants, including endocrine

disruptors, into the environment. These chemicals can have severe effects on

animals and humans. (The solution to this problem is to avoid using original

raw materials - either monomers or plasticizers -that might produce such

compounds when the plastic is in use or has been discarded).

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Now a day, management of plastic waste is agreat mayhem to environment.

Although plastic has many advantages its non-biodegradability is a major drawback,

which forced us to think upon a material which can replace plastic. In recent years

there has been a shift in public opinion, with people becoming more ecologically

aware. The shift in public opinion and political influence combined with the

increasing price of oil, has driven industries to investigate biodegradable alternatives

to plastic, which are not manufactured using petrochemical methods. Materials

produced from synthetic polymers are widely used for a diverse range of applications

in modern society. The production of biodegradable alternatives with greater

compatibility in the environment is necessary if the applications continue to grow.

The world needs to find a solution that gives us continued access to plastics but

avoids these serious problems. Bioplastics are considered to be an important

component of global sustainability.

2.3.8. An alternate to plastics- Bioplastics……

Bio-plastics are bio-based, biodegradable plastics with almost similar

properties to synthetic plastics. Biodegradation can be explained as a chemical

process during which micro-organisms that present in the environment convert

materials into natural substances such as water, carbon dioxide, and compost. The

term bio-based means the material is partly derived from biomass (plants). Synthetic

plastics remain in the environment for long time as they are resistant to degradation

(Aminabhavi et al.,1990). Bioplastics are made from variety of sources like

polysaccharides, lipids and also proteins (Averous, 2004; Hernandez-Izquierdo and

Krochta, 2008; Siracusa et al., 2008; Gonzalez-Gutierrez et al., 2010). A few

examples of protein used as substrates for bioplastic production are soy protein

(Mohanty et al., 2005; Tummala et al., 2006; Zheng et al., 2003), wheat gluten

(Domenek et al., 2004; Gomez-Martinez et al., 2009; Jerez et al., 2005; Song and

Zheng, 2008; Sun et al., 2008; Zuo et al., 2008), zein (Kim, 2008), rice and egg

albumin (Jerez et al., 2007; Gonzalez-Gutierrez et al., 2009).The petroleum based

conventional plastics are non-renewable where the feed stocks are reinforced by

carbon fibres (Williams et al., 2000).

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Renewable resource feed stocks of plastics include polymers derived from

microbial culture reinforced with natural fibers such as cellulose, jute etc. (Bismarck

et al., 2002). The accumulation of synthetic, petroleum derived plastics in the

environment is a major cause of pollution. So the methodology to produce plastic,

which is an essential polymer used in our day to day life, using microbial product is a

novel approach. It will reduce the environmental pollution as well as the use of

petroleum to make plastic bags. So it can be said in one word that bio-plastic is eco-

friendly.

Biodegradable plastics can be divided into three categories:

Chemically synthesized polymers: Polyglycollic acid, polylactic acid, poly(ε-

caprolactone), polyvinyl alcohol, poly(ethylene oxide) fall into this category.

These are susceptible to enzymic or microbial attack. Since they do not match

all the properties of plastics, they are not commercially viable as substitute for

plastics.

Starch-based biodegradable plastics: In this type, starch is added as filler and

cross-linking agent to produce a blend of starch and plastic (for example,

starch– polyethylene). Soil micro-organisms degrade the starch easily, thus

breaking down the polymer matrix. This results in significant reduction of

degradation time. But such plastics are only partially degradable. The

fragments left after starch removal are recalcitrant and remain in the

environment for a long time.

Polyhydroxyalkanoates (PHAs): These are the only 100% biodegradable

polymers. They are polyesters of various HAs which are synthesised by

numerous micro-organisms as energy reserve materials when an essential

nutrient such as nitrogen or phosphorus is available only in limiting

concentrations in the presence of excess carbon source. They possess

properties similar to various synthetic thermoplastics like polypropylene and

hence can be used in their place. They are also completely degraded to water

and carbon dioxide under aerobic conditions and to methane under anaerobic

conditions by microorganisms in soil, sea, lake water and sewage.

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2.3.9. The protagonist bioplastics

The bioplastics industry is much smaller, with 2011 probably seeing a total

output of about 1m tonnes, or less than half of one per cent of total world plastics

output. But the growth rate of bioplastics is much higher. Most sources suggest that

this part of the plastics industry is growing at least 20% a year. The reasons for this

buoyancy are discussed later in this note. (Source: http:// www. gtai.com/ homepage/

info-service/ publications/ ourpublications/ germany-investment-magazine/vol-2011/

vol-012011/ industry-report-4/).

2.4. An exclusive study for recycling

Some bioplastics are as robust and durable as their oil-based equivalents.

Others will rapidly break down in commercial composting plants. These rapidly

biodegradable plastics have high value in some circumstances such as when plastics

become inevitably mixed with other streams of compostable waste and would

otherwise need to be hand separated. For example, quantities of plastic material are

used in greenhouse applications. Conventional plastics would have to be separated by

hand at great expense and usually then sent to an incinerator or landfill. A more

substantial application also arises in the horticultural sector.

Many field grown vegetables are covered in a thin semi-transparent

polypropylene mulch to help maintain even temperatures, reduce water loss and

protect the crop from insects. The mulch generally only lasts for one season and then

it has to be collected up and returned for recycling. This is a complex and expensive

process. Bioplastic mulch that will dissolve in the soil over the winter is much better

because it saves time and money but also adds to the carbon content of the soil,

helping to maintain fertility. In other important agricultural uses, such as for strimmer

cord (‘weedwacker’ in the US, full biodegradability means that small pieces of plastic

filament do not persist in the environment).

Another example, likely to become one of the largest single applications for

bioplastics, is single use catering utensils. Restaurants and coffee shops generate three

streams of waste: unused food, packaging (for example of sandwiches) and utensils

such as cutlery. It is highly beneficial as well as being advantageous to the brand

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image of the restaurant to use fully compostable packaging and utensils. All the waste

can be put into one bin and shipped to the composting facility without further

intrusion or labour cost. The thick pieces of plastic cutlery will need to shred at the

composting site to inspire rapid biodegradation but this can happen automatically.

Although fully degradable cutlery costs about four times as much as conventional

plastic utensils, the reduction in time spend separating out plastics from food waste

and, second, reducing landfill cost, more than justifies the expense. As well as

compostable utensils, it makes sense to use bioplastic film to provide the windows in

cardboard sandwich packets so that the packaging can also be added to the stream of

compostable items.

Some American towns and cities are beginning to move to mandatory use of

biodegradable plastics for single use catering utensils, including plates, cups and

cutlery. Seattle, for example, has introduced an ordinance that obliges restaurants to

only use bioplastics that will degrade in the city’s composting plant. The final

imposition of this rule has been delayed by problems obtaining cutlery that is

sufficiently compostable but the rules are becoming stricter here and in other towns

and cities wanting to reduce use of landfill. Seattle uses a landfill site 320 miles from

the city - about the distance from Newcastle to London - creating a huge incentive to

avoid high transport fees. As disposal sites fill up around the world, the need either to

recycle plastics or to compost them can only increase, adding further buoyancy to

bioplastic sales. In a similar move, municipalities around the world collecting food

waste from homes are now often providing compostable plastic bags into which the

food goes prior to collection. Householders benefit from easier and more hygienic

storage of the waste. (Source: http:// www. seattle.gov/ util/ groups/ public/ @spu/

@usm/ documents/webcontent/cos_001786.pdf).

2.4.1. Litter

The best understood advantage of biodegradable bioplastics lies in the

reduction of permanent litter. Plastic single use shopping bags are the most obvious

example of how plastics can pollute the environment with huge and unsightly

persistence. A large fraction of the litter in our oceans is of disposable plastic bags.

Cities and countries around the world are taking action against the litter, sometimes

by banning non-degradable plastic bags entirely. Biodegradable bioplastic bags will

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be allowed in Italy, providing a huge boost to the European market for these products

not least because until now the country has been the largest European market for

single use shopping bags.(Source: http: //www.seattle.gov/ util/groups/ public/@spu/

@usm/ documents/ webcontent/cos_001786.pdf).Italy has decided to block the use of

non-biodegradable single use shopping bags from the beginning of 2012. In India,

some of the states have been planned to avoid plastics usage. In September 2009,

“Delhi Pollution Control Committee” (DPCC) had filed a case against “Bata Shoe

Stores” for using and keeping stock of plastic bags against the “Environment

Protection Act” and the notification of the Delhi Government banning the use of

plastic bags.

To emphasis in TamilNadu, Mr.Rajendra Ratnoo, the District Collector of

Kanyakumari district – a senior civil servant from the Indian Administrative Service

(IAS) officially banned and enforcement on using plastic bags and cups went into

effect on April 1st 2010 after several months of the popular “quit plastics” campaign

planning reported in THE HINDU February 11, 2010. In south zone of TamilNadu

especially in Thanjavur district most of the educational institutions are being plastic

free campus. These legislative changes represent a clear trend as politicians respond

to the irritation over the persistence of plastic bag litter in the world’s seas, rivers and

rural and urban environments. Some places will continue to allow plastic bags that are

genuinely biodegradable and meet the published standards for compostability.

2.4.2. The carbon imprint of plastics

Calculating the greenhouse gas reductions arising from the use of bioplastics

is a complex and controversial area. But it is nevertheless important to try to quantify

the benefits from making plastics from biological materials in order to encourage

further debate and research. The first point to make is 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. If the resulting

bioplastic degrades back into CO2 and water, this sequestration is reversed. But a

permanent bioplastic, made to be similar to polyethylene or other conventional

plastics, stores the CO2 forever.

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Even if the plastic is recycled many times, the CO2 initially taken from the

atmosphere remains sequestered. Bioplastics can generally be processed at about 140-

1800C compared to temperatures of up to 3000 for conversion of petrochemicals to

plastics. Most calculations of the energy used and greenhouse gases created in the

production of conventional plastics produce much higher numbers. To be clear, the

implication is that those bioplastics that do not degrade might therefore have a carbon

footprint of well under half the conventional equivalent. Braskem, the large Brazilian

producer manufacturing both bioplastic and oil-based equivalents, has calculated

much higher figures for the capture of CO2 by a growing sugar cane plant. It estimates

a net sequestration (that is, a negative footprint) of about 2.3 kilogram of CO2 for

every kilogram of biopolypropylene manufactured. It compares this to a carbon

footprint of over 3 tonnes for polypropylene made from oil, meaning a net gain of

over 5kg of CO2 for each kilogram of plastic. (Source:

http://www.braskemir.com.br/braskem/web/arquivos/Conference_Mar2011_Citi_1x1

_v2.pdf).Many landfill sites in the UK collect the methane from rotting organic

materials and burn it for electricity production. Nevertheless some methane escapes

and adds to global warming.

This is an important potential saving; if all plastics were switched to biological

feedstocks and the carbon footprint benefit was as high as much, the reduction in

global greenhouse gas emissions would be about 5% of current total. If, on the other

hand, the bioplastic is of a degradable type the advantages over conventional plastics

are less pronounced. The plastic will compost back into carbon dioxide and water,

returning all the sequestered carbon to the atmosphere. In the illustration given above,

the savings from making the bioplastic compared to the oil-based comparator would

be relatively small, but nevertheless still positive.

The crucial point, not well understood by commentators or by the public is

that compostable plastics will typically have a much larger carbon footprint than ones

that are manufactured to be permanent. The return of the CO2 to the air reduces the

sequestration of organic material. This situation would be made worse if the bioplastic

did not compost in air, but rotted in an oxygen poor landfill. In these circumstances,

the plastic would degrade into methane (CH4) and other byproducts. Methane is a

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global warming gas of greater impact than CO2 and so the full carbon footprint needs

to include any uncaptured CH4 produced in landfill. Most - but not all - research

shows that the conditions in well maintained landfill sites are too dry for degradable

plastics to actually rot. In these circumstances, the bioplastics will therefore

permanently sequester carbon. Figure 4 emphases the concept of sustainability at

economic, social and environmental level of bioplastics.

Fig. 4. Concept of sustainability at economic, social and environmental level of

bioplastics

Hence bioplastics are important in helping consumer goods companies present

their brands in a favourable light. Recyclable or compostable packaging made from

biological materials can be used to make their products more environmentally friendly

in the eyes of consumers. Although bioplastics may be more expensive per kilo of

packaging, the extra cost is more than outweighed by the benefits seen by purchasers.

The client lists of the major bioplastic suppliers include most of the largest and best-

known consumer goods companies, ranging from the Shiseido cosmetics brand to

Ecover, the Belgian cleaning products company.

We have identified five major advantages of bioplastics in this note as follows,

Potentially a much lower carbon footprint

Lower energy costs in manufacture

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Do not use scarce crude oil

Reduction in litter and improved compostability from using biodegradable

bioplastics

Improved acceptability to many households.

2.4.3 Significance of the study

The study is significantly important because it tends to identify bacterial

species from uncharted marine soil sample seasonally to synthesize PHA. The

strategies to upgrade and optimize the PHA production using a renewable carbon

sources from agroindustrial wastes combined with unexplored marine bacterial

isolates has been chosen as research goal.Subsequent reduction of pollutants and

many other important advantages which could be generated from this work are:

a) Plastics have been an integral part of our life. However, disposal of these non-

biodegradable (petrochemical derived) plastics poses a threat to our

environment. The current worldwide demand for plastics is in excess of 100

million tonnes per year as said by Abou Zeid (2001). Therefore, replacement

of non-biodegradable plastics by degradable will aid to circumvent

environmental problems.

b) Among the substrates required, the carbon source is of prime significance in

the case of PHBs production. The main materials used for the accumulation of

PHA by microbes are usually fructose and volatile fatty acids (VFA) which

are both expensive. Therefore, the use of cheaper carbon sources can lower the

production cost of PHB. So organic pollutants discharged from many

industries contribute a major impact in microbial bioprocessing technology.

Thus, the improved use of wastes can reduce the pollution load due to the

carbon uptake simultaneously promoting rate of biopolymers (PHB)

production.

c) For the commercialization of PHA, a great deal of determination has been

dedicated to reduce the production cost by the isolation, development of better

microbial strains and more efficient recovery processes. So isolation of

bacterial consortium from marine sources has been paying much attention due

to reliable results. This evaluation may be useful to isolate novel bacterial

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species with the ability to produce significant amounts of PHB in the very

simple medium compared to previous known bacteria. By utilizing some agro

industrial wastes as carbon sources, the present study enhances the yield and

evaluated the thermostability of the polymer with the intention of

commercialization.

2.4.4 Objectives and scope of the study

Zero plastics to landfill by 2020 and also production process filled without

GMO are the challenging tasks but realistic goal. The success in the biodegradable

plastic strategy largely depends on the isolation of potent PHA accumulating

microbes and optimizing culture parameters for its maximum biosynthesis. Keeping

these facts, the following objectives were set to achieve in the present study. They are,

Isolation and identification of bacteria from soil samples collected from

unexploited coastal area, Sethubavachatram, Thanjavur-district, seasonally for

the period of one year.

Screening the efficacy of PHAaccumulating bacterial isolates by Sudan black

and acridine orange staining method.

Selection of PHA accumulating positive isolates by quantification procedure.

Scaling up the production by inducing UV mutation.

Optimization of pH, temperature and incubation time to maximize PHA yield.

Exploring cheaper agroindustrialwastes as substrates and optimizing PHA

yield.

Validation of PHA by TLC and GCMS.

Evaluate the thermostability of produced PHA.

Molecular characterization of high PHA accumulating isolates by

16S rRNA gene sequencing

Phylogenetic tree construction

Secondary structure prediction

Restriction site analysis