Journal of Environmental Treatment Techniques  
2021, Volume 9, Issue 1, Pages: 148-157  
J. Environ. Treat. Tech.  
ISSN: 2309-1185  
Journal web link: http://www.jett.dormaj.com  
https://doi.org/10.47277/JETT/9(1)157  
A Review: Plastics Waste Biodegradation Using  
Plastics-Degrading Bacteria  
1
2
3
Angga Puja Asiandu *, Agus Wahyudi , Septi Widiya Sari  
1
Department of Biology, Gadjah Mada University, Yogyakarta, Indonesia  
2
Department of Biology, Sriwijaya University, Indonesia  
3
Department of Sociology, University of Bengkulu, Indonesia  
Received: 25/09/2020  
Accepted: 25/10/2020  
Published: 20/03/2021  
Abstract  
Plastic is a synthetic polymer that is widely used in almost every field of life. The massive use of this synthetic polymer has led to the  
accumulation of this polymer in the environment thus polluting the environment. The general techniques in preventing plastic waste as  
landfill, incineration, recycling are considered less effective as they release some hazardous materials to the environment. Thus, the  
appropriate technique is needed to overcome this problem. Biodegradation is an enzymatic degradation involving some microorganisms  
including bacteria. This technique can be used to prevent the plastic waste problem. Plastic waste biodegradation occurred through several  
steps, including biodeterioration, depolymerization, and assimilation. Within this process, bacteria will secrete many enzymes that will  
degrade and convert plastic polymers into microbial biomass and gases. Thus, this process has fewer even no side effect.  
Keywords: Bacteria, Biodegradation, Enzymes, Plastics Waste  
1
Plastics are daily lives related products used in almost every  
1
Introduction  
field of life in all countries (9). They are widely used because of  
their strength and durability. On the other hand, those characters  
lead to plastic resistance to degradation. These insoluble  
recalcitrant polymers take many years to be naturally degraded  
in the environment. This problem encourages plastic waste  
pollution that threatens many living things, including humans  
Plastics are organic polymers containing molecules  
composed of long carbon chains back-bone formed through the  
polymerization (1). They are made of carbon and hydrogen, with  
nitrogen, sulfur, and other various organic and inorganic  
materials derived from fossil fuels (2). Plastics divided into  
natural plastics, semi-synthetic plastics, synthetic plastics,  
thermoplastics, and thermosetting plastics (3).  
(
10).  
The uncontrolled plastics uses started several decades ago  
The massive plastics production has begun in the 1950s,  
which is generally produced for disposable use. Most of the  
plastics waste is non-biodegradable which takes thousands of  
years to be decomposed or degraded (4). In 2010, China was the  
highest plastic waste producer in the world with 8.8 million tons  
per year or 27% of the total world plastic waste production.  
Meanwhile, Indonesia was the second after China as the highest  
plastic waste-producing country in the world with 3.2 million  
tons per year or 10% of the total world plastic waste (5, 6, 4). In  
Indonesia, approximately 15% of the individually daily wastes  
are plastics (7). Based on the European Plastics in 2018, total  
world plastic production reaches 335 million tons per year, as  
much as 60 million of that amount is obtained in Europe. It is  
estimated that the number of plastic productions will be two  
times greater in the next 20 years. Meanwhile, plastic bags are  
the most common form of plastic widely used in daily lives in  
the world. Although plastic products are reusable, they are still  
one of the main factors causing environmental pollution (8).  
have caused many environmental problems related to the  
disposal uses and pollutions of plastics waste. The  
decomposition process of plastic polymers takes thousands of  
years. People usually burn plastics waste to overcome the  
accumulation of plastics waste in the environment yet the  
burning of plastics waste leads to air pollution. It releases toxic  
2
compounds, CO , and dioxins, into the air. Those released gases  
cause lung diseases and cancer (11). As plastics waste is a  
pollutant polluting the land, air, and water ecosystem (12),  
threatening various living things (10), therefore the appropriate  
processing method of plastic waste is necessarily needed to be  
carried out. The application of reuse, reduce, and recycle is now  
widely applied to prevent the problem caused by plastics waste.  
However, this method is less effective, especially for plastics  
waste that has been mixed with other types of waste (8). Also,  
landfill plastics waste processing requires large space, and  
incineration plastics waste processing can produce toxic gases  
into the environment (13). Thus the more effective and  
environmentally safe processing plastics waste method is  
needed. Biodegradation is considered as a more profitable and  
more effective method to prevent this worldwide problem.  
Corresponding Author: Angga Puja Asiandu, Department of  
Biology, Gadjah Mada University, Yogyakarta, Indonesia.  
E-mail: anggahasiandu@gmail.com  
148  
Journal of Environmental Treatment Techniques  
2021, Volume 9, Issue 1, Pages: 148-157  
Biodegradation involves many kinds of plastics degrading  
3
Plastics Waste Problems  
microorganisms  
(14,  
15)  
as  
bacteria, such  
as  
The plastics degradation process in the environment takes up  
0 to 100 years, even reaching 500 years to be degraded  
D.nigrificans, and Pseudomonas alcaligenes (16). They can  
produce various enzymes, both intracellular and extracellular,  
that can degrade plastic polymers to protect the environment  
2
completely (22). Furthermore, the degradation of plastic bags  
and styrofoam containers spend 1000 years (4). It causes  
negative impacts on the environment as decreasing soil fertility  
that contaminated with plastics waste, contaminating water by  
plastic constituents, interfering soil-decomposing organisms, and  
accumulating toxic compounds through the food chains. Also,  
buried plastic waste blocks waterways cause flooding (22).  
Plastics waste in both terrestrial and aquatic environments is  
the main problem of ecosystem balance. It will be worse when  
the plastics have been transformed into invisible microplastics  
that are harder to overcome. The large amount of plastics waste  
dominated by plastic bags has caused various respiratory and  
digestive system problems for thousands of species. Ingested  
plastic waste by animals, mainly aquatic animals such as fish,  
leads to bioaccumulation of the toxic compounds contained in  
the plastic waste. Then the plastic contaminated fish possibly  
consumed by humans resulting in many health problems. It is  
estimated that in 2050 as many as 99% of seabirds will be  
exposed to plastic waste through ingestion (4).  
Plastics waste on the land can be broken down by sunlight  
into smaller parts or fragments polluting soil and water. Those  
toxic fragments may be involved in food chains threatening  
many living things. For instance, polyethylene is gravely  
hazardous for many aquatic species as aquatic mammals, sea  
turtles, and waterbirds when it is consumed accidentally (11).  
Plastics waste burning is not an effective solution to solve  
plastics accumulation problems. That process releases toxic  
gases into the environment including dioxins, heavy metals,  
PCBs, and furans causing various respiratory system diseases  
(
(
14, 15), and to stop plastics polluting the land, air, and water  
10).  
2
Type of Plastics  
Plastics generally divided into two categories,  
thermoplastics and thermosets. Thermoplastics are a group of  
plastics that can be melted when heated and hardened when  
cooled.  
Thermoplastics  
are  
including  
Polyethylene  
Terephthalate (PET), Polyethylene (PE), Low-Density  
Polyethylene (LDPE), High-Density Polyethylene (HDPE),  
Polystyrene (PS), Expanded polystyrene (EPS), Polyvinyl-  
chloride (PVC), Polycarbonate, Polypropylene (PP), Polylactic  
acid (PLA) and Polyhydroxyalkanoates (PHA). Meanwhile,  
thermosets are plastics which their chemical structures can be  
changed when heated thus can not be re-melted. Thermoset  
plastics are including Polyurethane (PUR), Phenolic resins,  
Epoxy resins, Silicone, Vinyl ester, Acrylic resins,  
Ureaformaldehyde (UF) resins (4).  
Polyethylene terephthalate (PET) is a transparent and thin  
plastic that commonly used as a wrapper for various foods and  
drinks. Low-density polyethylene (LDPE) is a flexible and  
strong heat-resistant plastic usually used as a drink container.  
High-density polyethylene (HDPE), made from heat-resistant  
petroleum, is commonly used as plastic bags. While Polyvinyl  
chloride (PVC) is a synthetic plastic containing many chemical  
additives such as heavy metals, dioxins, BPA, and phthalates  
resulting in various health problems as bronchitis and cancer.  
This plastic is widely used as a wrapper, such as vegetable oil  
wrapper. Polypropylene (PP), strong and semi-permanent  
plastic, commonly used for medicine packaging. Polystyrene  
2
(23, 18). Furthermore, the plastic burning produces CO into the  
air, the gas is related to global warming. It will trap solar heat  
that increases the earth's surface temperature (24, 18).  
(
PS) is a petroleum-based plastic that contains benzene, a  
The accumulated plastics waste on the land is hard to  
degrade. It will inhibit the water infiltration into the soil (11),  
leads to soil infertility. The plastics waste accumulation on the  
land reduces the availability of oxygen in the soil. The amount  
of plastics waste in the soil causes the reduction of soil-  
decomposing organisms, thus decomposition of organic and  
inorganic materials will be decreased that affects the soil fertility  
and inhibits plant growth (22).  
carcinogenic compound. This plastic widely used as cutleries.  
Polycarbonate is a plastic that contains hazardous BPA material,  
this plastic is usually used as a reusable bottle (17, 18).  
Meanwhile, the most common single-use plastics are LDPE,  
HDPE, PET, PS, EPS, and PP (4).  
Based on Plastic Europe 2018, In Europe, the highest plastic  
demands are LDPE, HDPE, polypropylene, polyvinyl chloride,  
polyurethane, polystyrene, and polyethylene terephthalate. The  
need for LDPE is 17.5% and HDPE 12.3%. While the need for  
polypropylene is 19.3%, polyvinyl chloride 10.2%, polyurethane  
4
Plastics Hazardous Substances  
Plastics contain some hazardous substances affecting human  
7
(
.7%, polystyrene 7.4%, and polyethylene terephthalate is 7.4%  
19).  
In addition to nonbiodegradable synthetic plastics,  
health. Dangerous plastic components such as bisphenol A  
found in PC and PVC can cause the reproductive system  
disorders, mainly the ovaries. Phthalates contained in PS and  
PVC lead to testosterone disorders and interfere with sperm  
motility. The styrene monomers as those found in polystyrene-  
type plastics are carcinogenic. Nonylphenol contained in PVC  
causes estrogen disorders. Meanwhile, dioxins, persistent  
organic pollutants (POPs), polycyclic aromatic hydrocarbons  
biodegradable plastics are now being developed and used.  
Biodegradable plastics and polymers are materials that are now  
widely used in various industries. The use of biodegradable  
plastics is related to environmental problems due to the  
recalcitrant characteristic of petroleum-based plastics waste.  
Some biodegradable plastics are polylactic acid (PLA) and  
polybutylene adipate-co-terephthalate (20, 21). Although PLA is  
biodegradable, the polymer still requires a long time to be  
degraded in nature. The complete biodegradation process of a  
biodegradable polymer in nature takes months or even years  
(
PAHs), and polychlorinated biphenyls (PCBs) found in almost  
all plastic types resulting in various health problems. Dioxins are  
carcinogens interfering with testosterone disorders. POPs can  
disrupt the nervous and reproductive systems. PAHs associated  
with the reproductive system and development disorders, and  
PCBs related to thyroid hormone disorders (25, 18).  
(
21).  
149  
Journal of Environmental Treatment Techniques  
2021, Volume 9, Issue 1, Pages: 148-157  
kinds of acid compounds changing the pH of plastic polymers  
leads to chemical plastic deterioration causing changes of the  
polymer microstructures. These acids are including nitrous acid,  
nitric acid or sulfuric acid, citric, fumaric, gluconic, glutaric,  
glyoxylic, oxalic, and oxaloacetic (32). The plastic surface  
damages associated with metabolites and extracellular enzymes  
released by bacteria (34).  
Depolymerization of the plastic constituents is carried out by  
depolymerase enzymes. The results of this reaction can be in the  
form of oligomers, dimers, and monomers that are simpler than  
polymers. They will be further processed according to the  
presence of oxygen molecules in metabolism. Aerobic  
degradation of those components will produce microbial  
5
General Plastics Waste Management  
Plastics waste landfill and incineration are two commonly  
used plastic waste management methods. However, these two  
methods are considered as the managing plastic waste processes  
which have side effects on the environment as they release  
various toxic gases into the air, besides landfill also requires a  
large space. Plastics recycling activities are also relatively  
ineffective in dealing with the abundance of plastic waste (13).  
The application of reuse, reduce, and recycle is now widely  
promoted in addition to solve plastic waste problems. It is  
appropriate for postindustrial plastics, yet it is not effective for  
plastics that have been used or consumed by people that are  
usually mixed with other organic and inorganic wastes.  
Afterward, chemical methods of plastics waste management  
systems are influenced by several factors and conditions related  
to the polymer constituents of each plastic (8).  
biomass, CO  
change those components into microbial biomass, CO  
and CH or H S (35).  
2
, and H  
2
O. While anaerobic degradation will  
2
, H O,  
2
4
2
Extracellular and intracellular depolymerase enzymes  
secreted by microbes have important roles in plastic waste  
degradation. During the degradation process, the released  
enzymes will break down complex polymers into smaller and  
simpler chains. These decomposed small molecules will be  
easily dissolved in water then absorbed through microbial  
semipermeable cell membranes to be used as carbon and energy  
sources. Assimilation occurs in microbial cytoplasms in which  
the metabolic process occurs to produce energy, biomass, food  
reserves, primary and secondary metabolites (29). After  
degraded into smaller ones, plastic fragments such as monomers  
will enter the cells. These components enter the microbial cell  
metabolism system to undergo a subsequent degradation process  
to form energy and biomass for microorganisms. Even though  
monomers have formed, sometimes they do not fully  
assimilated. They will be released outside of the cells and will  
be used by other microorganisms that have a suitable  
assimilation pathway for those monomers (32).  
The next process of biodegradation is mineralization.  
Mineralization is the final metabolic process of plastic waste  
toxic compounds. This process changes those hazardous  
compounds into more environmentally safe compounds (36).  
Mineralization is a process of converting biodegradable  
materials or biomass into gases, water, salt, minerals, and other  
residues. The formed gases include carbon dioxide, methane,  
and nitrogen components. The mineralization process will be  
ended when all biodegradable compounds have been consumed  
by microorganisms and all carbons are converted to carbon  
dioxide (37, 38).  
6
Plastics Biodegradation  
A plastics waste processing effective method is needed (14,  
1
5) to balance the increasing uses of plastics every year (26). It  
is Biodegradation. Biodegradation is an effective, profitable, and  
economically valuable plastics waste processing method. The  
ability of many microorganisms to break down plastic polymers  
is an advantage that can be used in dealing with problems arising  
from the increasing accumulation of plastics waste every day.  
Some microorganisms produce various kinds of enzymes, both  
intracellular and extracellular, catalyze plastic polymers  
degradation into safe smaller fragments (14, 15). The utilization  
of microbial cells directly to degrade plastic C-C bonds is  
considered more effective (27). Biodegradation is a specific  
enzymatic process. Certain enzymes break down certain  
substrates (28).  
The plastic waste biodegradation process occurs through  
several stages, including biodeterioration, depolymerization, and  
assimilation. Biodeterioration is a cooperation between several  
microbes and abiotic factors that breaks down polymers into  
smaller ones. This process will be continued with  
depolymerization. Depolymerization occurs in which microbes  
secrete catalytic compounds in the form of enzymes and free  
radicals to form biofilms helping them to break the polymer  
chains progressively (29).  
Biodeterioration is a process of changing or modifying  
plastic polymers carried out by some microorganisms on the  
plastic surface. The changes include chemical, physical, and  
mechanical changes (30). This process will be accelerated by  
biofilms formed by microorganisms on the plastic surface. A  
biofilm is a form of living things community. Microbes attach  
themselves and colonize the surface of an object to form  
biofilms assisted by an extracellular compound produced by  
them. In the form of biofilms, microbial cells attach one to  
another in a polymer matrix containing polysaccharides and  
proteins (13). Extracellular polymeric substances (EPS)  
produced by microorganisms help them to break down the  
plastic surface (31, 32). EPS consists of polysaccharides,  
proteins, and nucleic acids (33).  
7
Plastics Degrading Bacteria  
Many plastics degrading bacteria have been widely reported  
by researchers as compiled in table 1. Some of PE degrading  
bacteria are including D.nigrificans and Pseudomonas  
alcaligenes isolated from plastic waste contaminated soil  
16), Enterobacter sp. D1 isolated from the guts of Galleria  
(
mellonella (39) and P.putida MTCC 2475 isolated from garden  
soil. P.putida MTCC 2475 reduced milk cover weight about  
63.1  
73.3% within  
1
month incubation (40). In  
the Enterobacter sp. D1 treated solution there was increasing of  
alcohol, esters, acidic compounds, ethyl decanoate, and 6-  
methyl-5-hepten-2-ol. Alcohol, alkaline, hydrocarbon, esters,  
and acid compounds indicate bacterial metabolism in degrading  
PE (41, 39). That process involves various oxidoreductase  
enzymes (39).  
EPS penetrates the plastic surface pores causing enlargement  
of the pores. It is enhanced microbes, bacteria, to damage plastic  
polymers, to form holes, and to encourage the physical  
deterioration of plastic polymers (31, 32). Also, the formation of  
biofilms on plastic surfaces encourages the formation of various  
150  
Journal of Environmental Treatment Techniques  
2021, Volume 9, Issue 1, Pages: 148-157  
Tabel 1: Plastics Degrading Bacteria  
Observation of  
Media  
Plastic  
Types  
Incubation  
References  
Time  
Bacteria  
Isolate Sources  
Garbage Soil  
Degradation  
32% of PWL  
14% of PWL  
Bacillus  
Culture Broth Medium  
Culture Broth Medium  
Nutrient Broth  
1 Month  
1 Month  
1 Month  
(42)  
(42)  
(16)  
amylolyticus  
Bacillus subtilis  
Desulfotomaculu  
m nigrifans  
Enterobacter sp.  
D1  
Pseudomonas  
alcaligenes  
Pseudomonas  
fluorescens  
Pseudomonas  
putida  
Garbage Soil  
Plastic Contaminated  
Soil  
Isolated from Gut of  
Galleria mellonella  
Plastic Contaminated  
Soil  
1
6.2% of PWL  
1.98% of CD  
1.98% of OI  
A Carbon-Free Source  
Agar Solid Medium  
3
1 Days  
(39)  
(16)  
(42)  
(42)  
1
6.2% of PWL  
Nutrient Broth  
1 Month  
1 Month  
1 Month  
Garbage Soil  
Garbage Soil  
22% of PWL  
18% of PWL  
Culture Broth Medium  
Culture Broth Medium  
PE  
Pseudomonas  
putida MTCC  
Garden Soil  
>10% of PWL  
Mineral Salt Medium  
1 Month  
(40)  
2
475  
Streptomyces  
SSP2  
Streptomyces  
SSP4  
Sterptomyces  
SSP14  
Actinobacter  
ursingii  
Soil  
8% of PWL  
ATCC Medium  
ATCC Medium  
ATCC Medium  
Solid MSM  
1 Month  
1 Month  
1 Month  
3 Days  
(12)  
(12)  
(12)  
(48)  
Soil  
11% of PWL  
Soil  
19% of PWL  
Soil and Plastic Waste  
Color Zone on the Medium  
Alcanivorax  
borkumensis  
Marine Plastic Waste  
Sedimentations  
Liquid Medium Containing  
0.05% Hexadecane  
3
.5% of PWL  
80 Days  
(50)  
Bacillus  
carbonipphilus  
25% of PWL  
Mineral Broth  
Mineral Agar  
LDPE Contaminated  
Soil  
2 Months  
(45)  
(45)  
(49)  
34.55% of PWL  
Bacillus  
coagulans  
Bacillus  
licheniformis  
KC2-MRL  
Bacillus  
LDPE Contaminated  
Soil  
16% of PWL  
18.37% of PWL  
Mineral Broth  
Mineral Agar  
2
Months  
Soil  
Plastic’s Surface Damage  
Mineral Salt Medium  
1 Month  
2 Months  
2 Months  
2 Months  
LDPE Contaminated  
Soil  
LDPE Contaminated  
Soil  
LDPE Contaminated  
Soil  
34.48% of PWL  
21% of PWL  
36.07% of PWL  
14% of PWL  
16.40% of PWL  
8% of PWL  
Mineral Agar  
Mineral Broth  
Mineral Agar  
Mineral Broth  
Mineral Agar  
Mineral Broth  
(45)  
(45)  
(45)  
megaterium  
Bacillus nedei  
Bacillus smithii  
Bacillus sp. KC3-  
MRL  
Bacillus  
sporothermo-  
durans  
Soil  
Plastic Surface Damage  
36.54% of PWL  
21% of PWL  
Mineral Salt Medium  
Mineral Agar  
1 Month  
(49)  
(45)  
LDPE  
LDPE Contaminated  
Soil  
2 Months  
Mineral Broth  
Bacillus  
weihenstephanens  
is  
Hydrocarbon enriched  
soil  
32.61% of TPBWL and  
35.64% of ThPBWL  
C-zopek-Dox Broth  
6 Months  
(82)  
Burkholderia  
cepacia  
Hydrocarbon Enriched  
Soil  
31.43% of TPBWL and  
36.34% of ThPBWL  
C-zopek-Dox Broth  
C-zopek-Dox Broth  
6 Months  
6 Months  
(82)  
(82)  
Hydrocarbon Enriched  
Soil  
23.27% of TPBWL and  
23.57% of ThPBWL  
Escherichia coli  
Pseudomonas  
aeruginosa  
Pseudomonas  
fluorescens  
Serratia sp. KCI-  
MRL  
Stenotropphomon  
as sp. KC4-MRL  
Streptomyces  
coelicoflavus  
Landfill Soil  
Garbage Soil  
Soil  
18.75% of PWL  
Mineral Salt Broth  
45 Days  
1 Month  
1 Month  
1 Month  
4 weeks  
(47)  
(42)  
(49)  
(49)  
(51)  
22% of PWL  
Culture Broth Medium  
Mineral Salt Medium  
Mineral Salt Medium  
Mineralt Salt Agar  
Plastic Surface Damage  
Plastic Surface Damage  
30% of PWL  
Soil  
Oil Contaminated Soil  
151  
Journal of Environmental Treatment Techniques  
2021, Volume 9, Issue 1, Pages: 148-157  
Plastic  
Types  
Observation of  
Degradation  
Incubation  
References  
Time  
Bacteria  
Isolate Sources  
Media  
NBRC 15399T  
Streptomyces  
SSP2  
Streptomyces  
SSP4  
Sterptomyces  
SSP14  
Ochrobacterum  
anthropi  
Soil  
6% of PWL  
9% of PWL  
17% of PWL  
20% of PWL  
12% of PWL  
11% of PWL  
ATCC Medium  
ATCC Medium  
ATCC Medium  
Mineral Salt Broth  
Mineral Broth  
1 Month  
1 Bulan  
1 Month  
45 Days  
40 Days  
40 Days  
(12)  
(12)  
(12)  
(47)  
(53)  
(53)  
Soil  
Soil  
HDPE  
PP  
Landfill Soil  
Mangrove sediment  
Mangrove sediment  
Bacillus cereus  
Sporosacrina  
globispora  
Mineral Broth  
2
5
0% of PWL in NB and  
8.82% of PWL in BHB  
Bacillus subtilis