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Executive Summary
Isolation & Identification of LDPE Degrading Bacteria from Landfill Soil. The aim of this study was to isolate the bacteria from the soil of landfill and to evaluate microbial degradation of the sheet of low-density polythene (LDPE). To find the microbes that can degrade polythene, samples were collected from Amin bazar landfill soil, Dhaka.
Screening of polythene degrading bacteria was performed by analyzing the growth in Low Density Polyethylene (LDPE) powder. Eight potential bacterial isolates were obtained using mineral salt media containing LDPE powder as sole carbon source. Low-density polyethylene (LDPE) poses environmental challenges due to its non-biodegradable nature.
The Gram staining test revealed all the isolates were Gram positive. The dry cell weight (g/100 L) was measured at 0.1% concentrations of LDPE powder; the biomass was increased for all the bacterial isolates. Isolates 2 and 7 had the highest cell weight values of 0.9 g and 0.8 g, respectively. The weight loss in LDPE sheet by isolate strain 3 and strain 2 was 41% and 33%, respectively. Thus, the potential isolates could be used as LDPE degrading bacteria.
Background of the Study
The term plastic is derived from the Greek word “plastikos‟ which means “capable of being shaped or molded”. Organic and inorganic raw materials such as carbon, silicon, hydrogen, nitrogen oxygen and chloride are used for the manufacture of plastic and are in use today. Plasticity is the property of any material by which the material can irreversibly deform without breaking. A polymer is a macromolecule composed of repeating structural units connected by covalent bonds. Examples of polymers include plastics, starch, and proteins.
In 1988, the Society of the Plastics Industry introduced the Resin Identification Code (RIC) system which divided plastic resins into 7 different categories (Such as: PET, HDPE, LDPE, PP, PS, PVC, and others. The first low density polyethylene (LDPE) was created using the high-pressure polymerization of ethylene.
| Report Title : | Isolation & Identification of LDPE-Degrading Bacteria from Landfill Soil. |
| University Name : | Bangladesh University of Professionals |
| Submitted To : | Dr. Tabassum Mumtaz |
| Submitted By : | Sun Jarin Juthi |
| Total Page : | 91 |
low density is due to the existence of a modest degree of branching in the chain (on around 2% of the carbon atoms). Low-density polyethylene (LDPE) presents a significant environmental challenge due to its non-biodegradable nature and widespread use. LDPE products, such as plastic bags, transportation, food, clothes, medicine, recreation, fishing nets, packaging, and the food industry contribute significantly to plastic pollution.
The aim of this research was to study the biodegradation of low-density polyethylene using various techniques in vitro by selected and potent microorganism isolated from municipal solid waste.
Problem Statement
This massive amount of plastic is still floating in the water and may be seen on top of and underneath the earth. It’s become a serious issue because of the harm it does to people, wildlife, and their habitats. There are a variety of ways in which plastic trash harms ecosystems. Because plastics stay so long in the ecosystem, it pollutes, takes up space, and contaminates habitats.
All the trash that didn’t get recycled became a hazard for marine life. The ocean is littered with trash. When marine organisms ingest it, it’s a happy accident. This plastic has a negative impact on their health. Micro plastics, for instance, have been detected in the organs of marine mammals, including the liver, the stomach, and the kidneys.
Outline of the Report
Introduction part
Background of the study, Problem statement, Rationale of the study, Research questions, Objectives of the study, Research gap, Limitations of the study.
Literature review Part:
Plastics, Types of plastics, Brief history of LDPE, Environmental contamination by LDPE, Soil contamination by LDPE, Water pollution by LDPE, Air pollution by LDPE, Effects on public health, Biodegradation of LDPE, Biodegradation by bacteria, Biodegradation by fungi, Mechanism of microbial degradation.
Methodology Part:
Materials, Area of Study/Sampling site, Sample collection, Methods, Instruments, Sterilization of glassware and media, Mineral media preparation, LDPE powder preparation, Isolation and maintenance of microbes, Stock solution preparation, Enumeration by serial dilution technique,
Plate preparation and inoculation, Isolation of bacterial colony, Pure culture preparation, Characterization of bacteria, Colony morphology, Gram staining, Biochemical tests, Indole production test, Methyl Red (MR) test, Voges- Proskauer test, Citrate utilization test, Catalase test, Oxidase test, Utilization of LDPE as sole carbon source in shake flask, Optical density measurement,
Dry cell weight measurement, LDPE degradation experiment using LDPE sheet in MSM broth, Polyethylene sample preparation, Incubation of bacteria with treated polyethylene.
Data analysis Part:
Measurement of optical density, Determination of cell weight, Determination of weight loss.
Result and discussion Part:
Isolation of LDPE degrading microbes, Determination of morphological and biochemical characteristics, Determination of LDPE degradation efficacy of the isolated bacterial strains, Weight loss of LDPE by isolated strain, Major findings, Discussion.
Research Objectives
Broad objective
To Isolate and characterize the low-density polyethylene (LDPE) degrading soil bacteria from plastic contaminated soil.
Specific objectives
- To isolate the potential bacteria which can degrade LDPE?
- To determine the morphological and biochemical characteristics of potential bacteria.
- To determine plastic degradation efficacy of soil bacteria, present in plastic contaminated site.
- To determine the weight loss of LDPE sheet by potential isolated bacterial strains.
Research Questions
Research questions
- Is the soil microbe potential to degrade the plastic substances in plastic contaminated soil in Bangladesh?
- Which plastic degrader species are abundant in such contaminated soil?
- Which are the most efficient plastic degraders among all the microorganisms in the collected samples?
Conclusion
In this study, chosen bacterial strains demonstrated amazing capability in digesting polyethylene, providing a long-term solution to environmental harm. This study can help decreasing the environmental impact of polyethylene accumulation, protecting ecosystems, and paving the way for a cleaner, greener future by developing interdisciplinary cooperation and investing in breakthrough biotechnological solutions.
