Pseudomonas putida

Low density polythene (LDPE) is the most widely used packaging material primarily because of its excellent mechanical properties, barrier properties against water, light weight, low cost and high energy effectiveness.
LDPE to biological attack was believed to be contributed by the hydrophobic carbon backbone and high molecular weight of the polymer. Thus, over the years, the rapid biodegradation of plastic has been a subject of interest in the waste management problem.
Each year, an estimated 500 billion to 1 trillion plastic bags are consumed worldwide. After their use, these packaging materials are dumped in landfills leading to pollution since they are non-biodegradable under natural environmental conditions

1. Presentation Topic : Biodegradation Of Plastic By Pseudomonas putida P resented by , Miss A MRITHA S R BSc B IOTECHNOLOGY F ACULTY OF LIFE SCIENCES J AGADGURU SRI SHIVARATHREESHWARA ACADEMY OF HIGHER EDUCATION AND RESEARCH MYSURU 1 4 th May 2019

2. Overview Introduction Pseudomonas putida Steps involved in degradation Disadvantages Current research Conclusions 2

3. INTRODUCTION Low density polythene (LDPE) is the most widely used packaging material primarily because of its excellent mechanical properties, barrier properties against water, light weight, low cost and high energy effectiveness. LDPE to biological attack was believed to be contributed by the hydrophobic carbon backbone and high molecular weight of the polymer. Thus, over the years, the rapid biodegradation of plastic has been a subject of interest in the waste management problem. Each year, an estimated 500 billion to 1 trillion plastic bags are consumed worldwide. After their use, these packaging materials are dumped in landfills leading to pollution since they are non-biodegradable under natural environmental conditions 3

4. PSEUDOMONAS PUTIDA Pseudomonas putida  is a gram-negative, rod-shaped bacteria which undergoes aerobic metabolism . It is normally found in terrestrial and aquatic environments where oxygen is abundant.  P.putida  is well known for being one of the most metabolically diverse organisms capable of breaking down both natural organic molecules as well as industrial compounds such as toluene and styrene. 4

5. Steps involved in degradation Bio-deterioration  defines the action of microbial communities and other decomposer organisms responsible for the physical and chemical deterioration that resulted in a superficial degradation that modifies the mechanical, physical and chemical properties of the plastic. Bio-fragmentation  refers to the catalytic actions that cleave polymeric plastics into oligomers, dimers or monomers by ecto -enzymes or free-radicals secreted by microorganisms. Assimilation   characterizes to the integration of molecules transported in the cytoplasm in the microbial metabolism. Mineralisation  refers to the complete degradation of molecules that resulted in the excretion of completely oxidized metabolites (CO 2 , N 2 , CH 4 , H 2 O). 5

6. Factors explored for a better biodegradation of polymer plastics (i) by using surface active agents or inducing the microorganism to produce surfactant to allow better attachment of microorganisms on the polymer surface , (ii) by blending the polymers with biodegradable synthetic polymers such as polylactic acid or polycaprolactum ( iii ) by culturing those microorganisms that can efficiently degrade the plastics (bio-addition) and (iv ) by addition of nutrients that may be limiting in the environment (bio-stimulation). 6

7. Disadvantages A 2005 research article stated that Pseudomonas putida is associated with clinical infections in pre-mature babies. Babies that were admitted into Special Care Nursery (SCN) were fed through catheters. These catheters went through a heparin flush procedure in order to keep the pathway clear for fluids to enter the body. During this procedure, the environment conditions within the tube allowed P. putida to grow. This growth of bacteria caused bloodstream infections within the baby. Although heparin has antibiotic activity , P. putida is resistant and is able to grow. 7

8. Current Research In a recent study,  Pseudomonas putida  strains were compared to each other to determine the phylogenetic relationships. Because the  Pseudomonas putida  strain KT2440 genome is fully sequenced it serves as a standard reference to compare with other  Pseudomonas putida  strains. They carried out a study that assessed the utility of  Pseudomonas putida  strain KT2440-based high-density DNA microrarrays for transcriptomics studies of DSM 6125, DSM 3931, DSM 291, and S12, along with other non-sequenced strains. 8

9. Concluding remarks and perspectives For the last 30 years, scientists are trying to develop some alternative ways where they can use microbes to degrade these long chain synthetic polymers into their respective monomers. Until now, very few evidences are available where scientists were able to develop some alternative ways to enhance the mode of degradation and make it faster. Nature-like experiments are difficult to realize in laboratory due to the great number of parameters occurring during the biogeochemical recycling . To date, most of the knowledge on the microbial ability to degrade synthetic plastics is based on few bacteria able to grow on culture media, that represent <0.1% of the total bacteria . Hence, the great natural source of high diversity of microorganisms is not fully exploited. By using - omics technologies (genomic, transcriptomic , proteomic, metabolomics), it is now possible to discover new non- culturable microorganisms involved in plastic colonization and degradation, and explore the new properties of microorganisms that arise from the interplay of genes, proteins, other macromolecules, small molecules, and the environment. 9

10. Citations https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3460136 / https://oceans.taraexpeditions.org/en/m/science/news/bacterial-degradation-of-synthetic-plastics / 10

11. 11 Thank you