I am E.K. Ramya, working as a Project Assistant under the foldscope project of DBT. Our PI is Dr.  S. Sharmila, Assistant Professor, Vellalar College for Women, Erode, Tamil nadu.

  • Litter decomposition is a process of decaying the dead organic material – with the help of microorganisms. It is one of the crucial role in the forest ecosystem.
  • For decomposition Bacteria and Fungi play a major role.
  • Identification of litter decomposing microorganisms in study area was the 4th step of my study. For this study, I have collected the litter samples in litter bags during May 2018 and the collected samples are used for further microbial analysis.

Analysis of microbes from litter (May 2018):

Litter sample contains mass of microorganisms. It was isolated in the culture medium using Nutrient Agar Medium.

For isolation I have followed 4 important steps:

Step 1: Bacterial Colony formation

Step 2: Isolation of bacteria in Pure culture

Step 3: Gram staining

Step 4: Biochemical test

Step 1: Bacterial Colony formation:

  • Bacteria grow on solid media as colonies.
  • A colony is known as visible mass of microorganisms originating from single mother cell.
This pic… shows the Nutrient Agar Media with Beautiful Bacterial Colonies
  • The plate showing the bacterial colonies. I have captured this picture in my microbial laboratory. The pic… also indicates numerous different colonies.
  • The Colonies are occurring in different size & shape. I have calculated number of colonies in single plate with the help of colony counter.

Step 2: Isolation of bacteria in Pure culture:

  • Different bacterial colonies were isolated and inoculated into other separate media.
  • After 4 or 5 sub culturing I have maintained two pure cultures.
This pic… shows the unknown bacteria in Nutrient Agar Media – Quadrant Streak plating
  • For separation of gram positive and gram negative I have done Staining process. With the support of foldscope under high magnification I clearly viewed beautiful colour differentiation in gram staining process.

Two pure cultures:

  1. Gram positive
  2. Gram negative
Foldscope view of Rod shaped Gram-positive bacteria– (violet)
Foldscope view of Rod shaped Gram-negative bacteria – (Pink)

Biochemical test:

This is the important step for differentiate species from genera.

Biochemical Test for Gram- Positive bacteria

  1. Indole test
  2. Methyl Red test
  3. Vioges Proskauer test
  4. Citrate utilization test

                                                               Indole test (-ve)

                            a) No pink ring formation

                                                                  Methyl Red test (-ve)

                                 b) No colour changes (pink)

            Vioges Proskauer test (+ve)

                                        c) Pink ring formation

           Citrate utilization test (+ve)

                                        d) Colour changes (Blue)
  1. Biochemical Test for Gram- Negative bacteria

Indoletest (-ve)

                                  e) No pink ring formation

                                                               Methyl Red test (-ve)

                                     f) No colour changes (pink)

                Vioges Proskauer test(-ve)

                                     g) No pink ring formation

Citrate utilization test (+ve)

                          h) Colour changes (Dark blue)


As per the schedule of work plan, half of the work in process. Later I will upload remaining part of the study (Isolation of micro – organisms) with the help of foldscope magnification.

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