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A Preliminary Study on the Potential Biodegrading Ability POSTer draft

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					                       A Preliminary Study on the Potential Biodegrading Ability of Xylaria sp.
                            on Natural Rubber, Chicken Feather and Polystyrene through
                                           Scanning Electron Microscopy
                                                                                  Janine Erica P. Dayao1 and Mary Bernadette V. Egloso1,
                                                                                      Anna Theresa A. Santiago1 and Mary Ann T. Tavanlar2
                                                       1Department  of Biology, College of Arts and Sciences, University of the Philippines Manila, Padre Faura St., Ermita, Manila
                                                       2National Institute of Molecular Biology and Biotechnology, University of the Philippines Los Baños, College Laguna 4031


  ABSTRACT                                                                                                                                                                            CHICKEN
The potential biodegrading ability of the Xylaria sp. strains on three pollutants, namely, natural rubber, chicken feather and polystyrene
                                                                                                                                                                                      FEATHER
were determined in terms of colonization. The fungal strains namely the wild type, SDM (sterile dark mycelia) and the five mutant
strains (PNL 114, PNL 116, PNL 118, E26 and E35) were cultured in a pH 5.0 mineral medium with 0.5% glucose as carbon source,
while the 3 pollutant substrates as co-carbon source, and stored at 250C. The initial weights of the pollutants were measured before
inoculation. After 50 days of incubation, the pollutants were removed from the medium and weights were again measured to determine
percent weight loss, a method that would measure utilization of the pollutant samples. But instead of constant weight loss, weight
gains resulted, which could be attributed to the adherence and penetration of mycelia of the Xylaria sp. strains in the three pollutant
substrates. Scanning Electron Microscopy (SEM) revealed colonization of Xylaria sp. strain on natural rubber, chicken feather and
polystyrene. Generally, the black strains, namely the SDM wild type, E26 and E35, have been observed to possess a higher potential to
biodegrade natural rubber, chicken feather and polystyrene than the albino mutants PNL 114, 116 and 118. The black variant strain E26
has shown the most potential for biodegrading natural rubber, followed by the albino mutants. Among the black variant strains, E26
has shown the greatest biodegrading potential for natural rubber, nonetheless the albino mutants also showed potential to biodegrade
this substrate. Polystyrene was effectively colonized by the three black strains SDM wild type, E26 and E35, nonetheless the albino
mutants also showed potential ability to biodegrade this substrate. Chicken feathers were colonized by the SDM and E35 but may
require a longer incubation period for degradation.’

 INTRODUCTIION                                             METHODOLOGY




   RESULTS
                                                          NATURAL
                                                          RUBBER




                                                                                                                                  LEGEND:

                                                                                                                                  my=mycelia

                                                                                                                                  hy=hypha

                                                                                                                                  sp=spores                                                All strains efficiently colonized the samples, but
                                                                                                                                                                                           only SDM and E35 showed signs of degradation
                                                                                                                                                                                           such as weakened barbs and slightly brittle
                                                                                                                                  st=striation                                             barbules which detached from their barbs.

                                                                                                                                  tr=tearing

                                                                                                                                  c=crack                                         POLYSTYRENE

                                                                                                                                  r=rachis

                                                                                                                                  br=barb

                                                                                                                                  bl=barbule

                                                                                                                                  p=residual
                                                                                                                                  polystyrene

                                                                                                                                  mc=mycelia




                                                                    Generally, the black strains specially strain E26,
                                                                    showed the greatest biodegrading potential as
                                                                    compared to the albino strains PNL 114, 116 and
                                                                    118.



   DISCUSSION
Natural rubber, polystyrene and chicken feather were utilized as co-substrates of glucose for the growth of Xylaria sp. Mycelia closely adhered to their
surface and grew into it, thereby rendering their removal very difficult. Due to this, the change in weight was not measured. Thus, weight gain is
indicative of colonization, whereas weight loss is indicative of biodegradation. The 0.5% glucose provided in the medium initiated (Cuevas &
Manaligod, 1997; Clutario & Cuevas, 2001) and sustained growth for up to 3 weeks (M. A. Tavanlar, personal communication, March 4, 2009). Beyond
this period when glucose has been depleted, Xylaria sp. had to utilize the provided substrate as an alternative carbon source. After incubation, the
set-ups were covered by mycelia. Such colonization and surface adhesion is a fundamental prerequisite to biodegradation, although growth on a
polymer surface is not adequate to deduce that carbon from this polymer has been assimilated. Nonetheless, this colonization provides a simple, fast
and clear test to evaluate the response of a macromolecular material to biodegradation (Clutario & Cuevas, 2001; Motta,et al., 2007). Gentle scraping
was done after removal of fungi from the samples to avoid surface destruction and to further remove mycelia. Hence, the colonization seen under SEM
cannot be attributed to mere mycelial aggregation on the surface since physical manipulation was done. Most samples were covered by a slimy
mucilaginous sheath or biofilm which can be easily removed. All strains tested in this study are able to form biofilm (M. A. Tavanlar, personal
communication, March 4, 2009), which is a crucial step to microbially induced biodegradation. A study (Reddy, et al., 1982; Gutnick & Minas, 1987)                                        Polystyrene was the most extensively colonized
hypothesized that after adhesion, solubilizing agents are secreted by microorganisms which can make use of water-immiscible compounds (Clutario &                                         substrate. SEM results of the albino mutants
Cuevas, 2001). The denser and thicker mycelial growth and more efficient performance of the black strains SDM wild type, E26 and E35 than the                                             were not widely different from the black strains.
albino mutants (PNL 114, 116 and 118) is due to the melanin cover of their hyphal surfaces. Melanin protects their hyphae thus making them
resistant to frictional damage during penetration into the substrate. The pollutants were weakened in resistance and durability due to mycelial
penetration.
                                                                                                                                                           ACKNOWLEDGMENT
  CONCLUSION
                NATURAL                           CHICKEN
                              POLYSTYRENE
                RUBBER                            FEATHER




                   AGITATION w/ EtOH and                       SURFACE
                                               AUTOCLAVE
                       STERILE WATER                        STERILIZATION

SDM Wild type
  PNL 114
  PNL 116
                 XYLARIA        MINERAL MEDIUM
  PNL 118
                SP. STRAIN        w/ GLUCOSE
                                                      FUNGAL INOCULATION
    E26
    E35

                                    50 DAY
                                  INCUBATION



                                DECANT & GENTLE     CLEANING OF SUBSTRATE
                                   SCRAPING              OF MYCELIA


                              SCANNING ELECTRON
                                 MICROSCOPY