POLLUTION IN THE PHILIPPINES
A Filipino generates around 0.3 to 0.7 kilograms of garbage daily depending on income levels,
according to a study1 by the World Bank. Metro Manila produces about 8,000 tons of solid waste each
day and is expected to reach 13,300 tons in 2014 (Baroña, 2004). The National Capital Region produces
the highest amount of wastes, about 23% of the country’s waste generation (www.asria.org). According
to a discards survey conducted by the EcoWaste Coalition and Greenpeace Southeast Asia in 2006,
synthetic plastics comprise the 76% of the floating trash in Manila Bay, out of which 51% are plastic
bags, 19% are sachets and junk food wrappers, 5% are styrofoams and 1% of hard plastics. The rest
were rubber 10% and biodegradable discards 13% (EcoWaste Coalition, 2008).
World Bank. The Philippines Environment Monitor 2001. (Pasig City: Philippines: World Bank, December
BIOREMEDIATION / BIODEGRADATION
Bioremediation is the process wherein biological systems such as plants,
microorganisms, and fungi are used to reduce pollution. They break down pollutants for their
growth and/or energy needs. In co-metabolism, some organisms use metabolic pathways for
their growth and energy supply while at the same time, breaking down pollutant molecules.
This concept is utilized by researchers for further bioremediation purposes. The products of a
complete biodegradation include carbon dioxide, water, and harmless inorganic salts.
Incomplete biodegradation, on the other hand, may produce breakdown substances which may
or may not be more toxic or harmful than the original pollutant.
In many cases, conditions are not favorable enough to promote spontaneous
biodegradation or natural attenuation. There is a further need to add nutrients or suitable
organisms for biodegradation to occur, due to their insufficient quantity. The future trend
would be to discern first the speed of unaided biodegradation, before adding any supplements,
and then act only if there is insufficient activity which is fast enough to remove the contaminant
before causing any expected risks.
The fungal isolate, which will be used in this study was discovered by Cuevas and
Manaligods (1997). They found it growing on a sando plastic bag buried in forest soil and litter
in the lowland secondary forest of Mt. Makiling, Laguna. The fungus comprised of sterile
melanin pigmented mycelia. Initially it was reported as ascomycete sterile dark mycelia (ASDM),
but further cultural studies have shown that it belongs to the Class Ascomycete, Order
Xylariales, under the genus Xylaria (unpublished data). This genus has the following
characteristics (Rogers et al., 2000) :
Characteristics of the Xylaria sp.
stromatal tissue quantity: distributed above, around, and beneath
stromatal layers: unipartite
stromatal surface level: erumpent or superficial
stromatal interior: essentially homogeneous
stromatal orange granules surrounding perithecia: absent
stromatal KOH pigments: absent
stromatal conidium-bearing discs: absent
stromatal bases: stipitate or, if sessile, conspicuously constricted
stromatal aggregation: not forming a crust
stromatal shapes: other than wiry
coremial pegs or remnants: absent
substrates: associated with dung or associated with insect nests or
associated with substrates other than dung or insect nests
ascomatal number per stroma: mostly multiperitheciate
ascomatal ostioles: present
ascomatal configurations: not valsoid
ascomatal orientation: mostly oriented horizontally
ascal apical rings: present
ascus height vs width: usually higher than wide
ascospore cell number: one-celled
ascospore shapes: other than cuboid
ascospore color: colored
ascospore ornamentation: smooth
ascospore germination site morphology: slit-like
perispore dehiscence: indehiscent
cultural gross morphology on oatmeal agar: not highly furrowed
places where teleomorph and anamorph are produced: on the
same stromata in most species
BENEFICIAL USES OF XYLARIA
Some Xylaria sp. species exist as endophytes, and have mutualistic associations with
plants. The fungus secrete toxins to protect the plant from herbivory from other insects or
animals, while the fungus in return feeds on the host’s tissues for nutrition, and its mycelia are
scattered through seed dispersal (Davis, et al., 2003). There is a hypothesis that Xylariaceae
endophytes are quiescent colonizers that will decompose lignin and cellulose later when the
plant dies (adapted from Petrini et al., 1995; Whalley, 1996 as cited by Davis, et al., 2003).
Nonetheless there are also some xylariaceous fungi that only exist as endophytes (adapted
from Rogers, 2000; J. D. Rogers, Washington State University, personal communication as cited
by Davis, et al., 2003). No obvious benefit to living host plants has been documented for
Xylariaceae (Davis, et al., 2003).
A review (Carroll, 1988 as cited by Davis, et al., 2003) of empirical studies on
antagonistic interactions between endophytes and grazers, insects and microbial pathogens
summarizes five general properties of endophyte mutualism: (1) the endophyte is ubiquitous in
a given host, geographically widespread, and causes minimal disease symptoms in the host
plant; (2) vertical transmission or efficient horizontal transmission of the fungus occurs; (3) the
fungus grows throughout host tissue, or, if confined to a particular organ, a high proportion of
such organs are infected; (4) the fungus produces secondary metabolites likely to be antibiotic
or toxic; and (5) the endophyte is taxonomically related to known herbivore or pathogen
A patented extract from Xylaria nigripes, the WulinshenPrime™ in SleepWell™ can
provide important nutrients usually at a low level, to the brain and thus help in its biochemical
processes to promote a more restful and deeper sleep to wake up fully revitalized. This extract
contains essential amino acids, vitamins, minerals, trace elements, glycoproteins, glutamic acid,
γ-aminobutyric acid (GABA) and glutamate decarboxylase. It is well established that glutamic
acid assists the uptake of GABA to specific brain cell receptors. GABA's main function is to
inhibit excitatory neuro-activities to exert a tranquilizing effect on the central nerve system.
Glutamate decarboxylase (GAD) is involved in the synthesis of GABA.
COLONIZATION OF PLASTIC BY XYLARIA SP.
A previous study by Clutario and Cuevas (2001) proved that Xylaria sp. can utilize
polyethylene plastic strips as an alternative carbon source, thereby degrading them into usable
forms for self-sustenance. Through the use of scanning electron microscopy, the proponents of
the said study observed visible damages of the surface structure of the plastic strips. There
were tearing and striations caused by active burrowing of Xylaria hyphae on the polyethylene
material. Plastic is an extremely versatile synthetic material made of high molecular weight,
semi-crystalline polymer prepared from ethylene through the cracking of crude oil, light
petroleum and natural gas (Knapczyk and Simon, 1992 as cited by Clutario and Cuevas, 2001).
For plastic bags alone, it is estimated that some 430,000
gallons of oil are needed to produce 100 million pieces of these omnipresent consumer items on the
planet (EcoWaste Coalition, 2008).