The Potential of Trichoderma harzianum as a Biodegradable Solution in Decomposing Low

Density and High Density Polyethylene Waste Plastics

A research proposal presented to the Faculty of College of Arts and Sciences

Cagayan State University

Carig Campus, Tuguegarao City

In partial fulfillment of the requirements of the

Degree of Bachelor of Science in Biology

Lina Riza N. Montero

Prof. Osmond Narag

Research Instructor

Chapter I

Introduction

Plastics are ubiquitous in the modern world. Polyethylene is the world's most

common plastic. It finds innumerable applications in everything from bottles and jugs to

shopping bags and children's toys. It owes its surprising versatility to its properties and molecular

structure. There are different kinds of polyethylene available; two of the most common are high-

density polyethylene or HDPE and low-density polyethylene or LDPE.

LDPE was the first PE to be developed. It has low-density levels and only a small amount

of branching. It is very flexible and easy to clean. It is often used to make plastic film wrap and

plastic bags. Additionally, it is used to make plastic items that need to be molded, such as plastic

bottles used in labs. While HDPE has higher density levels; it is characterized by a linear

structure consisting of no branching. That makes HDPE stronger and more resistant to

chemicals. It is most commonly used for items requiring blow molding techniques, such as toys,

automobile parts and bottles. It is also used to create cutting boards since it meets FDA food

service standards.

Although most of these plastics can be recycled, much of it ends up in our trash cans.

There are concerns in the environmental industry that, since these plastics do not break down

easily in a landfill, there will be many future negative effects due to our overuse of these

products. According to the American Chemistry Council's Resin Production and Sales Stats

report, released in November 2009, HDPE is the most common plastic and LDPE is the fifth

most common plastic produced in the U.S. The slow rate at which plastic degrades vs. the

amount produced makes the disposal of it an environmental issue. To overcome this ever-

increasing serious problem, decomposition of waste plastics seems to be a fruitful solution.

Certain bacterial strains had been discovered to degrade these plastics, however, seeing

that there are various fungal strains that have the potential to be involved in the process of

decomposition that can contribute to the adamant pollution and equilibrium in nature. This study

will provide information regarding the potency of Trichoderma particularly the T. harzianum as

a natural and valuable decomposing agent in non- biodegradable matter in order to reduce the

utilization of chemicals capable of decomposition.

Trichoderma is a genus of fungi that is present in all soils, decaying wood and vegetable

matter. Their dominance in soil may be attributed to their diverse metabolic capability and

aggressive competitive nature (Lewis and Papavizas, 1991). These characteristics make them

significant decomposers of woody and herbaceous material and are also necrotrophic against

other decomposers. Many species in this genus can be characterized as opportunistic a virulent

plant symbionts, the ability of several Trichoderma species to form mutualistic endophytic

relationships with several plant species. One of which species is the Trichoderma harzianum, the

most frequent Trichoderma species cultivated from soil worldwide. That displays a remarkable

diversity of lifestyles ranging from saprotrophy in free soil and dead wood, in rhizosphere and on

dead fungal biomass to biotrophy in necrotrophic mycoparasisitic attacks of other fungi and

endophytic associations with plants (http://genome.jgi.doe.gov). In addition to, it is reported that

T. harzianum may have the capability of degrading organochlorine pesticides such as DDT,

dieldrin, endosulfan, pentachloronitrobenzene, pentachlorophenol and hence has potential

applications for bioremediation (Kelley, 1976). These pesticides contain petroleum oils that are

refined from crude oil which is the main ingredient of plastic.

Objectives of the Study

Generally, this study aims to understand the microphysical potency of T. harzianum as an

effective biodegradable solution in decomposing waste plastics. It specifically aims to:

To describe the potential of T. harzianum as potential decomposer,

To observe the physical manifestations of exposing LPDE and HPDE plastics to

T. harzianum under experimental condition,

To determine the efficiency of T. harzianum as a decomposer,

To determine the rate of decomposition made by T. harzianum to LPDE and

HPDE plastics.

Scope and Delimitation of the Study

This study is intended only for the determination and provision of Trichoderma

specifically the Trichoderma harzianum as potential and effective decomposer of non-

biodegradable plastics (HDPE and LDPE).

Time and Place of the Study

Cagayan State University, Carig Campus, Tuguegarao City, DOST Lab from September

to November 2014.

Definition of terms

Composting is the decomposition of plant remains and other materials to reduce the

volume of garbage needlessly sent to landfills for disposal.

Decomposer organisms that break down unused dead material that carry out the natural

process of decomposition.

Fungi any member of a large group of eukaryotic organisms that includes

microorganisms such as yeasts and molds, as well as the more familiar mushrooms.

High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a

polyethylene thermoplastic made from petroleum.

Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene

Mycoparasitic is a parasitic fungus whose host is another fungus.

Necrotrophic a parasite that kills its host, then feeds on the dead matter.

Polyethylene is the most common plastic the polymer that makes grocery bags

Potato Dextrose Agar is a nonselective medium for the cultivation of yeasts and molds.

Trichoderma a genus of fungi that is present in all soils, where they are the most

prevalent culturable fungi. Many species in this genus can be characterized as opportunistic

avirulent plant symbionts.

T. harzianum are the most frequent Trichoderma species cultivated from soil worldwide

that may have the potential to degrade plastics.

Chapter II

Review of Related Literature

The Nature and Effect of Plastics

Plastics have become a necessary commodity in today’s world. Everyone knowingly or

unknowingly uses plastic substances. Karki (2008) discusses that plastic is used not only for

making plastic bags but also for producing products that cover parts of vehicles that need to be

protected. The word plastic comes from the Greek word plastikos, which means, ‘able to be

molded into different shapes (Joel FR., 1995). The plastics we use are made from, inorganic and

organic raw material such as carbon, silicon, nitrogen, oxygen, chloride and hydrogen. Basic

material used for making plastic are extracted from coal, oil and natural gas. Plastics are defined

as the polymers which become mobile on heating and thus can be cast into moulds. Plastics are

nonmetallic mouldable compounds and the materials made from them, can be pushed into almost

any desirable shape and then retain that shape (Seymour RB., 1989) Commodity plastics are used

in packaging, disposable diaper backing, fishing nets and agricultural film. They include

polymers such as polyethylene, polypropylene, polystyrene, polyvinylchloride, polyurethane,

polyethyleneterepthalate, nylon (Shah, 2007). Improperly disposed plastic materials are a

significant source of environmental pollution, potentially harming life. The plastic sheets or bags

do not allow water and air to go into earth which causes infertility of soil, preventing degradation

of other normal substances, depletion of underground water source and danger to animal life. In

seas also plastic rubbish from ropes and nets to the plastic bands from beer packs chokes and

entangles marine mammals (Cooper and Vaughan, 1967). According to the municipal

administrators carry bags are the main cause of blocked drains and thus municipal wastes cannot

be incinerated leading to accumulated garage, sludge, junk (Roff and Scott, 1971). On this living

planet, a biosphere, plastic is a raging parasite that devours and pollutes everything

(http://www.mnn.com/greentech/research-innovations/blogs/boydiscovers-microbe-that-eats-

plastic).

Fungi as a Decomposer

Fungi are any member of a large group of eukaryotic organisms that includes

microorganisms such as yeasts and molds, as well as the more familiar mushrooms. Abundant

worldwide, most fungi are inconspicuous because of the small size of their structures, and their

cryptic lifestyles in soil, on dead matter, and as symbionts of plants, animals, or other fungi.

Fungi perform an essential role in the decomposition of organic matter and have fundamental

roles in nutrient cycling and exchange (http://en.wikipedia.org). Most fungi are decomposers.

Fungi break down, or decompose, the complex carbon compounds that are part of living matter.

They absorb nutrients and leave behind simpler compounds. Fungi are heterotrophs. They get

their energy from living or once living matter. They, along with bacteria, decompose the bodies

of dead plants and animals. They also decompose materials left behind by organisms, such as

fallen leaves, shed skin, and animal droppings. One interesting application of a mold is the use of

the fungus Trichoderma. This mold grows in soil. The digestive chemicals it produces are used

to give blue jeans a stonewashed look

(www.d123.org/olhms/ebarlos/documents/Fungi2.4C3.pdf ). In addition to, several reports

appeared that fungi don’t just decompose organic matter but also degrade inorganic ones like

Polyurethanes (PU) that are present in many aspects of modern life. They represent a class of

polymers that have found a widespread use in the medical, automotive and industrial fields.

Studies revealed that polyester-type PUs is more susceptible to fungal attack than other forms

(Kaplan et al., 1968).

Studies Related to the Decomposition of Waste plastics using Fungi

When UV rays strike plastic, they break the bonds holding the long molecular chain

together. Over time, this can turn a big piece of plastic into lots of little pieces. However, plastic

buried in a landfill rarely sees the light of the day, but in the ocean which is where a lot of plastic

wastes end up. Plastics are bathed in as much light as water. In 2009, researchers from Nihon

University in Chiba Japan, found that in warm ocean water can degrade in as little as a year. This

doesn’t sound so bad until you realize those small bits of plastic are toxic chemicals such as

bisphenol A (BPA) and PS oligomer (Harris and William, 2009). In the early 1980s the research

on degradability of plastics began. Past research has isolated and identified the use of

Trichoderma spp. for bioconversion of solid wastes (kitchen waste, humus, compost and soil). In

the study, a total of 135 isolates of Trichoderma were isolated. These 135 isolates were divided

into 5 aggregate groups. Representative isolates from each group were sent for identification. It

is then concluded that the most frequently isolated species was T. harzianum and was identified

as an effective agent for solid waste conversion using spore suspension. A same study targeted

the potential of fungal isolates as a potential bioconversion agent of municipal solid waste.

Samples of fungal strains were collected from different waste disposal site. Overall among the 5

fungal strains used in the study Tricoderma spp. were the most effective strain for the solid waste

decomposition. Bari (2007), reported that T. harzianum was the most effective strain for solid

waste decomposition and showed the highest weight loss (31.8%) when the culture disc approach

was used but present results are partially in accordance with findings of Zheng and Shetty and

Martin and Dale. These plastics differ in degradation rate, application, and price. In one

development, plastics' inertness and resistance to microbial attack was reduced by incorporating

starch and later prooxidants (transition metals and oil) (Griffin, 1973). Three types of

degradation of polyethylene in these degradable starch-polyethylene polymers can occur by

different molecular mechanisms: chemical degradation, photodegradation and biological

degradation. Chemical degradation occurs when the prooxidants catalyze the formation of free

radicals in polyethylene, which react with molecular oxygen to attack the polyethylene matrix

(Johnson et al.). Heat and oxygen accelerate this chain scission of the polyethylene.

Photodegradation also occurs within the polyethylene matrix whereby UV light catalyzes the

autoxidation and generation of free radicals (David et al., 1992). Biological degradation of these

polyethylene films has been reported in pureculture studies with various microorganisms such as

Streptomyces sp. (Lee et al., 1991), Phanerochaete sp.(Ali et al., 2009), Penicillium, Fusarium,,

Alternaria, Spicaria spp., Aspergillus (Ibrahim et al., 2011), Aureobasidium, Poecilomyces

(Mehdi et al., 2010) after chemical degradation was initiated and with their corresponding

extracellular enzymes.

The Mechanism of Trichoderma spp.

Trichoderma spp. are free- living that are highly interactive in root, soil and foliar

environments. It has been known for many years that they produce a wide range of antibiotic

substances and that they parasitize other fungi. The first description of a fungus named

Trichoderma dates back to 17941 (Persoon, 1794), and in 1865 a link to the state of a Hypocrea

species was suggested (Tulasne, 1865). But the different species assigned to the genus

Trichoderma hypocrea were difficult to distinguish morphologically. It was even proposed to

reduce taxonomy to only a single species, Trichoderma viride. Hence, it took until 1969 that

development of a concept for identification was initiated (Rifai, 1969; Samuels, 2006).

Thereafter, numerous new species of Trichodermal hypocrea were discovered, and by 2006 the

genus already comprised more than 100 phylogenetically defined species (Druzhininae et al.,

2006). Trichoderma spp. are ubiquitous colonizers of cellulosic materials and are often found

wherever decaying plant material is available (Kubicek et al. 2008), as well as in the rhizosphere

of plants where they can induce systemic resistance against pathogens (Harman, 2000). The

search for potent biomass regarding enzymes and organisms also led to isolation of these fungi

from unexpected sources such as cockroaches (Yoder et al. 2008), marine mussels and shellfish

(Sallenave et al. 1999). Trichoderma spp. are characterized by rapid growth, mostly bright green

conidia and a repetitively branched condiophore structure (Gams and Bissett, 1998). The sexual

stage when found is within the Ascomycetes in the genus Hypocrea. Trichoderma spp. possesses

innate resistance to most agricultural chemicals, including fungicides, although individual strains

differ in their resistance. Some lines have been selected or modified to be resistant to specific

chemicals. Composting is the most suitable option among the wastes management strategies with

economic and environmental profits since this process reduces the bulk volume of organic

materials, eliminates the risk of spreading of pathogens, weed seeds or parasites associated with

direct land application of manure and leads to final stabilized products which can improve and

sustain soil fertility. However, composting of lignocellulosic EFB takes a longer period of time

which is considered as the most blocking stump of this eco-friendly disposal technique (Chen et

al., 1992). Trichoderma spp. are widely known as a lignocellulose decomposer because they are

filamentous and have the ability to produce profilic spores which can invade substrates quickly

(Tengerdy and Szakacs, 2003). Various studies have shown that composting of lignocellulosic

materials preinoculated with potential Trichoderma spp. can reduce the time of biodegradation

(Mohammed et al., 2012). However, for an economically competitive process an increase in

efficiency of more than 40 fold would be necessary, which is a formidable challenge for research

with Trichoderma. Besides these major applications of Trichoderma spp. the fields of green and

white biotechnology become increasingly important for environmentally safe production of

enzymes and antibiotics. The extensive studies on diverse physiological traits available and still

progressing for Trichoderma make these fungi versatile model organisms for research on both

industrial fermentations as well as natural phenomena.

Trichoderma harzainum

The filamentous fungus Trichoderma harzianum is the genetically distinct temperate

agamospecies belonging to the group of closely related (cryptic), albeit diverse, species of the

Harzianum clade of Trichoderma (teleomorph Hypocrea, Ascomycota, Dikarya). In the broad

taxonomic sense these fungi (T. harzianum) are the most frequent Trichoderma species

cultivated from soil worldwide. They display a remarkable diversity of lifestyles ranging from

saprotrophy in free soil and dead wood, in rhizosphere and on dead fungal biomass to biotrophy

in necrotrophic mycoparasisitic attacks of other fungi and endophytic associations with plants.

Because of its mycotrophyc ability T. harzianum has often been set equal to Trichoderma-based

biocontrol agents in general, as it is the principal component in several commercial biofungicide

formulations. It is used for foliar application, seed and soil treatments for suppression of various

diseases causing by such pathogens as Botrytis, Fusarium and Penicillium sp. Although T.

harzianum is not a causative agent of the green mold disease on mushroom farms it is frequently

isolated from infected cultures of Agaricus and Pleurotus and respective substrata. Interestingly,

the causative agents of the mushroom green mold diseases (T. aggressivum, T. pleurotum and T.

pleuroticola, respectively) also belong to the Harzianum clade, i.e. are closely related to T.

harzianum. Similar to T. virens (teleomorph Hypocrea virens), a rhizosphere-competent T.

harzianum may not only grow on plant roots, but its hyphae penetrate root epidermis

(endophytism), which enhances plant growth and immune system. Some molecular mechanisms

of Trichoderma mycotrophy and interactions with plants - such as the role and regulation of

formation of cell wall hydrolytic enzymes and antagonistic secondary metabolites - have been

intensively investigated in T. harzianum. It is reported that T. harzianum is capable of degrading

organochlorine pesticides such as DDT, dieldrin, endosulfan, pentachloronitrobenzene,

pentachlorophenol and hence has potential applications for bioremediation (Kelley, 1976). As a

mycoparasitic and antagonistic fungus T. harzianum is suggested to be a powerful environmental

opportunist, which is able to interplay in communities of invasive Trichoderma spp. in various

disturbed ecosystems and thus replace or suppress the local mycofauna. Hence the genome

sequence of such an outstanding opportunistic fungus as T. harzianum is expected to provide a

platform to identify genetic resource to be used in pest control, development of biofungicides,

improvement of plant health, decomposition of plastics and environmental monitoring

(http://genome.jgi.doe.gov/).

Chapter III

Materials and Methods

Materials

The equipment, supplies and materials that will be used in this study are the following:

cultured stock of T. harzianum (culture pellets & spore suspension), petri dish, LDPE and HDPE

plastics, Erlenmayer flask (150 mL), 2% Tween 20, centrifuge, test tubes, scissors, incubator,

autoclave, PDA (potato dextrose agar), Potato Dextrose Broth, distilled water and record

notebook.

Methods

Treatments

The following treatments that will be used to conduct the study are:

T1 – Control1 LDPE (no inoculation)

T2 – Control 2 HDPE (no inoculation)

T3 – 50g of Low Density Polyethylene (LDPE) cut into 2-3mm with spore suspension of T.

harzianum

T4 – 50g of Low Density Polyethylene (LDPE) cut into 2-3mm with culture pellet of T.

harzianum

T5 – 50g of High Density Polyethylene (HDPE) cut into 2-3mm with spore suspension of T.

harzianum

T6 – 50g of High Density Polyethylene (HDPE) cut into 2-3mm with culture pellet of T.

harzianum

Procedures

A. Obtaining of Subculture and Treatments

T. harzianum, will be obtained from the culture stock of the University of the Philippines

–Los Banos, Campus Laboratory. The fungus will be maintained in Petri dishes of PDA (potato

dextrose agar). After inoculating from the original slant culture stock, the petri dishes will be

incubated at 280C for 4-7 days and subsequently stored at 5

0C. Spore suspension will be obtained

by washing the Petri dish cultures with a sterile aqueous solution of 2% Tween 20. The resulting

suspension will be centrifuged (∼2800×g, 5 min). Fungal pellets will be obtained from the

germination of spores that are suspended in shake flasks in the preliminary cultivation stage.

B. Preparation of waste plastics for decomposition

LDPE and HDPE plastics will be collected from the garbage center of the CSU, Carig

Campus. Aseptic condition will be maintained as far as possible during the collection. The

samples will be cut into 2-3 mm pieces and 50 g of each will be aliquotted into a 150 mL

Erlenmayer flask, which will then be sealed with a cotton plug. The Erlenmayer flask containing

waste plastic will then be autoclaved at 121 °C for 15 min.

C. Liquid shaking culture test method

A 50g plastic bag cut into 2-3mm will be added to Erlenmeyer flask (150 mL)containing

10 mL Potato Dextrose Broth, sterilized by autoclave at 121 °C for 20 min. The test isolate (3

culture pellets/50g) will be added to the test medium, properly stoppered, and incubated at 30 °C

with reciprocal shaking (120 oscillations/min). The degradation of the LDPE and HDPE plastics

will be monitored by measuring the weight of the plastics before and after incubation. At the end

of the incubation period, the pieces of plastics will be taken out and washed several times with

distilled water. Next, they will be dried overnight at 80°C and the changes will be observed.

D. Petri dish test method

Potato Dextrose Agar will be prepared by adding 15 g of agar to 1 L of basal medium, followed

by autoclaving for 20 min and pouring it into petri dishes. Sterilized pieces of plastic bag will be

overlaid on the medium surface, and the test isolate (1.0 mL of spore suspension) will be added

over the plastic bag pieces. At the end of incubation period, the pieces of plastic bag will be

taken out and will be washed several times with distilled water. They will be next dried over

night at 80 °C and the changes will be observed.

E. Data Collection Procedures

The data will be collected based on the observations that will be made during the

experiment like changes in color, odor, volume loss and weight loss of waste plastic bag. It will

be observed at 10-day intervals up to 60 days.

For measurement of volume loss (%), the following formula will be used:

Volume loss (%) = V-V1/V × 100 where V is initial volume, V1 is final volume.

Weight loss (%) of plastic bag will be calculated employing the formula:

Weight loss (%) = W-W1/W × 100 where W is initial weight, W1 is final weight.

F. Statistical Tools and Analysis

The experiment will be conducted using a complete randomized design (CRD) with 3

treatments replicated 3 times. Correlations will be calculated between the sample’s physio-

chemical characteristics and cfus. Results of all analyses will be judged for significance at the

5% level. The data will be statistically analyzed with the help of the computer package MSTAT-

C.

Literature Cited

Andleeb, Naima Atique, Pir Bux Ghumro, Safia Ahmed and Abdul Hameed. Studies on

Biodegradation of Cellulose Blended Polyvinyl Chloride Films, International Journal Of

Agriculture and Biology. Aug. 2009: 09–175.

Amer Ali Shah. Role of microorganisms in the biodegradation of plastics. Department of

Microbiology Islamabad, 1 May 2007.

Bari M.A., Begum, M.F., Sarker, K.K., Rahma, M.A., Kabir, A.H., Alam, M.F. Mode of action

of Trichoderma spp. on organic solid waste for bioconversion. Plant Environ. Develop., 2007,1:

61-66.

Chen, Y., Inbar, Y., Hadar, Y. Composted residues reduce peat and pesticide use. Biocycle. June

1992, 48–51.

Cooper W. and Vaughan G. Recent Developments in Polymerization of Conjugated dienes.

Progress in Polymer Science. 14 May 1967: 91-160.

David, C., Trojan M. and Daro A. Photodegradation of polyethylene: comparison of various

photoinitiators in natural weathering conditions. Polymer Degradation Stability. Sept. 1992;

37:233- 245.

Druzhinina, I.S., Kopchinskiy, A.G., Komon, M., Bissett, J., Szakacs, G., Kubicek, C.P. An

oligonucleotide barcode for species identification in Trichoderma and Hypocrea. Fungal Genet

Biol PubMed. Mar. 2005;24:813-828. <www.ncbi.nlm.nih.gov/pubmed/16154784>.

Gams W., Bissett J. Morphology and identification of Trichoderma. In: Harmann GE, Kubicek

CP, editors. Trichoderma and Gliocladium. London: Taylor and Francis; 1998, pp. 3-34.

Griffin, G.J.L. Biodegradable fillers in thermoplastics. American Chemical Society Division of

Polymer Chemistry. 1 June 1973;33:88-92.

Ibrahim N Ibrahim, Anwar Maraqa, Khalid M Hameed, Ismail M Saadoun and Hamzah M

Joel F.R. Polymer science and technology: Introduction to polymer science. May, 1995: 4-9.

Maswadeh. Assessment of potential plastic degrading fungi in Jordanian habitats. 13 Oct. 2011.

<journals.tubitak.gov.tr/biology/issues/biy-11.../biy-35-5-3-0901-9.pdf >.

Kaplan, A. M., R. T. Darby, M. Greenberger, and M. R. Rogers. Microbiological deterioration of

polyutherene systems. Journal of Industrial Microbiology and Biotechnology Oct. 1998; 9:201-

217.

Kelley, W.D. Evaluation of Trichoderma harzianum impregnated clay granules as a biocontrol

for damping off of pine seedlings caused by Phytophyhora cinnamomi. Phytopathology Jan.

1976; 66: 1023-27.

Lee, B., Pometto A.L., Fratzke A. and Bailey T.B. Application on microbiology 1991.

Masayuki, Shimao.” Biodegradation of plastics.” Current Opinion in Biotechnology.

2001;12:242–247.

Martin S.B., Dale J.L. Biodegradation of turf thatch with wood decay fungi. Phytopathology,

Jan. 1980; 70: 297-371.

Mehdi, Borghei, Abdolreza Karbassi, Shahrzad Khoramnejadian, Abdolrasoul Oromiehie and

Amir hossein Javid. Microbial biodegradable potato starch based low density polyethylene.

African Journal of Biotechnology. 9 Mar. 2010; 9:4075-4080.

Mohammad, N., Alam M.Z., Kabbashi N.A., Ahsan A. Effective composting of oil palm

industrial waste by filamentous fungi: A review. Resources Conservation and Recycling

Aug. 2012; 58: 69– 78.

Person, C.H. Disposita methodica fungorum. Neues Magazin für die Botanik. Jan. 1794; 1:81-

128.

Rifai, M.A. A revision of the genus Trichoderma. Mycological papers no. 116. Commonwealth

Mycological Institute, Kew, Surrey, England. 1969.

Roff, W.J. and Scott J.R. Fibres, film, plastics and rubbers, butterworths. London , May

1971:66-71.

Salma S. and Gunarto. Trichoderma activity on cellulose degradation. Penelitian Pertanian

Tanaman Pangan. 1996, 15:43

Sallenave C, Pouchus YF, Bardouil M, Lassus P, Roquebert MF, Verbist JF. Bioaccumulation of

mytoxins by selfish: contamination of mussels by metabolites of a Trichoderma pseudokoningii

SMF2. FEMS Microbiol Lett. Oct. 2009;299: 135-142.

Samuels, G.J. Trichoderma: A review of biology and systematics of the genus. Mycological

Research. 1996: 923-935.

Scott, G. “Photo-biodegradable plastics.” Their role in the protection of the environment, Polym

Degrad Stability. 1990;29:135- 154.

Seymour R.B. Polymer Science Before and After 1899: Notable developments during the life

time of Mautis Dekker. J Macromol Sci chem. 1989;26:1023-1032.

Tengerdy, R.P., Szakacs G. Biodegradation of lignocellulose in solid substrate fermentation.

Biochem Eng. 2003: 169-179.

Thomas-Hope, H.E. Solid waste management: Critical issues for developing countries.

University of the West Indies Press, Kingston, Jamaica: Canoe, 1998.

Yoder, J.A., Glenn B.D., Benoit J.B., Zettler L.W. The giant Madagascar hissing-cockroach

(Gromphadorhina portentosa) as a source of antagonistic moulds: concerns arising from its use in

a public setting. Mycoses. 2008. 51: 95-98. . (PubMed)

Zheng, Z., Shetty K. Cranberry processing waste for solid fungal inoculants production.

Proc.Biochem., 1998, 33: 323-329.