International Journal of Research and Reviews in Pharmacy and Applied science.

Transcription

1 RESEARCH ARTICLE Mohammad Ali, IJRRPAS, 212,DEC, 2(6) , ISSN International Journal of Research and Reviews in Pharmacy and Applied science Mohammad Ali Tajick Ghanbary Department of Mycology & Plant Pathology College of Agronomic Sciences Sari Agriculture and Natural Resources University, P.O.Box 578 Sari,IRAN LABORATORY BIODEGRADATION OF COMMERCIAL EXTRUDED BAGASSE/PP COMPOSITE BY SOME ENVIRONMENT MICROFUNGI ABSTRACT The ability of some saprophytic fungi to degradation of wood-plastic composite (WPC) were investigated by measuring released sugar content in medium. Crashed pieces of wood-plastic composites were incubated with fifteen different genus filamentous fungi for 3 days in 3 C. Sugar assays started from third day after inoculation and repeated each two days up to 32 nd day. Reaction of glucose and related reagent were subjected to colorimetric measurment at 525 nm. All species showed ability of WPC degradation and Statistical analysis showed significant variation in releasing sugar among different tested genera and species. Glucose levels in some species have decreased in initial days post inoculation, then increased in next days. Penicillium and Trichoderma had highest and Cladobotryum and Pestalotiopsis least ability for in vitro WPC degradation. Its obvious that soil fungi have high ability for WPC degradation. KEYWORDS: Bagasse Composites, Micromycetes, Sugar assay 113

2 RESEARCH ARTICLE Mohammad Ali, IJRRPAS, 212,DEC, 2(6) , ISSN INTRODUCTION Plastics and industrial polymers joined to human living environment during last century. Limitations on natural resources specially wood persuaded us to find some substitutions for it to make our needs. The human found many many alternatives but some unwanted problems for his environment were produced too. All alternatives have limited lifetime and after their usage will return to the environment as wastes. Use of industrial polymers like wood plastic polymers is in progress today as many prefabricated products like frames of doors and windows and others. An interest on its application is its resistance to biological attacks during use and the other its degradability after completion its lifetime and being a waste. Commercial WPC, made from wood derived lignocellulose- particles and melt-blended in a screw extruder with a plastic matrix, are mainly a plastic material (in terms of properties and appearance) which contain some lignocellulose. Biological degradation of WPC may include attack by decaying fungi, molds, algae, termites, and marine borers There are three levels of microbial effects on wood plastic composites. First, when mold forms colored spots on the surface of deck boards, but it does not degrade the material, which remains structurally sound. In this case mold feeds itself by dust, airborne particles such as pollen, and so on. Second, when mold and other fungi insignificantly consume some ingredients of the composite formulation as nutrients. Third, when fungi specifically and rapidly attack wood/cellulose fiber in the composites, which in turn causes diminishing of mechanical properties of the WPC. Laboratory and field studies have found fungal degradation of WPC despite of the plastic surrounding of the wood particles. Many fungi are classified as mildew, or mold, or wood-staining fungi rather than wood-degrading fungi because they primarily just discolor wood. Mildew fungi generally do not cause a reduction of cellulose or composite materials in strength. However, as both mildew and decay fungi grow in same conditions, the presence of molds can be taken as a signal of a potential decay. Morris and Cooper isolated and identified brown and white rot fungi as well as one blue stain fungus growing on a WPC boardwalk in Florida which had been in service for four years. This boardwalk consisted of 5% recycled wood fiber and 5% recycled plastic bags and film. There is only limit publication about WPC degradation by fungi and other microorganism. In this research few saprophytic fungal genera for only one highlighted biochemical process were tested in laboratory conditions. This study was aimed to screen of several saprophytic fungal for the ability WPC degradation. Material and Methods Fungal isolates and maintenance Fifteen different fungal genera belonging to Aspergillus, Alternaria, Cladobotryum, Cladosporium, Cunninghamella, Fusarium Metarhizium, Mucor, Penicillium, Pestalotiopsis, Rhizoctonia, Stemphylium, Trichoderma, Trichotecium, Thamnidium and Volutella which were isolated from cultural soils were selected for current experiments. The isolates were grown on PDA slants and stored at 4 º C. 114

3 RESEARCH ARTICLE Mohammad Ali, IJRRPAS, 212,DEC, 2(6) , ISSN Preparation of WPC medium WPC medium was containing 2gr sawdust WPC per 5 ml distilled water that distributed for each 25 ml erlenmeyers then autoclaved at 12C for 2 min. Inoculation and sampling Each flask inoculated with then flasks treated at 25 º C for 27 days. Sampling was started three days after inoculation and repeated each two days for sugar assays. Sugar assay Five hundred µl of broth medium in each clean test tube were subjected for released sugar assays. Released sugars concentrations were determined using Arsenate-Molybdate reagent (Kossem and Nannipieri, 1995). Results and Discussion Wood-plastic composites (WPC) are a group of relatively new materials made from a combination of wood particles and plastics, most frequently thermoplastic resins. WPCs with recycled wood fiber/flour have gained popularity due to the low cost of recycled wood to the manufacturers. Recent study has shown that WPCs are not immune from the biological degradation. Fungi are well known agents of decomposition of organic matter in general as reported by Lynd. Screening of different genera, species and even isolates is the first step for finding acceptable enzyme producer isolates. Members of the Trichoderma, Aspergillus and Penicillium genera have been extensively studied, particularly due to their high ability to degradation of organic matters. In current research WPC degradation by a sharp saprophytic soil inhabitant fungus are examined. Fungi which cause discoloration of wood in storage and service are generally described as staining fungi while those that grow superficially on wood are called molds. Staining and mold fungi are members of the Ascomycetes and Deuteromycetes (Fungi Imperfecti) although a few of the molds are Zygomycetes and are classified in the Mucorales. In the short term, mold and staining fungi may represent a more relevant issue with WPC than decay fungi since these first two types of fungi develop more quickly on such material. Many of mold fungi known to grow on wood have also been isolated from plastics, for example, Aureobasidium, Aspergillus and Penicillium, therefore have importance as screening organisms for both plastic and wood. According to anecdotal evidence, WPC are susceptible to mold and staining fungi, however, very little detailed information on this issue is available in the scientific literature. 115

4 RESEARCH ARTICLE Mohammad Ali, IJRRPAS, 212,DEC, 2(6) , ISSN Laks et al. (25), reported that WPCs containing more than 5% weight ratio were degraded by brown rot (Gloeophyllum striatum) and white rot (Pycnoporus sanguineous) fungi. Additionally, Morris and Cooper observed fungal decay on wood composite plastic after 4 years of exposure in southern Florida. Mold and biological stain have been reported as one of the aesthetic issue of WPCs. Wood decay fungi, such as Trichoderma sp., after attach to the surface, secrete a family of cellulolytic enzymes. The enzymes, acting in concert, hydrolyze cellulose fiber eventually to glucose, the Principal building sugar of cellulose chains, and the glucose is consumed by the fungus. All species in study showed noticeable ability on WPC degradation and Statistical analysis showed significant variation in releasing sugar among tested different genus and species. According to results among treated species, Trichoderma and Penicillium had highest released sugars and species Cladobotryum and Pestalotiopsis and among all species in this study showed the lowest WPC degradation activity. Variations in glucose levels in most of tested genera in this study showed that fungus grow on sugar residue in medium remained on cellulosic parts of WPC. After decrease in sugar content in medium, the fungus was induced to secrete cellulolytic enzymes which cause further increase glucose levels in medium. But some genera such as Penicillium, Trichoderma and Mucor which are strong saprophytes, initial degradation activity were observed with inoculation. Thereupon glucose levels increase in medium uppermost. Finally, different saprophytic fungal species have dissimilar behaviors and had variable speeds in WPC degradation. In current work a group of strong soil saprophytic flora were tested for monitoring how they act in their natural habit. Soil biologists have fully aware of the importance of biochemical process take place in soil that thousands of microorganisms play major or minor roles. In present study only one highlighted biochemical process from a few saprophytic fungal species are tested in laboratory conditions. 116

5 RESEARCH ARTICLE Mohammad Ali, IJRRPAS, 212,DEC, 2(6) , ISSN Aspergillus Alternaria Cladobotryum Cladosporium Cunninghamella Fusarium Mettarrhyzium Species Penicillium Mucor Pestalotiopsis Stemphylium Rhizoctonia Trichoderma Trichotecium Thamnidium Volutella Fig. 1. Variations in released sugars from different species 117

6 RESEARCH ARTICLE Mohammad Ali, IJRRPAS, 212,DEC, 2(6) , ISSN Trichotecium.6 Metarhizium Released sugars (g/lit) A Days ( after inoculation) B Trichoderma.6 trichoderma.6 volutella.5.5 Volutella C D 118

7 RESEARCH ARTICLE Mohammad Ali, IJRRPAS, 212,DEC, 2(6) , ISSN stemphilium.6 stemphilium.6 Rhizoctonia R eleased sug ars (g/lit) E F.3 Alternaria.14 Penicillium Days (after inocuation) G H 119

8 RESEARCH ARTICLE Mohammad Ali, IJRRPAS, 212,DEC, 2(6) , ISSN Fusarium fusarium.6 Cladobotryum I J 111

9 RESEARCH ARTICLE Mohammad Ali, IJRRPAS, 212,DEC, 2(6) , ISSN Mucor mucor.6 Cunninghamella.5.5 Released sugars (g /lit) K L Pestalotiopsis.6 Cladosporium cladosporium

10 RESEARCH ARTICLE Mohammad Ali, IJRRPAS, 212,DEC, 2(6) , ISSN Thamnidium O Fig. 2. Variations in released sugars from different species during sampling days in WPC medium. REFERENCES 1.Kamdem D P, Jiang H, Cui W, Freed J, Matuana L M. Properties of wood plastic composites made of recycled HDPE and wood flour from CCA-treated wood removed from service. Composites Part A: Applied Science and Manufacturing.24 ; 35: Karimi A N, Tajvidi M. Effect of compatibilizer on the natural durability of wood flour/high density polyethylene composites against rainbow fungus (Coriolus versicolor). Polymer composites : Lopez J L, Cooper P A and Sain M, Evaluation of proposed test methods to determine decay resistance of natural fiber plastic composites. Forest Products Journal and Index : Lynd L R, Weimer P J, Van Zyl W H, Pretorius I S, Microbial cellulose utilization: biotechnology. Microbiology and molecular biology reviews :

11 RESEARCH ARTICLE Mohammad Ali, IJRRPAS, 212,DEC, 2(6) , ISSN Schauwecker C, Morrell J J, McDonald A G, Fabiyi J S. Degradation of a wood-plastic composite exposed under tropical conditions. Forest products journal : Schirp A, Ibach R E, Pendleton D E, Wolcott M P. Biological degradation of wood-plastic composites (WPC) and strategies for improving the resistance of WPC against biological decay. 28: ACS Publications. 7. Schirp A, Wolcott M P, Influence of fungal decay and moisture absorption on mechanical properties of extruded wood-plastic composites. Wood and fiber science :