Studying the biodegradation of plastic in mature composts will help in understanding the eventual fate of such plastic waste. Although foams provide numerous benefits, they also cause a significant environmental litter problem because of their recalcitrant and xenobiotic nature. Synthetic plastics are emerging environmental contaminants that have been found to accumulate within marine waters worldwide. Pdf plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. Biodegradation of plastics using nonconventional methods promises a future free of accumulation of commodity plastics used in packaging and commercial polymers, which are the most abundant form of plastic wastes. Table 2 shows the list of microorganisms and their plastic degrading efficiencies. Biodegradable plastics are plastics that can be decomposed by the action of living organisms, usually microbes, into water, carbon dioxide, and biomass. It never ceases to infuriate me when i see the results of intentional and accidental littering. Biodegradation of this plastic has been poorly explored, and most of. Despite many years of development, these plastics have yet to make major impact in the marketplace because of relatively high production costs 6. In general, biobased and biodegradable plastics are more expensive than fossilbased plastics on a weight basis. In this study, we evaluated the effect of biodegradationpromoting additives on the biodegradation of. New perspectives in plastic biodegradation sciencedirect. Degradation of plastics under anaerobic conditions.
Biodegradable plastics are commonly produced with renewable raw materials, microorganisms, petrochemicals, or combinations of all three. The method that is most reliable and is already in common use in many countries is. Biobased and biodegradable plastics facts and figures. Degradation means decay, and the bio prefix means that the decay is carried out by a huge assortment of bacteria, fungi, insects, worms, and other organisms that eat dead material and recycle it into new. Bioremediation of plastic and rubber by endophytic fungi. Knowledge on the total amount and distribution of plastics. The type of biodegradation environment and the parameters which control it play an important role in controlling the rate of biodegradation figure 3.
However, there is a lot of uncertainty about their effectiveness in degrading polymers in different environments. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. Biodegradation of polyethylene and plastic mixtures in. Final analysis showed that alkanolamine concentrations were reduced to levels below the det ection limit following treatment, from an initial concentration of 15,000 mgkg. If plastics fragment and the resulting particles cannot be. In this study, we investigate the biodegradation of polyethylene pe and mixed plastics pe and ps in a previously untested strain of t. Biodegradable plastics are not readily distinguishable from nondegradable plastics therefore other means of marking them are necessary so that they can be properly used and disposed of. Swanson biopolymer research unit, northern regional research center, agricultural research service, u. By contrast the supply of raw material for oilbased plastics is for all practical purposes unlimited for the foreseeable future.
Polyethylene pe has been considered nonbiodegradable for decades. Large collections of endophytes from ecuador will be screened for degradation of different plastics and rubbers using visual clearance assays, staining of degradation products, gel permeation chromatography and scanning electron microscopy. Complete biodegradation of plastic occurs when none of the original polymer remains, a process involving microbial action. In a second phase, the resulting fragments are claimed to eventually undergo biodegradation. Environmentally degradable plastics based on oxobiodegradation of conventional polyolefins norman c billingham1, emo chiellini2, andrea corti2, radu baciu3 and david m wiles4 1 department of chemistry, university of sussex, brighton, bn1 9qj, uk, and epi europe ltd. Biodegradation of polyethylene and polypropylene j arutchelvi, m sudhakar, ambika arkatkar. The 90% biodegradation level is a very stringent requirement for showing plastics biodegradability. Biodegradation may provide solution to the problem, but not enough is known about the biodegradation process of synthetic plastic and plasticbased foams. Unlike conventional plastics and oxobiodegradable plastics, biopolymer plastics are made by starch usually corn or sugar. Accumulation of plastics in the aquatic environment microplastics plastics and biodegradation of nonhydrolysable plastics resulting in lifetimes of decades or even centuries derraik 2002. In order to support continued sustainable development throughout the world, this problem must be addressed. This article presents an update overview for biodegradation process of some hazardous wastes e.
These fungi secrete enzymes and other cofactors to degrade a wide variety of chemicals. Degradation of plastic materials using microorganisms. The method is designed to yield an optimum degree of biodegradation by adjusting the humidity of the test soil. The microbial biodegradation has been at accepted and process still underway for its enhanced efficiency. Pdf evaluation of biodegradation of plastics researchgate.
This knowledge is useful for the molecular design of biodegradable polymers and for the molecular evolution and breeding of degradation enzymes and microbes. Their bioassimilation is a synergistic interaction between hydrolysis and biodegradation hydro biodegradation. Biodegradationpromoting additives for polymers are increasingly being used around the world with the claim that they effectively render commercial polymers biodegradable. The degradation process of pe, provided as the sole source of carbon and energy in soil microorganisms specifically, showed that small fragments were. In the 1980s, these mixtures were marketed as biodegradable plastics scott 468.
Biodegradation is natures way of recycling wastes, or breaking down organic matter into nutrients that can be used by other organisms. Nondegradable polymers, being resistive to degradation depending on the polymer, additives, conditions etc tend to accumulate as plastic waste, creating a serious. Plastics are typically composed of artificial synthetic polymers. The official journal of the international biodeterioration. Biodegradability of plastics university of florida. These polymers present a problem when composted because the starch. These studies reported on plastic biodegradation i.
Degradation of plastic materials using microorganisms openventio. We found that waxworms, or indian mealmoths the larvae of plodia interpunctella, were capable of chewing and eating pe films. Isbn 9789535111542, pdf isbn 9789535163503, published 20614. Evidence of polyethylene biodegradation by bacterial. However, specific material properties can allow costs reductions in the use or endoflife phase. Biodegradable plastics plastics that will fully decompose to carbon dioxide, methane, water, biomass and inorganic compounds under aerobic or anaerobic conditions and the action of living organisms. Biodegradation of synthetic and natural plastic by. There are several internationally established and acknowledged standards and. Chapter 7 biodegradation of starchcontaining plastics.
The plastics industry trade association degradable additives 5 standards and certifications the specification of time needed for the ultimate biodegradation is an essential requirement for any thirdparty tested and certified biodegradability claim. In addition, the microbial communities associated with the biodegradation environment differ greatly between types e. I spend a lot of time running and walking the gravel and dirt roads near my nebraska home. Evaluation of biodegradationpromoting additives for plastics. Summary tables examples of degradation rates and standards for biodegradation. It allows evaluating the degree of aerobic biodegradation of plastic materials exposed to a marine microbial consortium from seawater. These studies on the biodegradation of plastics have increased our knowledge of degrading microbes, degradation enzymes and their genes, and polymer structures for biodegradation. One major drawback of most polymers used in agriculture is the problem with their disposal, following their useful lifetime. Biodegradation of plastics in natural seawater in laboratory was assessed according to the method astm d66912009. Biodegradation or biotic degradation is a specific property of certain plastic materials that is, of the polymers these materials are made of. There is no reason to change their view after extensive tests in 2012 that plastic products made with oxobiodegradable technology may be recycled together with. It is often said that biodegradable plastic is a licence to litter, but this is no more than a n assertion.
The increase of packaging convenience packaging and other short. Methods for assessment of biodegradability of plastic films in soil. While the words bioplastic and biodegradable plastic are similar, they are not synonymous. Biodegradable plastics degrade as a result of aerobic and anaerobic bacterial activity. In marine environments, microorganisms function as pioneering surface colonizers and drive critical ecosystem processes including primary production, biogeochemical cycling and the biodegradation of anthropogenic pollutants. An attempt has been made to cover the mechanism of biodegradation, the various bacterial and fungal organisms that have. Although the biodegradation of pe by bacterial cultures has been occasionally described, valid evidence of pe biodegradation has remained limited in the literature. In view of this, the biodegradation of plastics has been studied extensively for the past three decades. For most of the biobased and biodegradable plastics there are several suppliers and most plastics are readily available. Ordinary plastics remain unchanged during a composting cycle lasting a few weeks and unless removed from the compost, they will remain in the natural environment.
Aerobic biodegradation is the conversion of plastic material into carbon dioxide, water, and biomass i. Polycaprolactone, pcl, an external file that holds a picture. Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. These plastics were quickly accepted by consumers but soon came under harsh scrutiny. The growing use of plastics in agriculture has enabled farmers to increase their crop production. Plastic can degrade by a variety of mechanisms such as chemical, thermal, photoxidation and biodegradation, all of which take an extremely long time depending on the molecular weight of polymer, it could take up to years for some types of plastics to degrade microorganisms can also play a vital role in this process, as over 90 genera of bacteria, fungi and actinomycetes have the. An example where the rate of biodegradation is important and highly limited is compostable plastics. Degradation rates of plastics in the environment acs publications. Plastic waste might eventually end up in composts along with other biodegradable waste. Bacterial degradation of synthetic plastics explore to. Department of agriculture, peoria, il 61604 plastic. Get a printable copy pdf file of the complete article 1.
1330 973 1445 921 35 1428 1034 1459 207 1083 220 532 1514 1049 622 905 188 578 937 1238 918 81 341 1044 803 75 1193 1146 1130 1130 1288