Synthesised by Living Organisms Essay

Definition of biopolymer:

Biopolymers are of course happening polymers which are synthesised by populating beings. This synthesis can happen either internally within an being ‘s construction, or externally in appropriate conditions. The term biopolymer besides encompasses those polymers which are produced by the physical or chemical use of production environments. However, depending on the term ‘s inception, it does non purely include those polymers produced by biological manipulating. For this ground, it is best to sort such polymers as & A ; lsquo ; partly man-made biopolymers ‘. Through the chemical and physical use of production environments, a big assortment of biopolymers have been synthesised. Each of these freshly developed biopolymers are available with alone and good belongingss, along with the ability to biodegrade and supply a renewable beginning of plastic like stuff.

Reasons why biopolymers may go progressively of import in society:

Petroleum derived plastics have formed an built-in relationship with modern society, supplying a inexpensive, convenient and lasting method for developing legion consumer goods and other merchandises. The negative impacts associated with fictile favour the usage of biopolymers. Such impacts, along with other factors, involve:

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  • An overexploitation of non-biodegradable plastics. These plastics are produced at a rate of over 100million metric tons per year- ingestion forms which have lead to serious jobs refering environmental pollution, waste direction and danger to animate beings.
  • An uncertainness about the future resources of the petrochemical industry. This industry may go disused or bring forth goods excessively expensive for mainstream ingestion.
  • The enterprises of recycling hold failed to do any great advancement over the old decennaries.
  • The recent success of biocompatible plastics which have revolutionised the medical industry.
  • The ability to utilize industrial waste ( such as nutrient waste ) as a substrate for biopolymer production. This has the added benefit of bettering waste use and cut downing other signifiers of pollution and intervention.
  • Burning of electronic waste ( e-waste ) to retrieve the cherished metals contained in french friess and circuits. With the continued exponential growing of the electronics industry, the illegal pattern of in secret firing e-waste releases many toxic gases, particularly if coated in PVC.

For these grounds, much involvement has arisen in the design and development of biodegradable, renewable, practical and economically feasible biopolymers to replace the man-made plastics consumed today. The new age of renewable energy and waste direction have resulted in great accent on the hereafter of biopolymers and the comparative efficiency of their production.

Selected Biopolymer:

PHB is a biopolymer belonging to a group of biopolymers called polyhydroxyalkanoates ( PHA ). It is besides classified as a polyester due to incorporating an ester functional group. PHB is synthesised by the polymerization of ( R ) -3-hydroxybutynl-CoA.

PHB is produced by bacteriums as the consequence of physiological emphasis. During this procedure PHB acts as an energy storage molecule to be used subsequently when other energy beginnings are depleted. The most common signifier of PHB is poly-3-hydroxybutyrate, ( as shown in the above diagram ), nevertheless discussed below are the generalized notes for all PHB isomers.

PHB was foremost discovered in 1925 by Maurice Lemoigne who concluded that bacteriums could bring forth polyesters. However Maurice ‘s find was non officially recognised as PHB until its rediscovery in 1957. This stimulated much involvement in the hereafter of biopolymers, an involvement which has reignited in recent old ages due to the environmental argument and unsure hereafter of the petrochemical industry. Using traditional production methods, up to 80 % of the dry weight of the bacteriums can be composed of PHB.

Properties of the biopolymer

  • 100 % biodegradable in both aerophilic and anaerobiotic environments
  • Biocompatible – the polymer can be of course incorporated into and decomposed by the human organic structure
  • Thermoplastic
  • Piezoelectric – produces an electric potency when compressed 8
  • Low thermic stableness 9
  • Ultra violet opposition 10
  • High runing point 175 & A ; # 730 ; C8
  • Low opposition towards acids and bases 10
  • Transparent and bright
  • High crystallinity – structural agreement 8
  • Stiff 8
  • More heavy so H2O 10
  • Brittle – depends on the degree of crystallinity 8
  • Does non hold concatenation ramifying – it is isotactic ( unvarying construction ) and hence flows good during processing8
  • Is non soluble in H2O – hydrophobic 8
  • Has a low permeable degree ( incursion ) for O, H2O and C dioxide8
Uses or possible utilizations of the biopolymer Relationship between utilizations and belongingss
PHB could go the new stuff for usage in bottles, bags, wrapping, diapers and other disposables where biodegradability is a concern Due to the biodegradability of PHB in both aerophilic and anaerobiotic environments ( both in the presence or deficiency of O ) there is a great inducement for the possible replacing of the polymers derived from petrochemicals. PHB is besides hydrophobic, has low permeableness by O, H2O and CO2, has UV opposition, high thaw point, and is isotactic – belongingss which make PHB a suited replacing for many plastic merchandises.
PHB can be used as a medical tool. These include surgical implants, paces and coatings. In medical applications, PHB is biocompatible with the blood and tissues of worlds and other mammals. The normal metamorphosis of worlds produces the monomer of PHB, ( R ) -3-hydroxybutynl-CoA, and therefore does non reject the polymer ‘s usage as a medical tool. Surgical implants and togss all reabsorb into the organic structure.
In the pharmaceutical industry, PHB can surface capsules and supply slow or controlled drug release. The belongings of biocompatibility allows this procedure to happen. Besides, a low permeableness for O2 and H2O allows it to be released easy.
The electronics industry presently burns the plastic ( normally PVC ) coatings around french friess and circuits to retain cherished metals. PHB could supply an option which prevents toxic gases being released by this pattern. Due to the belongings of biodegradability, particular intervention installations could be established to pull out the cherished metals in an environmentally friendly mode.

Potential benefits of the biopolymer to society and the environment

Environmental impacts:

  • Recycling plastic as an option to environmental pollution and landfill normally requires more energy compared to making new plastic. A biopolymer with the ability to biodegrade, such as PHB, removes the demand to see the less energy efficient recycling method.
  • Burning waste plastic to tackle energy is an option towards to landfill issue, but this releases toxic gases and additions C dioxide concentration in the ambiance. Conversely, biological polymers form portion of a natural rhythm whereby C dioxide and H2O are used during photosynthesis and released during natural decomposition.
  • The ability to synthesize PHB from a broad assortment of C rich beginnings means that a secondary usage or market can be found for some waste merchandises. Using substrates such as industrial nutrient waste and molasses from sugar processing reduces the demand for the intervention and disposal of such wastes.
  • The complete conversion to PHB from normal crude oil derived plastics would cut down landfill volumes by about 20 %, given this is the per centum composing of plastics in our trash. This would cut down overall volumes of pollution.

Social impacts:

  • PHB and other biopolymers have revolutionised the medical industry. PHB is biocompatible with human blood and tissues, and readily resorb into the organic structure objects such as implants and weaving. The biopolymer can besides be used as a stuff for slow releasing drugs. Improvements in this field are inevitable.
  • Petrol derived plastics can be carcinogenic. Examples include those incorporating benzine and vinyl chloride. PHB is a safer stuff for usage in containers and imbibe bottles where this is an inconclusive concern.
  • Reducing the volume of landfill by 20 % has the societal benefit of increasing overall domestic, commercial and industrial land usage. It besides reduces the populace & A ; lsquo ; eyesore ‘ the landfill creates.
  • Production of PHB utilizing nutrient substrates can hold negative social impacts. A higher demand for substrates which form the basic diet of developing states may cut down the ability of these states to buy this nutrient. Such a effect would decline the nutrient deficits of these developing states.

HSC Chemistry

Assessment Task 1: Biopolymers

Current jobs with the biopolymer

HSC Chemistry

Using PHB as a replacement stuff for crude oil derived man-made plastics would be well more and offer no existent public presentation advantages other than its biodegradability. In the production of PHB four major factors influence overall cost:

  • the monetary value of the substrate
  • the effectual output achieved from that substrate
  • the monetary value of other input factors
  • boring production processs such as the demand for a pure civilization of alcaligenes eutrophus

The cost of reaping the PHB straight from alcaligenes eutrophus costs about $ 8/kg. This is well more than the $ 1/kg production cost for most oil based plastics. These high costs are reflected in the comparative costs of different substrates. The cost of the petrochemical substrate for polypropene is US $ 0.185/kg of polypropene. This is a big fluctuation compared to the monetary values of different PHB substrates given in the undermentioned tabular array:

Substrate effectivity based on substrate costs and output of PHB


Monetary value of substrate ( US $ /kg )

Output ( kg/kg of substrate )

Substrate Cost ( US $ /kg of PHB )

Glucose 0.493 0.38 1.350
Sucrose 0.295 0.40 0.720
Methanol 0.180 0.430 0.420
Acetic Acid 0.595 0.380 1.560
Ethyl alcohol 0.502 0.500 1.000
Molassess 0.220 0.420 0.520
Cheese whey 0.071 0.330 0.220
Corn Starch 0.220 0.185 0.580
Hemicellulose 0.069 0.200 0.340

In add-on to the economical restraints of PHB, assorted mechanical issues are besides evident:

  • PHB is stiff and brickle compared to polyethylene and polypropylene. This has hindered its broad credence as a practical replacing for these stuffs. Brittleness is straight related to the grade of crystallinity in the stuff.
  • At room temperature, over clip, secondary crystallization occurs and the stuff becomes more brickle.
  • The polymer ironss degrade during processing
  • The consequence of the mass production of PHB on the environment has non been exhaustively investigated. While the stuff is biodegradable and renewable, major environmental effects non yet identified may be.

Properties/production processes which need further research

The chief waies of betterment and research into modifying PHB and/or its production procedure can be classified into two classs:

HSC Chemistry

1. Methods which involve the physical or chemical use of production environments:

  • Adding lubricators and plasticizers to forestall degrading of ironss during processing.
  • Researching new bacteriums which of course produce plasticizers along with the biopolymer to turn to the issue of crispness. Such advancement would straight cut down the production costs as the plasticizers otherwise added are expensive.
  • Suppression of the secondary crystallization that occurs over clip
  • Making merchandises that are programmed degradable – a biopolymer that allows you to command when and how it degrades. This will see that the biopolymer remains practical while still in usage.
  • Investigating the influence of additives on PHB degrading and degree of crispness
  • Increasing the productiveness of treating techniques such as:
  • Bulge: the procedure in which blends are assorted to make a unvarying merchandise
  • Injection molding: the procedure of shooting the liquefied polymer into a mold to solidify
  • Investigating which dissolvers used in the extraction procedure are most productive and efficient
  • Distinguishing methods which decrease the production clip. Time means money, and the clip taken by the bacteriums to bring forth PHB is an economical factor impeding its commercial usage.

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