HAU gets patent for Poly hydroxy butarate (PHB) : A green alternative to plastics

Haryana Science & Technology

Haryana Agricultural University (HAU) gets patent for eco-friendly biochemical poly hydroxy butarate (PHB).

Facts :

Scientists of Chaudhary Charan Singh Haryana Agricultural University (CCSHAU) has developed a technique of producing biochemical poly hydroxy butarate (PHB), which is useful in making eco-friendly, cheaper and self-degradable bioplastic.
This technique has been granted a patent by the Patent Office of the Union Government.
Vice Chancellor Prof KP Singh said that a team of scientists of molecular biology, biotechnology and bioinformatics department, led by Dr Virendra K Sikka, had produced the high-value PHB by molecular manipulations of strains of eco-friendly microorganism rhizobium species.
“The PHB can be processed along with additives, like starch, to convert it into mouldable low density bioplastic which is fully biodegradable.
The blends of PHB with conventional plastics can be an easy means to tackle the environmental hazards arising from polyethylene.
As far as the cost of PHB produced with this technique is concerned, by combining the cost of diverse kinds of inputs involved in PHB production and its harvesting/isolation it comes to Rs 1,494 per kg, which could be fairly comparable to the non-biodegradable synthetic plastic and considerably cost effective compared to the international prices.
This was the 15th patent granted to the university so far.

Analysis :

Excessive uses of polymer plastics in boundless spheres have resulted in waste accumulation.
There is an urgent need for switching over to compostable and biodegradable plastics that too from renewable resources.
Polyhydroxy-butyrate (PHB) is a unique biopolymer which is biodegradable and most close to plastics which is miscible with the conventional plastic. The adaptation and commercialization of PHB depend upon its ready availability in a pocket-friendly manner.
This potential in the form of new technology is contributing to fulfil the need of plastic along with the environmental beauty and cleanliness.

Polyhydroxybutyrate (PHB) :

Polyhydroxybutyrate (PHB) is a polyhydroxyalkanoate (PHA), a polymer belonging to the polyesters class that area of interest as bio-derived and biodegradable plastics. The poly-3-hydroxybutyrate (P3HB) form of PHB is probably the most common type of polyhydroxyalkanoate, but other polymers of this class are produced by a variety of organisms: these include poly-4-hydroxybutyrate (P4HB), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polyhydroxyoctanoate (PHO) and their copolymers.
PHB is produced by microorganisms (such as Cupriavidus necator, Methylobacterium rhodesianum or Bacillus megaterium) apparently in response to conditions of physiological stress; mainly conditions in which nutrients are limited. The polymer is primarily a product of carbon assimilation (from glucose or starch) and is employed by microorganisms as a form of energy storage molecule to be metabolized when other common energy sources are not available.
Microbial biosynthesis of PHB starts with the condensation of two molecules of acetyl-CoA to give acetoacetyl-CoA which is subsequently reduced to hydroxybutyryl-CoA. This latter compound is then used as a monomer to polymerize PHB. PHAs granules are then recovered by disrupting the cells.

Properties of PHB :

Water-insoluble and relatively resistant to hydrolytic degradation. This differentiates PHB from most other currently available biodegradable plastics, which are either water-soluble or moisture-sensitive.
Good oxygen permeability.
Good ultra-violet resistance but poor resistance to acids and bases.
Soluble in chloroform and other chlorinated hydrocarbons.
Biocompatible and hence is suitable for medical applications.
Melting point 175 °C., and glass transition temperature 2 °C.
Tensile strength 40 MPa, close to that of polypropylene.
Sinks in water (while polypropylene floats), facilitating its anaerobic biodegradation in sediments.
Nontoxic.
Less 'sticky' when melted