Red seaweed promises a green alternative to plastic

Red seaweed promises a green alternative to plastic

Subject : Environment

Context:

• National Institute of Ocean Technology (NIOT), Chennai, holds out hope that biopolymers from red seaweed( Kappaphycusalvarezii) incorporated with nanoparticles could substitute plastic in certain applications.

Details:

• The whole seaweed  Kappaphycusalvarezii(containing carrageenan) was used in preparing the bio-nanocomposite film by blending with metal oxide nanoparticles such as zinc oxide, cupric oxide and silicon dioxide. Then its properties were compared with standard refined commercial-grade carrageenan.

Red seaweed or Kappaphycusalvarezii:

• Kappaphycusalvarezii, the elkhorn sea moss, is a species of red algae.
• The elkhorn sea moss varies in size, weight, and age.
• It is a dark greenish-brown hue and can sometimes be deep purple.

Carrageenans:

• Also called carrageenins are a family of natural linear sulfated polysaccharides that are extracted from red edible seaweeds.
• Carrageenans are widely used in the food industry, for their gelling, thickening, and stabilizing properties.
• Their main application is in dairy and meat products, due to their strong binding to food proteins.
• In recent years, carrageenans have emerged as a promising candidate in tissue engineering and regenerative medicine applications as they resemble native glycosaminoglycans (GAGs).
• They have been mainly used for tissue engineering, wound coverage and drug delivery.

What are Biopolymers?

• Biopolymers are natural polymers produced by the cells of living organisms.
• Like other polymers, biopolymers consist of monomeric units that are covalently bonded in chains to form larger molecules.
• Biopolymers derived from any plant-based biomass are renewable, biodegradable, and eco-friendly.

Types of Biopolymers:

• Biopolymers can be classified according to various scales. These classifications are based on their origin, the number of monomeric units, on the basis of degradability, heat response etc. Some of the classifications are:

On the Basis of Type:

1. Sugar-based polymers: Starch or sucrose is used as input for manufacturing. Lactic acid polymers are created using lactose from potatoes, maise, etc
2. Starch-based polymers: Starch acts as a natural polymer, composed of glucose. It is found in plant tissues.
3. Cellulose-based biopolymers: Used for packaging, this polymer is made up of glucose obtained from natural sources like cotton. Eg. cellophane.
4. Synthetic materials: Degradable polymers can be made from synthetic materials obtained from petroleum.

On the Basis of Origin:

1. Natural biopolymers: These are natural biopolymers biosynthesised by living organisms.
2. Synthetic biopolymers: These are polymers made up of renewable materials like polylactic acid which are degradable.
3. Microbial: Biopolymers produced by microorganisms.

On the Basis of Monomeric Units:

1. Polysaccharides: These are carbohydrate chains which are branched or linear: Eg. starch, cellulose, etc.
2. Proteins: Polymers made up of amino acids. collagen, fibrin etc.
3. Polynucleotides: Nucleic acids are long polymer chains composed of 13 or more monomeric units. Eg.DNA, RNA

Examples of Biopolymers:

• These include natural rubbers (polymers of isoprene), suberin and lignin (complex polyphenolic polymers),cutin and cutan(complex polymers of long-chain fatty acids) and melanin.

Usage of Biopolymers:

• Biopolymers have applications in many fields including the food industry, manufacturing, packaging, and biomedical engineering.
• These include bioplastic films for packaging, biomedical scaffolds/grafts, 3D printing ink, controlled drug delivery, biosensor, and microbial fuel cell for electric vehicles.
• Polysaccharide extracts from seaweed — carrageenan biopolymers — are already used by the food industry. But such extraction uses solvents and chemicals, which also generate waste.