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Shrimp Shell Chitin – A New Eco-friendly Material Replaced for Plastic

Shrimp shell chitin is a new eco-friendly material for nature and human life. Each year, the food industry generates the amount of 6 to 8 million tons of waste shrimp and crab shells. Scientists in the US are considering a solution to utilize it to make chitin and chitosan, which can be plastic substitutes.

shrimp-shell-for-chitin
Figure 1: Chitin from shrimp shells helps to reduce the environmental burden from plastic waste

Bioplastics and environment retreat

Plastic waste is one of the human headache. Plastic waste in landfills continues to accumulate. Humans have produced over 8 billion tons of plastic waste from a variety of industries starting in the 1950s. We just successfully recycle 10% of plastic waste. Most of it stays in the landfill for a long time due to hard decomposition of plastic in nature. Besides that, humans dumped plastic waste into the ocean environment, threatening the safety of a wide range of marine life.

Scientists from the USA and Canada think it’s time to solve two troublesome problems that are plastic and waste shells of shrimp and crabs at the same time. The hard shells of lobsters, crabs, or shrimp all contain chitin – a material that, along with a chitosan derivative, can produce biodegradable plastics in weeks or months, instead of centuries like regular plastic.

But the challenge is how to collect enough pure chitin and chitosan from shrimp shells to make the most cost-effective bioplastics. John Keyes, general manager of Mari Signum Company in Richmond VA, thinks that the key is creating environmentally friendly chitin.

Narrow market share for shrimp shell chitin

What is Chitin?

Chitin is one of the most abundant organic materials in the world, second only to cellulose. Not only shrimp shells, but chitin is also abundant in insects, fish fins, mollusks, and molds. Like plastic, chitin is a polymer-a chain of molecules. The combination of many repeating small units forms chitin. The structure of chitin is a linear form of amino sugar joined together. Chitin and Chitosan are antibacterial, non-toxic. They are used in cosmetics, wound healing, and swimming pool water treatment, and other applications.

Difficulties in manufacturing chitin.

Currently, a number of companies around the world are also making research efforts to launch chitin products on the market which is environmentally friendly. Cruz Foam – a business in Santa Cruz, California, USA has started manufacturing surfboards from chitin, although the company specializes in manufacturing sponges used in packaging goods. Polystyrene foam, a common ingredient in surfboards and food packaging, takes 500 years to biodegrade. Cruz Foam co-founder Marco Rolandi claims the Cruz Foam product biodegrades quickly based on an at-home test. He put Cruz Foam in compost behind the house. A month later he discovered that there were live earthworms in this product. While surfboards or eco-friendly bandages are valuable, they are only products for a very narrow niche.

Production of shrimp shell chitin is not easy

Technically, extraction of chitin requires a lot of corrosive chemicals. shrimp shells contain 15 – 40% chitin. To obtain pure chitin, manufacturers have to remove protein and calcium carbonate in the shells. People mostly use a strong acid such as hydrochloric acid to remove calcium carbonate completely from the shells. The reaction releases carbon dioxide and sodium hydroxide.

The production of chitin is costly and need hi-tech equipment. To produce 1 kg of chitin, we need 10 kgs of raw shrimp shells, 6 kgs of thermal coal, 9 kgs of hydrochloric acid, 8 kgs of sodium hydroxide, and 330 kgs of freshwater. Moreover, we need another 200 kgs of freshwater to refine chitin. During manufacturing process, manufacturers need to add alkaline into the chitin. Therefore, they have to invest in very expensive anti-corrosion chemical reactors, along with wastewater treatment technology and carbon dioxide emissions.

Pierre-Olivier Morisset, a reseacher of the Merinov Research Center in Canada, said that people were more concerning on environment safety. Therefore, they are working to figure out how to increase the production of chitin by long-chain polymer method and protecting environment at the same time. However, developing green technology is not simple. Seafood suppliers are also facing economic obstacles. Currently, manufacturers in the US have to pay the garbage weasel unit to collect shrimp and crab shells. In addition, they also have to pay the additional cost of drying shells of shrimp and crabs and transporting them to processing units far away. Therefore, high production cost is also a burden to the chitin industry.

Can Chitin Replace for Plastic?

In conclusion, chitin can’t replace plastic 100%. Firstly, there is limitation in extraction technology. Secondly, high manufacturing cost reduces the desire for buying bio-plastic made from chitin for daily uses. Thirdly, supply of chitin can’t satisfy the high demand. Even if we made all 6 to 8 million tons of the world’s shrimp and crab shells into chitin, it would only meet a small percentage of the total annual demand for plastic. However, chitin from shrimp shells is still a positive direction to contribute to reducing the burden on the environment from plastic waste.

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