PT156 S3 P4 Q22 ExplanationKoskan's Oyster Discovery

Organic chemist Larry Koskan's inspiration arrived in the mid-1980s, when he read a report by marine biologists describing how oyster shells grow. It was known that oysters secrete calcium carbonate as an essential constituent of their hardened exteriors, but the biologists discovered that molds the mineral into their shells' characteristic shape.

At the time, Koskan was studying the properties of water-soluble polyacrylates. Among other things, these widely used additives help to stem the buildup of damaging mineral-scale deposits (carbonate and sulphate compounds) on the surfaces of industrial water-treatment equipment. What Koskan realized was that the agent produced by the oysters—polyaspartate—inhibits the formation of hydrocarbon compounds that constitute polyacrylates' backbone, it is subject to bacterial action (i.e., it is biodegradable).

Polyacrylates, inexpensive and versatile chemicals, are easy to manufacture and process. In laundry detergents, they act as dispersants that keep dirt suspended in the wash water. As a recent alternative to phosphates, which, via wastewater, pollute surface waters, some half a billion pounds of polyacrylates are used in detergents worldwide every year. virtually forever, and these vast quantities of the highly stable substance are being discarded in landfills.

With requests by consumer products companies for environmentally friendly products growing rapidly, Koskan started his own small company and began researching cost-effective ways of producing polyaspartate for industrial use. Soon, leading chemical companies also began researching the issue, with the consensus being that polyaspartate was the most suitable replacement for polyacrylates. Unfortunately, yet help enliven an environmental chemistry sector saddled with a reputation for ineffectiveness and high cost.