TE.CHNOLOGY > SCIENCE AND INDUSTRY> PLASTICMOTHER NATURE

However, tbe....,enzymesthis second strain developed were different from the nylonase enzymes thefirst group developed. Further studies located the exact genetic mutation that enabled the secondgroup to digest the nylon.

In 1975, a team of Japanese scientists discoveredcolonies of bacteria living in ponds that containedwastewater from a nearby nylon factory.Remarkably, these bacteria were able to digest nylonbyproducts. What's so remarkable about that? Thebacteria were digesting substances that don't exist innature!

Like all plastics, nylon is synthetic-it was inventedby a chemist in a laboratory in 1935. The threeenzymes the bacteria used to break down the nylonwere also completely new, and very different fromthe enzymes produced by similar bacterial strains.They were so new that they required a new name:nylonase.

The discovery prompted further experimentation. Insubsequent studies, scientists placed normalbacteria in an environment that contained fewnutrients other than nylon. They found that thebacteria quickly evolved nylon-decomposing abilities.

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All of this seemed to reinforce the ideas about natural selection that Charles Darwin first devised 150years ago. Bacteria mutate frequently, and this one particular mutation-the ability to digestnylon-allowed bacteria to grow and thrive in an unfamiliar environment. Since the mutation gave amajor advantage to certain individuals within the population, it was passed on to future generationsuntil entire populations of bacteria exhibited the new trait!

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TE,CHNOLOGY > SCIENCE AND INDUSTRY> PLASTICREAL LIFE

In some countries, they're foundeverywhere. For example, in China,the bags are known as "white pollution," while South Africa's Minister for the Environment andTourism jokingly referred to them as his country's "national flower."

Plastic shopping bags, like the onesyou find in the grocery store, are amajor problem for the environment.They don't decompose in the earth,and they're allover the place.

Consumers in the United States gothrough 100 billion of them per year,and it's estimated that between 500billion and 1 trillion are usedworldwide every year. Even whenthese bags are recycled, the ones thataren't wind up creating massive litterproblems.

Often, discarded plastic bags wind up in the ocean, where they wreak havoc on all forms of life, fromsingle-celled plankton to enormous baleen whales. One study estimates that 100,000 marinecreatures dje.1rbm eating plastic bags every year.

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A number of countries and municipalities have taken direct action to cut down on the number ofplastic bags being used. Some nations, including Ireland, South Africa, and Israel, have imposedtaxes on the bags. The taxes help pay for environmental clean-up and encourage shoppers to usedifferent types of bags.

Some areas have banned plastic bags entirely. They're illegal in Bangladesh, Bhutan, and Zanzibar.China banned them in 2008, France is set to do so in 2010, and citywide bans are in effect in dozensof places across the globe.

As an alternative, many retail stores are starting to offer paper bags. (Paper bags were once all therewas, until plastic became way cheaper to produce.) But the most environmentally friendly option is tobring your own reusable bag instead!

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