Jeans are the most versatile, lived-in, and best-loved item of clothing in history. It's hard to believe that annual sales of jeans make up part of a $700 Billion global industry! Yes, jeans have been BIG business in recent years. Jeans have clearly come a long way since their work-wear roots and are now a well established wardrobe staple. In the UK alone, consumers bought no less than 86 million pairs of jeans in 2007, an increase of over 40% in the last five years. What is more, spending on jeans reached a massive 1.51 billion by the end of 2007, a 4% increase on the 1.45 billion spent in 2006 and some 32% up on 2002 figures.

In the US, an estimated 450 million pairs of jeans are purchased every year; making them a staple of the American wardrobe. Indeed, jeans are the most widely produced piece of apparel in the U.S. Jeans have long been a cyclical market being driven in the main by factors such as employment conditions, productivity, fashion trends, lifestyle factors, and celebrity endorsements. Manufacturers and retailers are constantly challenged to maintain the market by staying on top of fads, changing tastes and consumer desires for different styles of jeans. The U.S. jeans market is stable in 2008 after a profitable surge in revenue earlier this decade. Although sales are not growing at comparable rates, the market remains in good shape. A failing housing market and general recessionary fears have slowed this market somewhat, but consumer survey results and a booming premium denim segment illustrate that jeans remain an essential component to U.S. consumer wardrobes.

Jeans manufacturers are responding by offering stylish jeans at all price points and at retail outlets ranging from mass merchants to specialty boutiques.

Regardless of the color or style, jeans are subjected to some sort of wash treatment to give the fabric a softer, smoother feel. To produce "stone washed" jeans - as the name implies - freshly dyed jeans are loaded into large washing machines and tumbled with stones. Adding pumice stones gives the additional effect of a faded or worn look. The pumice abrades the surface of the jeans like sandpaper, removing some dye particles from the surfaces of the yarn. Pumice has been used since the introduction of stone washed jeans in the early 1980s.

However, stone washing with pumice has some severe drawbacks. The quality of the abrasion process is difficult to control: Too little will not give the desired look. Too much can damage the fabric, particularly at the hems and waistbands. The outcome of a load of jeans is never uniform, with a significant percentage always getting ruined by too much abrasion. The process is also nonselective. Everything in the washing machines gets abraded, including the metal buttons and rivets on the jeans as well as the drum of the washing machine. This substantially reduces the quality of the- products and the life of the equipment, and increases production costs.

Acid washing jeans avoided some of these problems, but came with added dangers, expenses, and pollution. Environmental regulations have put intense pressure on the textiles industry to generate less pollution. Treating the wastewater and disposing of the sludge (i.e. used pumice or neutralized acid) represents a growing portion of the production costs for a pair of jeans.

To overcome these drawbacks, a technique known as "biostoning" was introduced in Europe in 1989 and then quickly adopted in the US the following year Biostoning relies on the action of enzymes to selectively modify the fabric surface. Enzymes have been used in the textiles industry since the turn of the century to remove starchy and waxy residues from raw materials and to give fabric a uniform finish. The enzymes used in biostoning are known as "cellulases." (Note on scientific lingo: The ending "-ase" at the and of a word usually means that the molecule is an enzyme).