There would not be enough available, although papain, the enzyme obtained from it, is used in beer manufacture and is a major enzyme used in the food industry.With one or two exceptions, enzymes used in any quantity are obtained from the culture media in which fungi and bacteria have been grown. They were proteases, that is, enzymes that break up proteins, and they did indeed improve efficacy, as judged by tests that are more rigorous than the ones in TV adverts.Where were the enzymes to come from? One source of proteases, the papaya tree, can be ruled out. Thus, some enzymes were found that stood up to the conditions, although the problem was helped because there has been a long trend to reduce temperatures in washing. So the command went out that enzymes were in, and they had better be incorporated into the main wash.

Enzymologists rightly believe that their enzymes are delicate molecules, liable to be disrupted by the conditions found in washing machines.All enzymes are proteins, and we now know that some of them are much more resistant to the alkaline conditions and high temperatures found in the wash than we used to think. Detergent manufacturers thought that housewives would never do this.However, housewives did do it, and enzymes gave a better result than detergent alone. They will be found in the cupboard under the sink, where the detergent packets are kept.At first, the use of enzymes required a pre-soak of the clothes for an hour, prior to washing. There are problems about the scale of supplies - there may not be enough land for the crops - but the products will be waiting.In fact, the first significant development - in terms of cash flow, that is - happened some years ago, and had effects on the whole industry.

It was unremarked, and did not cause panic in the streets, but it has put genetically engineered enzymes into nearly every household in Europe. Nor is everything that comes through the farm gate destined for our table. Much agricultural production is devoted to non-food products. Textiles such as cotton, hemp, silk and wool, as well as perfumes, flowers and vegetable dyes, all come off the land. Oils and fats make soap, and some are still used as lubricants. Starch has myriad uses, while trees give us wood, notably for paper making.

Some farms grow straw for thatching; leather, and buttons made from casein, are two by-products of dairy farming. What is striking about this list is that many substances are in competition with petrochemical products. Cotton competes with nylon, wood is replaced in window frames by PVC, soap competes with detergents, and so on.Petrochemicals are getting scarcer, and more expensive, while we also know that new biotechnology developments take a long time from conception to application. Twenty years would not be unlikely with something as slow- growing as a tree.It is not surprising that longer-term thinkers in applied biotechnology are looking at programmes to replace petrochemical products with those of agricultural origin. The impact of biotechnology will be at least as great in non-food agriculture as in any other biology-based industry.As the cost of petrochemicals rises, products based on biotechnology and agriculture will become more competitive.