Biotechnology is, perhaps. best defined as the industrial utilisation of biological systems or processes. In sense, therefore, biote(biology ha existed for thousands of years. The most ancient biotechnological art is fermentation. Living micro-organisms have been used for centuries to make curds. condiments, cheese and vinegar, to prepare dough for bread or bhatilras. and to brew alcohol. But today we know much more about these simple processes. With thehelp of powerful microkcopes and carefully done expe;iments in the laboratory, we have come to under tatid that the tiny microbes involved in these processes are small biochemical factories. And they can be used for a variety of purposes, related to health, medicine. food, pollution control ctc.