Fungi are commercially used in the production of some common foods, chemicals, acids, enzymes, hormones and drugs of pharmaceutical value using the fermentation technology. The success of any fermentation is dependent on obtaining a suitable fungal strain and then, on manipulating its biological systems by genetic modification for economic reasons. The fundamental techniques for accomplishing this have been mutagenesis, gene transfer and genetic recombination, followed by selection for desired characteristics.
Although biotechnology has been used some form for centuries, it has undergone a revolution in the past few years through the advent of some artificial techniques, such as gene manipulation in a laboratory setting, and gene cloning-developed for making recombinant DNA. Such techniques together constitute the genetic engineering or recombinant DNA technology, by which the genotype of an organism can instead be modified in a directed or predetermined way.
In natural recombination process, the exchange of genes occurs between closely related organisms but via laboratory manipulations, called genetic engineering, genes can be transferred between unrelated organisms.
The genetic engineering or recombinant DNA technology has revolutionized the study of gene structure, and our knowledge of living organisms and our ability to change them.
The basic technique of recombinant DNA technology is quite simple: DNA is extractor from a donor animal, plant or microbe and cut into fragments by specialized enzymes. A desired gene which is a segment of the donor DNA is then introduced into a host, resulting in recombination DNA that combines genes from two different sources. When a gene is expressed, DNA is transcribed to produce RNA; mRNA is then translated into protein which can be harvested and used for a variety of purposes.
At first the only host available was the bacterium E. coli. With this host much information of value was obtained about the genes of many donors, including several fungi and humans.
Subsequently, ways of using yeasts and moulds as hosts for gene cloning were devised. During the last few years, the practical application of fungi expanded almost beyond imagination with the development of these techniques. Fungi are now being used to produce a number of natural proteins, hormones, vaccines and several enzymes. These products have great potential for medical use.
Recombinant DNA techniques are underway in order to enhance the production of antibiotics, antifungal compounds.