Issues and advances in the use of transgenic organisms for the production of thaumatin, the intensely sweet protein from Thaumatococcus danielli.

The thaumatins are a class of intensely sweet proteins isolated from the fruit of the tropical plant Thaumatococcus danielli. Thaumatin is approved for use in many countries and has application as both a flavor enhancer and a high-intensity sweetener. The supply of naturally occurring thaumatin is limited, which has prompted extensive research into its synthesis via transgenic organisms. The gene encoding thaumatin has been introduced into various microorganisms under transcriptional control of heterologous promoters. Yields to date have been low, but the factors governing more efficient microbial production have been identified. Continued research should allow microbial yields to be improved to commercially viable levels. The unique properties of thaumatin as a food additive could well be exploited by the food industry. Alternatively, the thaumatin gene could be engineered directly into selected fruit and vegetable crops to improve their flavor and sweetness.