Investigate sources of natural colors.

There has been an increasing interest in the food industry in the use of natural ingredients, including naturally sourced colors. Colors are natural when they are derived from biological sources. Microbial-sourced colors already are used in the fish industry to enhance the pink color of farmed salmon. Some natural colorants could potentially be used as antioxidants and nutraceuticals.

Scientists at the University of New South Wales (Cooperative Research Center for Food Industry Innovation, Department of Biotechnology, Sydney NSW 2052 Australia) are investigating microorganisms from different environments as sources of natural colors or pigments. They have collected microorganisms from a range of naturally heated environments, from sea ice in the Antarctic and from foods. Initial studies, centered on the physiology and genetics of pigment production, lay the basis for an understanding of the way in which cells produce pigments.

Scientists intend to genetically alter these microorganisms to alter the amount and type of pigment produced by these cells. Mutants have been isolated which hyperproduce a pigment as well as various colored intermediates. Analysis of the nature of the biosynthetic intermediates suggests that at least one intermediate has commercial potential both as a colorant and as a nutraceutical.

Researchers have carried out fermentation studies to examine the environmental conditions that affect pigment production and the recovery of natural pigments from microbial cells. They are compiling the data from these studies to commercially evaluate the biological production of these natural colors and antioxidants. The conditions are being optimized for the production of pigments from microorganisms from extreme environments by fermentation.

Investigators have developed techniques for the extraction and fractionation of the pigments. They are also analyzing their chemical structures, properties and the biochemical pathways that lead to their synthesis. In addition, the research team is identifying different strains using RNA sequence analysis.

Investigators have developed gene transfer systems in microorganisms. They have developed genetic tools for the isolation of specific mutant types, identified novel genetic elements in pigmented microorganisms, determined the nature of pathway intermediates and identified and manipulated specific carotenogenic genes.

Future research will emphasize strategies aimed at isolating strains that overproduce the pigment or specific colored intermediates, with special emphasis placed on those intermediates with antioxidant and nutraceutical applications. Fermentation studies will continue to define the environmental conditions needed to optimize the production of natural colorants from those isolates. Scientists will examine the genetic basis of pigment biosynthesis and the regulation of these biochemical pathways.

Further information. D. Glenn; phone: [phone]; fax: [phone]; URL: http://www.biotech.unsw.edu.au/foodcrc.