Food colouring now represents a $1.2 billion global market, with natural colours capturing 31% of the food market, but growing at a rate of 5%. However, these natural colours are largely plant extracts that have the disadvantage of variability and seasonal supply. Thus, we have been screening pigment-producing microbes from the New Zealand environment in order to find potential organisms to be used as pigment production factories.
The fungi are a diverse group of microbes, including the moulds which cause agricultural damage and food spoilage, as well as organisms which provide useful bioactive molecules. Currently, we are forced to use toxic synthetic chemicals to control problematic fungi. We have discovered a natural fungicide that is effective against many problematic fungi, with potential applications the in food and pharmaceutical industries.
New Zealand Sauvignon Blanc is considered one of the best in the world due to its unique aromas. Volatile thiols are the group of compounds responsible for the different fruity aromas in Sauvignon Blanc wine. There is an ongoing debate about how volatile thiols are produced in the wine because they are not initially present in the grape juice, but develop during fermentation through yeast metabolism. Recent research findings have cast doubt on the proposed biochemistry of thiol conversion, to the point where the identification of ‘thiol precursors’ in juice is now in doubt. In this project, we are trying identify metabolites in the grape juice that correlate with high levels of thiols in final wine through metabolomics.
Candida albicans is a human commensal fungus that can be isolated from approximately 70% of the healthy population. In the majority of cases C. albicans is harmless, however, if the person is immunocompromised, it can be an opportunistic pathogen. C. albicans is the fourth leading cause of nosocomial bloodstream infections, with an attributable mortality of 37-44% in severely immunocompromised patients. C. albicans have the remarkable ability to grow in several distinct morphological forms: yeast, hyphae, and pseudohyphae, according to environmental conditions. The ability to switch rapidly from yeast to filamentous growth or vice versa in response to certain environmental cues is considered to be a critical virulence factor for this fungus. We aim to unravel the metabolic pathways essential for C. albicans morphogenesis using metabolomics and metabolic flux analysis.
One of our main objectives is to explore the metabolic response of E. faecalis to oxidative stress. Reactive oxygen and nitrogen species play significant roles in immune defence and has also been implicated in contributing to the bactericidal activities of antibiotics. Thus, the virulence of E. faecalis has profound dependence on its ability to tolerate oxidative stress. In our lab, we are examining how the bacterium tolerates oxygen and sub-lethal concentrations of hydrogen peroxide by measuring metabolite levels and metabolic flux distribution. These are complemented by gene knock-out experiments to validate metabolomics and fluxomics findings.
Our laboratory is constantly working on improving the quality and the time spent on processing metabolomics data-sets. As a result, we have developed R packages able to process and interpret metabolomics data-sets in a high throughput manner. In this section you can find more details about the tools we have developed and also links to download them. All the tools available here are constantly under development and feed backs are always welcome.
The effect of audible sound frequencies on the cell metabolism in a new area of interest in our laboratory. We have shown that different audible sound frequencies applied to a yeast cell produces significantly different metabolite profiles and, consequently, different activity of metabolic pathways. If we understand how sound affect the cell metabolism and which metabolic pathways are affected by specific sound frequencies we may be able in the future to use audible sound waves to control cell growth and physiology, increase product yield, inhibit co-product formation and improve productivity of industrial fermentations.