AB - ln recent years there has been an increasing interest in the possible application of microorganisms for the production of fine chemicals. [...] This thesis reports the results of studies in which various physiological and biochemical aspects ofdihydroryacetone (DHA) and glycerol synthesis and utilization by the methylotrophic yeast Hansenula polymorpha were investigated. The results provide further iasight into the regulation of methanol, DHA, and glycerol metabolism in thisyeast, and a firm basis for further studies aiming to optimize strain properties and physiological conditions for DFIA production up to industrially interesting levels. ...Zie: Summary
derived from hair, both human and animal, or feathers. Can be synthetically produced from .
a compound produced from .
acid produced by the fermentation of whey, cornstarch, potatoes or molasses.
enzyme derived from fungus of yeast. It prevents lactose from being broken down into glucose and galactose. It is used in the dairy industry for people who are lactose intolerant.
milk sugar. A type of sugar only found in milk.
fat extracted from sheep's wool.
fat surrounding the stomach and kidneys of the pig, sheep and cattle.
the fresh berries and leaf extract of the laurel tree.
constituent of vegetable fats, especially coconut oil and oil. Derivatives are used as a base in the manufacture of soaps, detergents and .
compound usually produced from coconut oil (which is naturally high in lauric acid) or from a petroleum based version of lauric acid
tanned hide (mostly from cattle but also sheep, pigs and goats etc)
fatty substance found in nerve tissues, egg yolk, blood and other tissues. Mainly obtained commercially from soya bean, peanut and corn
porous rock formed over thousands of years from the compression of shells and bones of marine animals.
enzyme from the stomachs, tongue glands of calves, kids and lambs. Can also be from derived from plants, fungus or yeast. It breaks down fat to glycerol and fatty acids.
substance of deep yellow color found in egg yolk. Obtained commercially from marigold.
Saccharomyces cerevisiae glycerol biosynthesis
Glycerol is a sugar alcohol produced as a by-product of the ethanol fermentation process by Saccharomyces cerevisiae. In wines, levels between 1 and 15 gll are frequently encountered and the higher levels are thought to contribute to the smoothness and viscosity of wine. Glycerol and ethanol levels are inversely related, which may add an additional favourable attribute to wine. The metabolic pathways involved in glycerol synthesis, accumulation and utilisation by yeast are now better understood since a number of the genes involved in glycerol metabolism have been cloned, sequenced and their functions established. These fundamental studies now permit the glycerol levels produced by yeast to be raised by either the specific control of the culture conditions or by the manipulation of the genetic and molecular properties of the yeast. In some instances, the level of glycerol produced under laboratory conditions has been significantly raised. However, a number of undesirable by-products also accumulate during the fermentation and an improved understanding of the glycerol metabolic flux is required before wines with a consistently elevated glycerol concentration can be produced.