LOW-COST PRODUCTION OF PERDEUTERATED BIOMASS USING METHYLOTROPHIC YEASTS

Three strains of methylotrophic yeasts, Candida boidinii, Pichia angus ta (previously Hansenula polymorpha) and Pichia pastoris, were studied for their capacity to grow on methanol in deuterated media. Growth ra tes, determined relative to the extent of deuteration of water and/or methanol, showed that water deuteration was the major limiting factor. After adaptation to deuterium by progressive transfer through media o f increasing deuteration, growth rates were diminished relative to tho se obtained on hydrogenated media of identical salts composition: the two Pichia species retained the highest growth rates (mu = 0.02 h-1) i n the fully deuterated medium. Perdeuterated biomass (16 g) was obtain ed in a 1 liter fed-batch fermentation and the extent of deuteration o f isolated ergosterol has been shown to be 97.5% by mass spectrometric analysis .