New Researches in Biotechnology - Facultatea de Biotehnologii ...

Proceeding of the 4 rd International Symposium“NEW RESEARCH IN BIOTECHNOLOGY” USAMV Bucharest, Romania, 2011If Monascus purpureus was developed on grain milk, the content of citrinin inculture media which result after fermentation is 386 mg/L [4-5]. If the same strain wasgrowth on potato-glucose medium, the citrinin content at the end of fermentation is lessthan 1.1 ppm.If we reffering to raw materials used in food industry, maximum concentration ofcitrinin find in cereals was 224.6 ng/g.In some products used in animal fodder, sometimes citrinin concentration is bigger that 405ppb [5].In the case of Monascus sp.1 which develop in culture media with dextrose, thestudy regarding the content of citrinin in liquid culture media indicate a maximumconcentration at 96 h of biosynthesis, when the content of citrinin from the system attain7.72 ppm. After 120 h of biosynthesis, the content of citrinin from the system decreased to3.5 ppm (figure 17) and continue to decrease until 2,68 ppm at 240 h of biosynthesis.This fact is positive because the maximum concentration of red azaphilones wasattained after 200h, when in the system the citrinin concentration is less than 2.7 ppm. Inthis case results obtained are comparable with citrinin content from juice or wine.In the case of strain Monascus sp. 2, the analysis indicate a maximumconcentration of citrinin of 24.48 ppm, at 120h of biosynthesis. After 168h the content ofcitrinin from the system decreased at 3.39 ppm figure 18). After 10 day of fermentation, thecontent of citrinin from the system decreased to 2.2 ppm.If we compare the time at which we obtain the maximumum content of azaphylonewith time in which we obtain the minimum content of mycotoxin, we obtain an optimaltime of biosynthesis situated in the range of 200-220h.4. CONCLUSIONGood results are obtained in the case of biosynthesis of azaphilone on dextrose culturemedia using Monascus sp.1 or Monascus sp.2 as strains. In the last case, the maximumconcentration of red azaphilones are obtained after 170 h of biosynthesis, (OD =1 for redazaphilones) when the content of citrinin is situated under 3 ppm. These results recommendthe strains Monascus sp.1 and Monascus sp.2 to obtain food additives (pigments) insubmerged culture media with dextrose.ACKNOWLEDGEMENTS. The work was financially supported by the projectPOSDRU/89/1.5/S/52432 from 1.04.2010 - Institutional organization of a postdoctoralschool of national interest "Applied biotechnology with impact in the Romanian economy";the project was cofunded by the EU Social Fund in the framework of the SectorialOperational Programme 2007-2013 for Human Resources Development88