Euteco Impianti S.p.a.

Societa' Italiana Resine S.p.a.

Giuliano Cardini

Aldo Zotti

Claudio Rottigni

Continuous process for the cultivation of yeast cells under aerobic conditions in an aqueous growth medium, to which an aqueous nutrient medium comprising a source of assimilable nitrogen and methanol of a source of assimilable carbon is continuously added. The yeast belongs to the species Candida boidinii and the nutrient medium comprises a primary source of assimilable nitrogen consisting of urea and a secondary source of assimilable nitrogen chosen from ammonia, ammonium hydroxide and ammonium salts, the ratio between nitrogen in the primary source and that in the secondary source being from 2:1 to 1:20.

Process for the cultivation of yeast cells

The commercial process of preparing citric acid by submerged fermentation of hydrolized carbohydrates under aerobic conditions with yeasts of the genus Candida, while maintaining the pH value at 5-7 by addition of calcium hydroxide, is improved by submitting the broth obtained from a first fermentation operation to a first centrifuging to separate calcium citrate and then to a second centrifuging to separate the yeast cells. The cells thus recovered are recycled for use in a further fermentation operation. The use of said recycle cells permits higher yields and outputs of citric acid to be obtained in the further fermentation operation.

Process for preparing citric acid by fermentation of carbohydrates

Process for the production of microorganism lysates, comprising subjecting the said microorganisms suspended in water to thermal shock produced by a spray-drying treatment and then subjecting the product resulting from spray drying to autolysis.

Growing community of inventors

Milan, Italy

Giuliano Cardini