Morphological and biochemical studies on some yeasts and fungi

Abstract

The morphological and biochemical studies of the penicillin producing fungi are described; single spore isolations have been made, methods of assay of the antibiotic are described. An attempt is made to correlate the morphological characters of a given strain of Penicillium sp.-colours, growth, colony character, sporulation, etc.-with its antibiotic producing capacity.

The supplemental value of the bran extract and also of extracts prepared from germinated pulses, on the production of penicillin, has been investigated. Encouraging results analogous to those obtained with corn steep liquor have been obtained.

Several strains of Aspergillus niger have been tested for its citric acid producing capacity under standardized conditions. The rate of formation of acid has been determined and the morphological and colony characteristics which distinguish high yielding strains are described. Details of a pilot scale experiment with yields as high as 39 per cent of acid are described.

The nutritional requirements of a specialized type of yeast isolated from a sample of coconut toddy have been determined. It has been found that the organism is an unusually large one, lending itself to a cytological study. The deficiencies in essential nutrients are reflected in the cytochemical picture of this organism and this aspect of the problem has received close and detailed attention. The finding that niacin is an indispensable nutrient for the organism has been made use of in employing the yeast as a test organism for the assay of this vitamin. Conditions under which proportionality between growth and vitamin concentration has been carefully worked out.

Cosmic ray treated yeasts have been investigated with respect to their nutritional requirements. A cytochemical and biochemical study of a strain of distillery yeast treated with a few of the important carcinogens has been conducted.