Studies on the Role of Rye in the Vienna Process for Yeast Manufacture

A water extract of rye shows an optimum concentration for its effect in causing top growth of yeast. Quantitative studies were reported on the distribution of the yeast throughout a column with various concentrations of the extracts at varying stages in fermentation. Data are discussed relative to the effect of various concentrations of the extract upon the composition of the yeast especially with reference to fat content

Studies of Yeast V - Is Bios a Single Substance

In previous communication (Journal of Biological Chemistry, March, 1922) Fulmer and Nelson showed that the water extract of alfalfa is much richer in the yeast growth stimulant, Bois, than is the 95 per cent alcoholic extract of the same material. In the work here described two extracts were prepared as follows from alfalfa which had been previously extracted with ether. Extract A was an extract by long extraction with absolute alcohol. Extract B was an extract prepared by long extraction of the absolute-alcohol-extracted material with water. Both extracts showed optimum concentrations for maximum stimulation and were about equally potent. Combinations of the two extracts were much more potent than the optimum concentration of either alone. Detailed studies are being made of the properties of the two extracts. Bois is not a single substance but is composed of at least two materials. Bois A is soluble in absolute alcohol and in water. Bois B is insoluble in absolute alcohol and is soluble in water

Three Maxims for the Study of the Nutrition of Microorganisms

I. The relative potencies of two materials cannot be arrived at by the comparison of the effects of the two materials at equal concentrations. Corollary: The effect of treatment upon the potency of a material cannot be determined by the comparison of the treated and untreated material at equal concentrations. II. The relative potencies of two materials at one temperature may not be true for any other temperature. Corollary: Temperature coefficients for the effect of a material must be determined under optimum conditions for each temperature. III. If two materials are to be compared as a source of a protoplasmic constituent the physical chemical effects of the materials must be compensated for

Fermentation Utilization of Cassava. The Butyl-Acetonic Fermentation

The cassava plant belongs to the family Euphorbiaccaee and is botanically known as Manihot utilissima Pohl. It is also called tapioca or manioc although the word tapioca is often used to designate certain forms of cassava products. The cassava is a plant possessing quite unusual characteristics. It has no known pests nor enemies. It grows in most soils, resists extreme droughts, and propagates easily although its growth is restricted to tropical regions. The plant itself is a perennial shrub which attains a height of six to twelve feet at the age of one year. At the base of its stem it produces a cluster of long fleshy roots. The starch content of the fresh cassava root is 25 to 30 per cent; these roots furnish the cheapest source of starch known

Relation of the Structure of Sugars to Their Dissimilation in the Butyl-Acetonic Fermentation

The dissimilation of starch in corn mash by Clostridium acetobutylicum produces butanol, acetone and ethanol, commonly called solvents \u27, in the approximate ratio of 60:80:10, respectively. Although corn mash is the usual substrate, fermentations of certain pure carbohydrates by Cl. acetobutylicum have been investigated previously to some extent. The studies of various workers (3, 4, 5, 6, 9, 10, 11, 12) have shown that a considerable number of sugars are fermented by the butyl organism in semi-synthetic media. The sugar fermentations are somewhat slower than for corn mash, and the final acidities arc somewhat higher with yields of neutral products correspondingly lower. There is some variation in the proportion of solvents produced from the various carbohydrates. Hence, an attempt was made in this investigation to relate the structure of the sugars and the proportions of the solvents formed, by subjecting to the action of the butyl-acetone organism as many of the sugars and polyhydric alcohols as could be readily obtained or prepared. These included thirteen compounds which had not been previously studied in detail, with dextrose and corn mash used for controls

Studies on the Effect of Ultra-Violet Rays upon Yeast Metabolism - I. The Effect of Ultra Violet Light upon the Medium

74. Studies on the effect Exposure of the medium (composed of optimum concentrations of salts and sugar) to ultra-violet light renders it less effective for the growth of yeast. The development of the toxicity increases with duration and intensity of irradiation. An exposure of seven hours through quartz at about l5 cm from a quartz mercury vapor lamp affects the medium in such a way that yeast will show practically no growth in the medium. The work is being continued in order to obtain quantitative results and to explain the phenomenon

Bios, a Resumé

The development of the work on Bios was discussed by considering some typical contributions grouped as indicated below