Utilization of waste products of dehydrated onion industry for production of fodder yeast by Saccharomyces cerevisiae.

One strain of Saccharomyces cerevisiae was selected from different yeasts, isolated from black strap molasses. This microorganism was cultivated on seven fermentation media for the production of protein. Medium I exhibited the highest potentiality for formation of protein. Therefore strain 1 of S. cerevisiae and medium I were used for further studies in the formation of protein. Factors controlling production of protein were explored. The required incubation period for the fermentation process was 72 hrs, while the initial pH value of the medium was 6.0. Sucrose supported the microorganism for higher production of protein (40.96%), while the best concentration of sucrose was shown to be 10.0 g/l. The best inorganic and organic nitrogen sources for protein formation were (NH4)2HPO4, (NH4)3PO4 and yeast extract, respectively. The best concentrations of (NH4)2HPO4 and yeast extract, supporting protein formation, were 5.0 g/l and 10.0 g/l, respectively. Addition of MgSO4, ZnSO4, ferrous ammonium sulphate, copper sulphate, biotin, Ca-pantothenate, thiamine, pyridoxine, and inositol to the synthetic medium did not markedly influence high level of protein formation. Glutamic acid was the best amino acid, supporting protein formation by S. cerevisiae. Onion juice was found to be a good medium, after deletion of inhibitory volatile sulphur organic compounds, for the production of protein by S. cerevisiae. Addition of (NH4)2HPO4 to the best concentration of onion juice assisted the onion medium in production of fodder yeast, containing high level of protein. Addition of MgSO4 to onion juice and (NH4)2HPO4 did not increase the total nitrogen of the biomass. Fodder yeast, produced by onion juice medium, contained more valuable ingredients than fodder yeast, produced by synthetic medium.

Detection and spectrophotometric determination of cobalt with dimedone dioxime.

Dimedone dioxime forms coloured complexes only with cobalt, nickel and copper ions in alkaline solution. Acidification and solvent extraction enables cobalt (1-50 mug) to be determined spectrophotometrically without interference. A specific spot test for cobalt is based on the same reaction.