Growth parameters of the thermophilic hydrocarbon utilizing strains Aspergillus fumigatus and Mucor lusitanicus in n-alkanes (KW)- and glucose (GIc)-medium in standing and fermenter cultures were investigated. The temperature limits for growth were dependent on the medium composition. The temperature range for sporulation was smaller than for the hyphal growth. Both strains were cultivated on carbon limitation with subsequent determinations of n-alkanes glucose, ammoniumsulfate-nitrogen, phosphate-phosphorus and the trace elements Mn, Cu, Zn and Fe. A method for estimation of hydrocarbon utilization was developed. In a medium containing a mixture of n-alkanes and glucose as C-sources the strains utilized at first glucose. Both the strains excreted monocarbon acids with a low carbon number into the culture liquid. The results were discussed.
The effect of manganese sulphate in the culture media of five nitrogen-fixing bacterial samples, isolated from Allahabad soil, was studied. All the nitrogen fixers studied here show an increase in the nitrogen fixation at a particular concentration of manganese sulphate in the culture medium and also a slight increase in the rate of respiration, as indicated by the consumption of carbon by the microorganisms.
Chaetomium globosum, C. spirale, Fusarium moniliforme, F. oxysporum Orthaceras, F. oxysporum Schlecht, F. semitectum, and F. solani were found to be able to decompose cellulose of filter paper. Total cell carbohydrate of the fungi under examination contained about 40 % of their substrate cellulose.
Rice powder-corn steep (RC) medium proved to be the most suitable among 6 nutrient liquid media for both aflatoxin formation and mycelial growth by the Aspergillus flavus strain No. 182, isolated locally. The production of aflatoxins by the mould was studied in relation to some cultural conditions on RC medium. Highest aflatoxin yields (2527 microgram/50 ml) by A. flavus were attained using rice (5%, w/v) + corn steep (4%, w/v), at initial pH level of 4,25 degree C and 6 days incubation. The initial pH levels at either extreme of the range used (3 and 11), and temperatures of incubation below 20 degree C or above 40 degree C were inhibitory to mould growth and aflatoxin formation. The ratio of aflatoxin B1 to G1 varied with different cultural conditions. The aflatoxin content of the mycelia highly exceeded that of the culture filtrates.
A tropical semi-arid soil was fractionated by successive wet sieving at 200 μm and 50 μm in order to separate two light fractions, two mineral fractions, and one organo-mineral fraction. Each fraction was incubated separately for N mineralization.
There is a deficiency of protein sources, and therefore great efforts are being made towards utilization of petroleum fractions for production of single-cell protein. Most active strains which attack petroleum products are yeasts and bacteria. Production of single-cell protein by yeasts is preferable as yeast cells are easily to be ground and larger than bacterial cells. The main petroleum fractions used in single-cell production are hydrocarbons, especially those containing C12 – C22. Chemical and biochemical conditions controlling fermentative production of single-cell protein are reported. Recovery and purification of cell biomass are also given.
