Production of lipase by certain fungal strains. 1. Effect of some cultural conditions

Production of lipase by some fungal strains under the influence of different environmental and cultural conditions was studied. PH 6 was the optimum for most of the tested strains. Five days were the optimum incubation period for F. moniliforme, Mucor circinelloides and P. Funiclosum, while six days were the optimum incubation period for Aspergillus fumigatus, A. terreus and Fusarium soloni. Study of the effect of different concentrations of corn oil on lipase production declared that 0.3% was the optimum concentration for F. Moniliforme and P. Funiculosum, while 0.4% concentration of corn oil was the optimum for A. terreus, F. solani and M. circinelloides. Study of the effect of different nitrogen sources on lipase production revealed that DL-aspartic acid was the best A. Terreus, F. Solani and P. funiclosum, while L-glutamic acid was promotive for F. moniliforme and M. Circinelloides

Production of lipase by certain fungal strains. II. Efect of some additives to the growth medium

Lipase production by some fungal isolates under the influence of certain additives to the growth medium was studied. 1% concentration of DL-aspartic acid was the optimum for maximal lipase production by Fusarium solani, while 1.5% was the optimum concentration for lipase production by Aspergillus terreus, Penicillium funiculosum and Fusarium moniliforme. Addition of vitamins to the growth medium revealed that thiamine was the most suitable for A. Terreus and F. moniliforme, pyridoxine HCl for F. Solani, and riboflavin for P. funiculosum. Addition of trace elements to the growth medium indicated that copper inhibited lipase production by all isolates. On the other hand, low levels of iron, magnesium, potassium and zinc were stimulatory for lipase production, while the high levels were inhibitory. Study of the effect of growth hormones on lipase synthesis revealed that indole acetic acid [IA] or gibberellic acid [GA] caused a stimulatory effect, while abscisic acid [AA] was inhibitor for lipase production by the tested isolates

Proteolytic activity saccharomyces cerevisiae as affected by cultural conditions.1-Effect of certain environmental conditions

The protelytic activity of S. cerevisiae was studied under the influence of some environmental and cultural conditions. The optimum temperature necessary for maximum proteolytic activity was 30§, the optimum incubation period was 5 days, the optimum pH value was 5. Maximum biomass yield and proteolytic activity was given at 0.5 g/1 NaCl concentration. 5 g/1 of glucose gave maximum biomass yield, but the maximal proteolytic activity was attained in culture media free from sugar content. Effect of shaking was studied. The agitated cultures gave growth parameters and proteolytic activity much more than the static cultures

Proteolytic activity of saccharomyces cerevisiae as affected by cultural conditions. II. Effect of some nutritional requirements

Supplementation of the fermentation medium with different nitrogen and carbon sources and their effects on growth and proteinase production by S. cerevisiae was studied. Organic complex nitrogen compounds enhanced yeast growth and stimulated the process of proteinase production. Similarly, medium fortified with molasses produced the highest growth and proteinase yields. Effect of different concentrations of peptone as the best nitrogen source - on growth and proteinase production by the yeast cells was also studied. 0.5% was the optimum concentration of peptone at which maximum growth and proteinase production were yielded. Effect of different concentrations of molasses - as the best carbon source - was studied. 1.0% was the optimum concentration of molasses at which maximal biomass yield was gained. Increasing molasses concentration in the medium resulted in a concomitant decrease of the proteolytic activity of the organism

Bioconversion of corn straw by yeast into biomass protein under the influence of trace elements

Saccharomyces carlsbergensis has been cultivated on fermentation media consisting of corn straw hydrolysate [CSH] as a sole carbon and nitrogen source, and supplemented with different concentrations of either iron, zinc or boron. Growth features, especially protein production by the yeast have been studied. The presence of low and moderate concentrations of iron boron in the fermentation media raised the biomass gain and the protein content of the yeast cells, while high concentrations of these trace elements retarded both growth and protein synthesis. Zinc impaired both biomass yield and protein production by the tested organism. Boron was found to be a good stimulant, when added in a concentration of 10-5 M to corn straw hydrolysate. Addition of iron at a 10-4 M concentration to the fermentation media in a mixture with boron at a level of 10-6 M enhanced both growth and protein yield. Also, addition of boron at level 10-5 M in a mixture with iron at 10-5 M concentration to corn straw hydrolysate media stimulated both growth and protein yield. This constitutes a promising fermentation medium for protein production by yeast

Lipid production by yeast utilizing whey under the influence of microelements and vitamins

Candida utilis was allowed to grow on a fermentation medium containing whey as a substitute of carbon and N sources. This medium was supplemented with Fe, Zn, Mn and Cu as trace elements in different levels to determine the optimum concentration of each microelement which causes best growth of the yeast accompanied with higher amount of lipids accumulated within the cells. The optimum concentrations of the tested microelements were 10-4, 10-5, 10-5 and 10-6 M for Fe, Zn, Mn and Cu, respectively. The effect of the four tested vitamins [thiamine, riboflavin, folic acid and nicotinamide] on both growth and lipid production by the yeast was also studied. Addition of thiamine, riboflavin or nicotinamide to the whey-containing media at a level of 0.3 g/l produced a higher growth, while supplementation of the fermentation media with 0.4 g/l folic acid produced maximum growth