A local isolate of Aspergillus terreus was selected among different microorganisms as a new cyclosporin A (Cy A) producing culture. The formation of Cy A was investigated under different fermentation conditions (including selection of the cultivation medium, fermentation time course, inoculum nature, medium volume, agitation rate, pH value). Relatively high Cy A productivities were maintained when the fermentation process was carried out using a medium composed of (g/L): glucose, 50; bactopeptone, 10; KH(2)PO(4), 5; KCl, 2.5; pH 5.3, inoculated with 2% standard inoculum of 48 h age, shaken at 200 rpm for 10 days.

The formation of cyclosporin A (Cy A) by immobilized spores and mycelia of Aspergillus terreus was investigated. Different carriers were tested as immobilizing carriers, whereby Ca-alginate was selected for further experimentation. The role of alginate concentration, biomass weight, pH value of the cultivation medium, repeated utilization of the immobilized fungus as well as the supplementation of different amino acid precursors were studied. Best Cy A outputs were attained with Ca-alginate 3% (w/v), mycelial weight 15% (w/v), pH 4.5 and four repeated cycles. Similarly, the Cy A productivity was markedly accelerated in the presence of L-valine and L-valine and L-leucine mixture.

Bacterial conversion of lactose to calcium lactobionate was carried out by twelve strains of bacteria. The strain Bacillus spp. E showed high lactose oxidizing activities, when cultivated at 30˚C for 7 days in a medium ( pH 6) containing (g/100ml): lactose ,5; KH 2 PO 4 ,0.06 ; MgSO 4 .7H 2 O, 0.025; corn steep liquor ,0.75 ml ; 1 drop of soybean oil ; 1.5ml of 20% urea solution and CaCO 3 ,2.5 added during inoculation. The oxidizing activity was the highest where a relatively high lactose conversion (82%) was obtained at a lactose concentration of 50g/l . The activity remained almost stable between pH 5 and 6 and high conversion efficiency ( about 90%) was achieved at pH 0.6.