Quantitative and qualitative studies on bacterial microflora of fish reared in brackish water fish farm in Alexandria

A population of heterotrophic bacteria from a brackish water fish farm was estimated using a spread plate technique. Bacterial population in winter was relatively low compared with counts in summer when the maximum water temperature and organic matter content were recorded. Tilapia and mugil spp reared in the farm were bacteriologically sampled to determine the numbers of heterotrophs associated with the skin, gills and intestinal tract of the fish. The bacterial populations associated with different parts of fish consisted of diverse array of taxa; mainly, Pseudomonas, Vibrio, Aeromonas and Flavobacterium. There was a correlation between bacteria and type of reared fish

Isolation and immobilization of dextransucrase from leuconostoc mesenteroides cultures

The time course of dextransucrase production by immobilized cells of Leuconostoc mesenteroides DSMZ 20241 in calcium alginate beads, the concentration of alginate gel, the size of bead inoculum and the successive reuse of beads were studied. Isolation and partial purification of the crude dextransucrase were carried out by fractional precipitation with acetone or ammonium sulfate separately. The fraction obtained at 75% ammonium sulfate saturation was most active. Further purification was conducted by gel filtration on sephadex G-100 and the most active protein peak was rechromatographed on CM-sephadex C-50. Immobilization of the purified enzyme on various supports was carried out. The enzyme had a relatively low thermostability, but the immobilized enzyme was more resistant to different heat treatments than the free enzyme. Some ions as Zn+2 and lead partially inhibited the activities of different purified dextransucrase preparations, while other ions as Ca+2 and Fe+3 enhanced their activities

Coliforms as a measure of sewage pollution of Alexandria coastal water

The pollution of the coastal water of Alexandria, Egypt, was studied through one year period. Samples were collected monthly from four selected regions. Coliforms [fecal and nonfecal], as a measure of sewage contamination, were isolated and counted. Physical and chemical parameters of the water samples [temperature, pH, alkalinity, salinity, dissolved oxygen, organic matter, phosphate, nitrite, nitrate, ammonia, as well as calcium and magnesium] were determined and the interrelations between these parameters and coliform counts were also elucidated using statistical analyses