Optimization of different cultural conditions for m-cresol degradation by free and immobilized bacillus laterosporus cells

Optimization of the cultural conditions that facilitate the degradation of m-cresol by a locally isolated bacterial strain Bacillus laterosporus free and entrapped cells was attempted. Bacterial cells entrapped in 2% Ca-allginate beads were more active than free cells and showed a 20% higher rate of m-cresol degradation. Medium No. 1 was most favorable for m-cresol utilization. Supplementing the medium with yeast extract stimulated degradation especially at concentration 0.2 g/l. Optimum concentration of ammonium salts, phosphate salts and magnesium sulfate were 3 g/l and 1.5 g/l, respectively. Optimum concentration of trace elements was 4 ml/l and its omission reduced the rate of degradation. Initial pH of the medium that gave the highest rate of degradation was pH 7 and incubation temperature of 35C. Addition of some amino acids to the mineral medium did not improve degradation rate. The best alginate concentration was 2% and the optimum quantity of beads was 20 ml/ 100 ml medium. The rate of degradation increased by increasing the m- cresol concentration up to 500 mg/l, while higher concentrations [1 g/l] decreased the degradation ability of the entrapped cells

Degradation of meta-cresol in waste waters by entrapped bacillus laterosporus cells

Degradation of m-cresol in different waste water samples instead of the mineral medium was carried out. Meta-cresol degradation in nonsterile waste water was slower than in sterile. However, the entrapped Bacillus laterosporus cells proved to actively degrade m- cresol in all the tested water samples except in the case of two samples collected from El-Max region near Alexandria Harbor. The growth and rate of degradation in both free and entrapped cell cultures were affected by Pb and Hg salts at concentrations higher than 10 mg/l. The rate of degradation was reduced by 75% when 100 mg/l and salts of these metals were present in the medium. Also, the rate of degradation was reduced in presence of 5 mg/l of zinc or cadmium salts. It was noticed that entrapped cells did not show higher resistance than the free cells in presence of the tested heavy metals. The presence of 4-chlorophenol, 4-bromophenol or p- nitrophenol in the medium delayed the degradation time and the rate of degradation was much lower in presence of these substituted phenols together with m-cresol. However, the degradation activity was not completely lost

Environmental studies of seawater along the Egyptian mediterranean beaches between Port-Said and Gamasa

Monthly sea water samples were collected from the beaches of Gamasa. Ras El-Bar [Damietta estuary] and port said during the period from July, 1992 to June, 1993. The environmental parameters, salinity, dissolved oxygen, nitrate, nitrite, ammonia, urea, phosphate and silicate were measured. The results reveal that, generally, port-said region exhibited higher leveles of nutrient salts with respect to those in the other areas mainly due to the outflowing of breackish water enriched with these nutrients from lake manzala. Also damietta branch has little effect on the sea as its Nile water has been efficiently damned in the branch 20 km landward by faraskour dam

Distribution of some heavy metals in coastal recreational areas off Port-Said

During the period from July 1992 to June 1993 samples were taken from 7 areas at port-said coast. The distribution of dissolved and particulate [Seston] heavy metals are reported with their relationships to salinity. The concentration of dissolved heavy metals ranged between 0.15-0.68 ppb, 0.15-2.90 ppb, 0.38-1.99 ppb and 0.62-7.62 ppb for Cd, Cu, pb and zn respectively in the same respect, these values for particulate forms [seston] were 0.00-0.25 ppb, 0.08-0.92 ppb, 0.10-1.52 ppb and 1.16-9.92 ppb. In areas of high salinity, higher concentrations of dissolved Cd and Cu were found to be not affected with local inputs, but the situation with respect to lead and zinc were found to be more complicated. The opposite was found for particulate Cd and Cu. At lower salinities, higher or lower Cd, Cu, pb and Zn concentrations were found to be associated with local inputs