M. Altaf Khan

BIODEGRADATION OF CYPERMETHRIN BY PSEUDOMONAS IN A BATCH ACTIVATED SLUDGE PROCESS

The biodegradation of Cypermethrin (20 to 125 mg/L) in an effluent using batch activated sludge was studied. Degradation was found to occur to a great extent only in the presence of Pseudomonas (IES-Ps-1) culture. Under aerobic conditions using mechanical aerators, Cypermethrin (20 mg/L) was almost completely degraded in just over 48 h at ambient temperature. Further loading of organic compound in subsequent experiments demonstrated that IES-PS-1was capable to degrade 82 % Cypermethrin at 40 mg/L dose in approximately 48 h. When the concentration was increased to 80 mg/L, 50% degradation of this compound was observed. Over this time period the cells could utilize only 17 % of Cypermethrin when it was given 125 mg/L, respectively. These findings indicate that increased concentration of Cypermethrin has a marked effect on biodegradation performance of IES-Ps-1 with a modest increased in the duration of lag phase, but did not lead to complete inhibition or cell death. These results proved that IES-Ps-1 is responsible for Cypermethrin degradation. Such finding may be useful in designing a scale-up in situ or on-site hazardous waste bioremediation process for field application.

Studies on the recovery of sludge protein

Abstract The effect of sodium hydroxide and sodium chloride alone as well as in combination on sludge protein solubilization was investigated. Sodium hydroxide treatment was found superior as a maximum protein solubilization (90%) was obtained by its use at pH 12.5. For the extraction of protein hydrochloric acid, sodium lignosulphonate, sulphuric acid, acetic acid and ammonium sulphate, as protein precipitating agents, were also tried. Of all the precipitants used ammonium sulphate (40%) was found most effective giving a maximum protein recovery (91%). Four parameters were mainly studied for the characterization of recovered protein. These include determination of total protein, moisture, ash and heavy metals. It was also found that protein recovery unit processes removed most of the metals originally present in the primary sludge and the recovered product contained all the essential amino acids which could serve as an animal feed supplement.

Amino acid requirement of six strains of Listeria monocytogenes

Different serovars of Listeria monocytogenes grew well in a chemically defined medium. Sixteen amino acids were tested for the growth of L. monocytogenes. Most strains required cystine, valine, isoleucine, and leucine. Phenylalanine was a stimulatory growth factor for all six strains of Listeria. Whilst tryptophan was essentially required by NCTC 7973, LM and C-286 and stimulatory for 4155 and C-294, none of the strains did exhibit requirements of asparagine, glutamine, proline, histidine and tyrosine as essential/stimulatory growth factor.

Correlation between production of Listeriolysin O by variants of Listeria monocytogenes and their virulence for rabbits

L. monocytogenes serovar 1/2a NCTC 7973 was passaged through rabbits and the severity of infection at each passage was determined by counting viable bacteria from infested organs and recording the time of death. A comparative evaluation of the levels of hemolysin produced in vitro by the original and six variant cultures (V1-V6) was done by determination of hemolytic units (CHU). While virulence of the cultures enhanced at each passage (2.2 x 10(9) CFU/g of the spleen for V6 as compared to 5.0 x 10(6) CFU/g spleen for the parent culture), the CHU decreased considerably, 3 CHU for the V6 as compared to 40 CHU for the parent strain. The results suggest that the level of in vitro production of listeriolysin may not parallel the pathogenicity of L. monocytogenes for rabbits.

An Application of Principal Component Analysis to The Study of Activated Sludge Treatment System Performance Efficiency For the Degradation of Malathion

The biosimulator system (activated sludge system) have proved to be very effective in the treatment of wastewater containing high content of pesticide and Chemical Oxygen Demand (COD) in terms of organic load and the quality of effluent being obtained after treatment was acceptable for landscape irrigation and for growing plants of ornamental value for commercial use. The biosimulator can be operated without being an aesthetic nuisance at a considerably low Dissolved Oxygen (DO). The efficiency of the biosimulator at high organic load (pesticide inobulated) and the inoculation of strain of Pseudomonas capable of degrading malathion, could be used to minimize time for treating wastewater containing high content of hazardous pesticide.The principal component analysis exposed the groups of correlated variables and their importance in the data structure. MalIN -MalOUT, TMC, MalOUT/MalIN and CODOUT/CODIN were highly correlated with each other and emerged as the variables controlling the first component. DO, pH and retention time governed the second component. The third component of PCA essentially repeated the trend exhibited by the first two components. The presence of pesticides or their metabolites, emphasizes the need for conducting monitoring studies, in order to draw a national picture for overall assessment of the situation.