Optimization of garden radish [raphanus sativus l.] peroxidase enzyme for removal of 2,4-dichlorophenol from 2,4- dichlorophenoxyacetic acid wastewater

Environmental pollution by 2,4-dicholorphenol [2,4-DCP], commonly found in industrial wastewater has been a concern for humans over the past 50 years. Garden Radish Peroxidase [GRP] can eliminate this poisonous pollutant. The aim of this study was to apply an experimental Response Surface Methodology [RSM] and Central Composite Design [CCD] to optimize GRP-based treatment in order to maximize the removal of 2,4-DCP from wastewater. The effects of four factors; pH, enzyme activity [U/mL], hydrogen peroxide [H[2]O[2]] concentration [mM], and substrate concentration [mg/L] and their interactions were investigated for 2,4-DCP removal using a second-order polynomial model. The suitability of the polynomial model was described using coefficient of determination [R[2] =90.7%] and the results were created by analysis of variance [ANOVA]. A 3D response surface was made from the mathematical models and then applied to determine the optimal condition. These analyses exhibited that using a quadratic model was fitting for this treatment. Furthermore, desirability function was employed for the specific values of controlled factors for optimization and maximum desirability. Based on the desirability function results, the response predicted a 99.83% removal rate of 2,4-DCP from wastewater with 0.959 desirability. Under these conditions, the experimental removal percentage value would be 99.2%

Dietary overlap between invasion ctenophora [M . leidyi ] and anchovy [C. engrauliformis] in the southern parts of Caspian Sea

Mnemiopsis leidyi, native to America, Invaded the Caspian Sea in 1999. By the end of 2000, the entire sea was accupied with them. In parallel, a sharp decline in pelagic fish such accurrred. This survey was studied the relationship between the M. leidyi and this decline. Dietary analysis was conducted on anchovy sprat [Clupeonnela engrauliformis] and M. leidyi from August 2001 to October 2002 in the coastal water in the southern parts of Caspian Sea, in Iran. M. leidyi was caught by plankton net, [the mesh size -5 mm], at three depth at 5, 10 and 15 m. Sprat was caught by fisheries boat at Babolasar fishery harbor. Samples were not fixed in M. leidyi common fixative, 96% Ethanol were used. The Schoener index analysis reflected a similar diet composition of both species, with an critical level of overlap [>89 in Babolsar samples and >84 in Noushahar samples]. This competition is one of the reasons for the decline of anchovy sprat. also, the results show M. leidyi is feeding on fish eggs, but effects of this factor on anchovy population is less than feeding competition. Controlling of M. leidyi population is reducing the pressure of its invasion and the effective approach is introduces a predator to the Caspian Sea