Degradation of monoaromatics by Bacillus pumilus MVSV3

ABSTRACT Monoaromatics, such as benzene, toluene, ethylbenzene and xylene (BTEX), are simple aromatic compound that are highly toxic due to their high solubility nature. Many chemical and physical methods for their degradation and breakup into nontoxic products are available, but still use of microorganism is preferred over these processes. In this present study Bacillus pumilus MVSV3 (Accession number JN089707), a less explored bacteria in the field of BTEX degradation, isolated from petroleum contaminated soil is utilized for BTEX degradation. At optimized conditions the isolate degraded 150 mg/L of BTEX completely within 48 h. GC-MS analysis revealed that the microorganism produces catechol and muconic acid during degradation indicating an ortho pathway of degradation. Enzyme assays were carried out to identify and characterize catechol 1, 2- dioxygenase (C12D). The optimal temperature and pH for the enzyme activity was identified as 35 (C and 7.5, respectively. SDS-PAGE revealed the molecular weight of the enzyme to be approximately 35,000 Da. Zymography analysis indicated the presence of three isoforms of the enzyme. Hence Bacillus pumilus MVSV3 and the isolated C12D, proved to be efficient in degrading the toxic aromatic compounds.

Copper removal from aqueous solution by marine green alga Ulva reticulata

The batch removal of copper (II) ions from aqueous solution under different experimental conditions using Ulva reticulata was investigated in this study. The copper (II) uptake was dependent on initial pH and initial copper concentration, with pH 5.5 being the optimum value. The equilibrium data were fitted using Langmuir and Freundlich isotherm model, with the maximum copper (II) uptake of 74.63 mg/g determined at a pH of 5.5. The Freundlich model regression resulted in high correlation coefficients and the model parameters were largely dependent on initial solution pH. At various initial copper (II) concentrations (250 to 1000 mg/L), sorption equilibrium was attained between 30 and 120 min. The copper (II) uptake by U. reticulata was best described by Pseudo-second order rate model and the rate constant, the initial sorption rate and the equilibrium sorption capacity were also reported. The elution efficiency for copper-desorption from U. reticulata was determined for 0.1 M HCl, H2SO4, HNO3 and CaCl2 at various Solid-to-Liquid ratios (S/L). The solution CaCl2 (0.1 M) in HCl at pH 3 was chosen to be the most suitable copper-desorbing agent. The biomass was also employed in three sorption-desorption cycles with 0.1 M CaCl2 (in HCl, pH 3) as the elutant.