Evidence on the presence of two distinct alkaline phosphatases in Serratia marcescens

Certain strains of Serratia marcescens synthesized two different types of alkaline phosphatase (APase), constitutive (CAPase) and inducible (IAPase) APases, in low phosphate medium. Synthesis of the IAPase was repressed in the presence of high phosphate. Purification and separation of these electrophoretically distinct APases was achieved by using fractional (NH(4))(2)SO(4) precipitation, adsorption on a DEAE-cellulose column and elution of enzymes by a linear sodium chloride gradient. Starch gel electrophoresis of certain fractions revealed the separation of not only IAPase from CAPase but its separation into four distinct isozymes. CAPase gave maximum enzyme activity around pH 9.5, whereas for IAPase a broad range of enzyme activity was found between pH 8.5 and 10.5. Reversible inactivation at low pH occurred for IAPase but very little with CAPase. CAPase was more thermolabile than IAPase at 95 degrees C. The two APases were found to be distinct in their kinetic as well as immunological properties, suggesting two distinct enzyme species.     

Optimal Testing for Serial Correlation in a Large Number of Small Samples

In recent years, there has been an increased awareness of the potential one-sided nature of many testing problems in applied sciences. Usually, these testing problems can be reduced, either by conditioning on sufficient statistics or by invariant techniques. COX and SOLOMON (1988) considered testing the serial correlation coefficient of a stationary first order autoregressive process and concentrated on four independent samples, with each of size three. We outline a general method for testing the serial correlation coefficient, using locally best invariant, point optimal invariant and locally most mean powerful invariant test procedures. The first procedure optimizes power near the null hypothesis, the second optimizes it at a pre-determined point away from the null while the third optimizes the average curvature of the power hypersurface in the neighbourhood of the null hypothesis.     

Column bioleaching of low-grade mining ore containing high level of smithsonite,talc, sphaerocobaltite and azurite

Present work describes the bioleaching potential of metals from low-grade mining ore containing smithsonite, sphaerocobaltite, azurite and talc as main gangue minerals with adapted consortium of Sulfobacillus thermosulfidooxidans strain-RDB and Thermoplasma acidophilum. Bioleaching potential improved markedly by added energy source, acid preleaching and adaptation of microbial consortium with mixed metal ions. During whole leaching period including acid preleaching stage of 960 h and bioleaching stage of 212 days about 76% Co, 70% Zn, 84% Cu, 72% Ni and 63% Fe leached out.     

Removal and recovery of Cu(II) and Zn(II) using immobilized Mentha arvensis distillation waste biomass

The potential use of the immobilized Mentha arvensis distillation waste (IMADW) biomass for removal and recovery of Cu(II) and Zn(II) from aqueous was evaluated in the present study. Biosorption capacity of Cu(II) and Zn(II) on IMADW increased with increase in pH reaching a maximum at 5 for Cu(II) and 6 for Zn(II). The equilibrium sorption data agreed well with Langmuir isotherm model and pseudo-second-order kinetic model in batch mode. Cu(II) and Zn(II) uptake by IMADW was best described by pseudo-first-order kinetic model in continuous mode. Maximum Cu(II) and Zn(II) uptake by IMADW was 104.48 and 107.75 mg/g, respectively. Fourier Transform Infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were also carried out to investigate functional groups and surface changes of biomass. The results showed that IMADW biomass is a potential biomaterial to remove Cu(II) and Zn(II) ions with a high biosorption capacity from aqueous solutions.