Recent developments in l-glutaminase production and applications - An overview

l-glutaminases is an important industrial enzyme which finds potential applications in different sectors ranging from therapeutic to food industry. It is widely distributed in bacteria, actinomycetes, yeast and fungi. l-Glutaminases are mostly produced by Bacillus and Pseudomonas sp. and few reports were available with fungal, actinomycete and yeast system. Modern biotechnological tools help in the improved production as well as with tailor made properties for specific applications. Most of the genetic engineering studies were carried out for the production of l-glutaminase with improved thermo-tolerance and salt tolerance. Considering the potential of in vitro applications of l-glutaminase, extracellular enzymes are important and most microbes produce this enzyme intracellularly. Several research and developmental activities are going on for the extracellular production of l-glutaminase. This review discusses recent trends and developments and applications of l-glutaminases.

Synthesis of three dimensional nickel cobalt oxide nanoneedles on nickel foam, their characterization and glucose sensing application

In the present work, NiCo2O4 nanostructures are fabricated in three dimensions (3D) on nickel foam by the hydrothermal method. The nanomaterial was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The nanostructures exhibit nanoneedle-like morphology grown in 3D with good crystalline quality. The nanomaterial is composed of nickel, cobalt and oxygen atoms. By using the favorable porosity of the nanomaterial and the substrate itself, a sensitive glucose sensor is proposed by immobilizing glucose oxidase. The presented glucose sensor has shown linear response over a wide range of glucose concentrations from 0.005 mM to 15 mM with a sensitivity of 91.34 mV/decade and a fast response time of less than 10 s. The NiCo2O4 nanostructures-based glucose sensor has shown excellent reproducibility, repeatability and stability. The sensor showed negligible response to the normal concentrations of common interferents with glucose sensing, including uric acid, dopamine and ascorbic acid. All these favorable advantages of the fabricated glucose sensor suggest that it may have high potential for the determination of glucose in biological samples, food and other related areas.

Immobilization of glutaminase enzyme from Hypocria jecorina on polyacrylic acid: preparation and biochemical characterization

L-glutaminase enzyme produced from Hypocrea jecorina pure culture and polyacrylic acid (PAA) in the presence (Cu2+) ions were composed the ternary complex at pH 7. The properties of free and immobilized enzyme were defined. The effect of various factors such as pH, temperature, heat, and storage stability on immobilized enzyme were investigated. The properties of immobilized enzyme were investigated and compared to those of free enzyme. Optimum pH and temperature of both enzyme were determined to be 8.0 and 50°C, respectively. Kinetic parameters of the immobilized enzyme (Km and Vmax values) were also determined as 0.38 mM of the Km and 10.9 U/L of the Vmax. No drastic change was observed in the Km and Vmax values. Thermal and storage stability experiments were carried out. The thermal stability studies indicated that the immobilization process tends to stabilize the enzyme.