Kinetics and mechanism of interaction of hexaaquachromium(III) with <Emphasis Type="SmallCaps">l</Emphasis>-Dopa in aqueous medium: comparative antiparkinsonian studies

The kinetics and mechanism of the substitution reaction between [Cr(H₂O)₆]³⁺ and l-Dopa in aqueous medium has been studied over the range 1.8 ≤ pH ≤ 2.6, 1.68 × 10⁻² mol dm⁻³ ≤ [Dopa] ≤ 5.04 × 10⁻² mol dm⁻³, I = 0.1 mol dm⁻³ (KNO₃) at 50 °C. The reaction takes place via an outer sphere association between Cr³⁺ and l-Dopa followed by chelation. The product was characterized by physicochemical and infrared spectroscopic methods. The antiparkinsonian activity of the product was found to be higher than that of l-Dopa.     

The Comparison of Lutein Production by <Emphasis Type="Italic">Scenesdesmus</Emphasis> sp. in the Autotrophic and the Mixotrophic Cultivation

The results of this study indicate that an increase in CO₂ percentage to 30% can enhance Scenedesmus sp. growth in autotrophic cultivation to a maximum of 0.85 g/l as compared with 0.6 g/l obtained in the batch with air (after 6 days of cultivation). However, while the CO₂ was higher than 30%, it showed a negative impact on cell growth. A mixotrophic cultivation with 3 g/l of glycerol can achieve 0.38 g l⁻¹ day⁻¹ of the maximum biomass productivity compared with that of 0.21 g l⁻¹ day⁻¹ in autotrophic cultivation. Nevertheless, the lutein content of the mixotrophic cultivation was 0.08–0.1% lower than 0.2–0.25% obtained in autotrophic cultivation, which led to a lower lutein productivity of 0.36 mg l⁻¹ day⁻¹ in the mixotrophic batch compared with 0.44 mg l⁻¹ day⁻¹ obtained in the autotrophic batch. The limitation of cell growth in the mixotrophic cultivation would be the contributing factor regarding the lower lutein productivity. The mixotrophic cultivation of repeated batch to remove potential inhibitive metabolic products from glycerol catabolism does not show an obvious improvement on biomass. Conclusively, mixotrophic cultivation achieves higher biomass productivity with lower lutein content than that of autotrophic cultivation, which leads to lower lutein productivity. Therefore, the autotrophic cultivation is preferred in the lutein production.     

Bioconversion of Sodium Dodecyl Sulphate to Rhamnolipid by Pseudomonas aeruginosa: A Novel and Cost-Effective Production Strategy

The utility of rhamnolipids in industry is currently limited due to the high constraints in its economic production. In this scenario, the novel utility of sodium dodecyl sulphate (SDS) as carbon source could serve as promising cost-effective strategy. Screening of effective SDS biodegraders led to the isolation of Pseudomonas aeruginosa S15 capable of concomitant SDS degradation and biosurfactant synthesis. SDS-based rhamnolipid production was proved on SDS minimal agar plates using cetyl trimethylammonium bromide–methylene blue method and optimised in SDS-based minimal salt (SBS) medium. SDS proved to be an ideal carbon source for rhamnolipid synthesis with a high substrate to product conversion rate yielding 6.9 g/l of rhamnolipids from 1 g/l SDS in 5 days. Fast atom bombardment mass spectroscopy analysis of the purified biosurfactant proved the presence of mono- and di-rhamnolipids, viz., Rha-C₁₀-C₁₀, Rha-C₁₀-C₁₂ and Rha-Rha-C₁₀-C₁₀ with surface active properties. The secreted rhamnolipids were not utilised by S15 as a carbon source, but it caused a dispersion of bacterial biofilms in SBS medium. To the best of our knowledge, this is the first report on bioconversion of synthetic detergent to biodetergent. This SDS-based novel methodology presents a more economised mode of rhamnolipid synthesis utilising SDS as sole carbon source.     

Thermal properties of amphiphilic biodegradable triblock copolymer of <Emphasis Type="SmallCaps">l</Emphasis>,<Emphasis Type="SmallCaps">l</Emphasis>-lactide and ethylene glycol

Samples of poly(l,l-lactide)-block-poly(ethylene glycol)-block-poly(l,l-lactide) (PLLA-PEG-PLLA) were synthesized from l,l-lactide polymerization using stannous 2-ethylhexanoate, Sn(Oct)₂ as initiator and di-hydroxy-terminated poly(ethylene glycol) (PEG) (M _n  = 4000 g mol⁻¹) as co-initiator. The chemical linkage between the PEG segment and the PLA segments was characterized by Fourier transform infrared spectroscopy (FTIR). Thermogravimetry analysis (TG) revealed the copolymers composition and was capable to show the deleterious effect of an excess of Sn(Oct)₂ in the polymer thermal stability, while Differential Scanning Calorimetry (DSC) allowed the observation of the miscibility between the PLLA and PEG segments in the different copolymers.     

Solid state electrochemical of the erbium hexacyanoferrate-modified carbon ceramic electrode and its electrocatalytic oxidation of <Emphasis Type="SmallCaps">l</Emphasis>-cysteine

A kind of erbium hexacyanoferrate (ErHCF)-modified carbon ceramic electrodes (CCEs) fabricated by mechanically attaching ErHCF samples to the surface of CCEs derived from sol–gel technique was proposed. The resulting modified electrodes exhibit well-defined redox responses with the formal potential of +0.215 V [vs saturated calomel electrode (SCE)] at a scan rate of 20 mV s⁻¹ in 0.5 M KCl (pH 7) solution. The voltammetric characteristics of the ErHCF-modified CCEs were investigated by voltammetry. Attractively, the ErHCF-modified CCEs presented good electrocatalytic activity with a marked decrease in the overvoltage about 400 mV for l-cysteine oxidation. The calibration plot for l-cysteine determination was linear at 5.0 × 10⁻⁶–1.3 × 10⁻⁴ M with a linear regression equation of I(A) = 0.558 + 0.148c (μM) (R ² = 0.9989, n = 20), and the detection limit was 2 × 10⁻⁶ M (S/N = 3). At last, the ErHCF-modified CCEs were used for amperometric detection of l-cysteine in real samples.     

Production of biosurfactant from a new and promising strain of Pseudomonas aeruginosa PA1

The Pseudomonas aeruginosa PA1 strain, isolated from the water of oil production in Sergipe, Northeast Brazil, wasevaluated as a potential rhamnolipid type of biosurfactant producer. The production of biosurfactants was investigated using different carbon sources (n-hexadecane, paraffin oil, glycerol, and babassu oil) and inoculum concentrations (0.0016–0.008 g/L) The best results were obtained with glycerol as the substrate and an initial cell concentration of 0.004 g/L. AC:N ratio of 22.8 led to the greatest production of rhamnolipids (1700 mg/L) and efficiency (1.18 g of rhamnolipid/g of dry wt).     

Mechanistic studies on the intramolecular electron transfer in an adduct species of the oxo-centred trinuclear iron(III) cation and <Emphasis Type="SmallCaps">l</Emphasis>-ascorbic acid in aqueous solution

The kinetics of the intra-molecular electron transfer of an adduct of l-ascorbic acid and the [Fe₃^IIIO(CH₃COO)₆(H₂O)₃]⁺ cation in aqueous acetate buffer was studied spectrophotometrically, over the ranges 2.55 ≤ pH ≤ 3.74, 20.0 ≤ θ ≤ 35.0 °C, at an ionic strength of 0.50 and 1.0 mol dm⁻³ (NaClO₄). The reaction of l-ascorbic acid and the complex cation involves the rapid formation of an adduct species followed by a slower reduction in the iron centres through consecutive one-electron transfer processes. The final product of the reaction is aqueous iron(II) in acetate buffer. The proposed mechanism involves the triaqua and diaqua-hydroxo species of the complex cation, both of which form adducts with l-ascorbic acid. At 25 °C, the equilibrium constant for the adduct formation was found to be 86 ± 15 and 5.8 ± 0.2 dm³ mol⁻¹ for the triaqua and diaqua-hydroxo species, respectively. The kinetic parameters derived from the rate expression have been found to be: k ₀ = (1.12 ± 0.02) × 10⁻² s⁻¹ for the combined spontaneous decomposition and k ₁ = (4.47 ± 0.06) × 10⁻² s⁻¹ (ΔH ₁^‡ = 51.0 ± 2.3 kJ mol⁻¹, ΔS ₁^‡ = −100 ± 8 J K⁻¹ mol⁻¹), k ₂ = (4.79 ± 0.38) × 10⁻¹ s⁻¹ (ΔH ₂^‡ = 76.5 ± 0.8 kJ mol⁻¹, ΔS ₂^‡ = 6 ± 3 J K⁻¹ mol⁻¹) for the triaqua and diaqua-hydoxo species, respectively.     

A kinetic study of the oxidation of <Emphasis Type="SmallCaps">l</Emphasis>-methionine by water soluble colloidal MnO<Subscript>2</Subscript>

Aqueous solution of water soluble colloidal MnO₂ was prepared by Perez-Benito method. Kinetics of l-methionine oxidation by colloidal MnO₂ in perchloric acid (0.93 × 10⁻⁴ to 3.72 × 10⁻⁴ mol dm⁻³) has been studied spectrophotometrically. The reaction follows first-order kinetics with respect to [H⁺]. The first-order kinetics with respect to l-methionine at low concentration shifts to zero order at higher concentration. The effects of [Mn(II)] and [F⁻] on the reaction rate were also determined. Manganese (II) has sigmoidal effect on the rate reaction and act as auto catalyst. The exact dependence on [Mn(II)] cannot be explained due to its oxidation by colloidal MnO₂. Methionine sulfoxide was formed as the oxidation product of l-methionine. Ammonia and carbon dioxide have not been identified as the reaction products. The mechanism with the observed kinetics has been proposed and discussed.     

Production of Lipid and Fatty Acids during Growth of <Emphasis Type="Italic">Aspergillus terreus</Emphasis> on Hydrocarbon Substrates

An Aspergillus terreus, isolated from oil contaminated soil, could degrade a wide range of petroleum hydrocarbons including the immediate oxidation products of hydrocarbons, like alkanols and alkanals. Among all the linear chain carbon substrates, highest growth of 39.1 ± 3.8 g l⁻¹ (wet weight) was observed when n-hexadecane was used as the sole source of carbon. The growth of the fungus on this highly hydrophobic substrate was associated with the morphological change of the hyphae and increase production of lipid in the cells. The lipid production in the hydrocarbon (n-hexadecane) grown cells was sevenfold higher than the corresponding glucose grown cells. The fatty acid profile of the lipid content formed in the hydrocarbon grown cells was significantly different from the glucose grown cells and was composed of fatty acids with chain length C₁₄ to C₃₃ as revealed from the liquid chromatography electrospray ionization mass spectrometry analyses. Among the ranges, the fatty acids with chain lengths C₁₄ to C₁₈ were predominant in the profile. Considering the fatty acid profile and the high level of lipid production, this A. terreus mediated production of lipid is envisaged to have potential application in the oleochemical industries including the production of biodiesel.     

Scale up and Application of Biosurfactant from <Emphasis Type="Italic">Bacillus subtilis</Emphasis> in Enhanced Oil Recovery

There is a lack of fundamental knowledge about the scale up of biosurfactant production. In order to develop suitable technology of commercialization, carrying out tests in shake flasks and bioreactors was essential. A reactor with integrated foam collector was designed for biosurfactant production using Bacillus subtilis isolated from agricultural soil. The yield of biosurfactant on biomass (Y _p/x), biosurfactant on sucrose (Y _p/s), and the volumetric production rate (Y) for shake flask were obtained about 0.45 g g⁻¹, 0.18 g g⁻¹, and 0.03 g l⁻¹ h⁻¹, respectively. The best condition for bioreactor was 300 rpm and 1.5 vvm, giving Y _x/s, Y _p/x, Y _p/s, and Y of 0.42 g g⁻¹, 0.595 g g⁻¹, 0.25 g g⁻¹, and 0.057 g l⁻¹ h⁻¹, respectively. The biosurfactant maximum production, 2.5 g l⁻¹, was reached in 44 h of growth, which was 28% better than the shake flask. The obtained volumetric oxygen transfer coefficient (K _L a) values at optimum conditions in the shake flask and the bioreactor were found to be around 0.01 and 0.0117 s⁻¹, respectively. Comparison of K _L a values at optimum conditions shows that biosurfactant production scaling up from shake flask to bioreactor can be done with K _L a as scale up criterion very accurately. Nearly 8% of original oil in place was recovered using this biosurfactant after water flooding in the sand pack.     

Structure and Applications of a Rhamnolipid Surfactant Produced in Soybean Oil Waste

Soybean oil soapstock was utilized as an alternative carbon source for the production of rhamnolipids by Pseudomonas aeruginosa LBI strain. The chemical composition and properties of the rhamnolipid mixture obtained were determined to define its potential applications. The chemical characterization of the rhamnolipid has revealed the presence of ten different homologues. The monorhamnolipid RhaC₁₀C₁₀ and the dirhamnolipid Rha₂C₁₀C₁₀ were the main components of the mixture that showed predominance of 44% and 29%, respectively, after 144-h of cultivation. The biosurfactant was able to form stable emulsions with several hydrocarbons and showed excellent emulsification for soybean oil and chicken fat (100%). The rhamnolipid removed 67% of crude oil present in sand samples and presented antimicrobial activity against Bacillus cereus and Mucor miehei at 64 μg/mL and inhibition of Neurospora crassa, Staphylococcus aureus, and Micrococcus luteus at 256 μg/mL. The results demonstrated that the rhamnolipid produced in soybean oil soapstock can be useful in environmental and food industry applications.     

Mechanistic investigations on the oxidation of <Emphasis Type="SmallCaps">l</Emphasis>-valine by diperiodatocuprate(III) in aqueous alkaline medium: a kinetic model

The oxidation of l-valine (l-val) by diperiodatocuprate(III) (DPC) in aqueous alkaline medium at a constant ionic strength of 3.0 × 10⁻³ mol dm⁻³ was studied spectrophotometrically at 298 K and follows the rate law;

Plantlet Regeneration from Callus Cultures of Selected Genotype of <Emphasis Type="Italic">Aloe vera</Emphasis> L.—An Ancient Plant for Modern Herbal Industries

Aloe vera L., a member of Liliaceae, is a medicinal plant and has a number of curative properties. We describe here the development of tissue culture method for high-frequency plantlet regeneration from inflorescence axis-derived callus cultures of sweet aloe genotype. Competent callus cultures were established on 0.8% agar-gelled Murashige and Skoog’s (MS) basal medium supplemented with 6.0 mg l⁻¹ of 2,4-dichlorophenoxyacetic acid (2,4-D) and 100.0 mg l⁻¹ of activated charcoal and additives (100 mg l⁻¹ of ascorbic acid, 50.0 mg l⁻¹ each of citric acid and polyvinylpyrrolidone, and 25.0 mg l⁻¹ each of l-arginine and adenine sulfate). The callus cultures were cultured on MS medium containing 1.5 mg l⁻¹ of 2,4-D, 0.25 mg l⁻¹ of Kinetin (Kin), and additives with 4% carbohydrate source for multiplication and long-term maintenance of regenerative callus cultures. Callus cultures organized, differentiated, and produced globular embryogenic structures on MS medium with 1.0 mg l⁻¹ of 2,4-D, 0.25 mg l⁻¹ of Kin, and additives (50.0 mg l⁻¹ of ascorbic acid and 25.0 mg l⁻¹ each of citric acid, l-arginine, and adenine sulfate). These globular structures subsequently produced shoot buds and then complete plantlets on MS medium containing 1.0 mg l⁻¹ of 6-benzylaminopurine and additives. A hundred percent regenerated plantlets were hardened in the greenhouse and stored under an agro-net house/nursery. The regeneration system defined could be a useful tool not only for mass-scale propagation of selected genotype of A. vera, but also for genetic improvement of plant species through genetic transformation.     

Analysis of Carbon Metabolism and Improvement of γ-Polyglutamic Acid Production from <Emphasis Type="Italic">Bacillus subtilis</Emphasis> NX-2

Bacillus subtilis NX-2 produces γ-polyglutamic acid (γ-PGA) when using glucose and l-glutamate as carbon sources. The conversion of carbon sources into γ-PGA was analyzed with the ¹³C-NMR method after enriching the media with ¹³C-labeled glucose. The results showed that the percentage of γ-PGA monomers derived from glucose was relatively low, approximately 6% and 9%, respectively, with an initial glucose concentration of 30 and 40 g L⁻¹. It was concluded that glucose was utilized mainly as the growth-limiting substrate for cell growth and supplied the required energy during γ-PGA biosynthesis, while l-glutamate was preferred as the main substrate for γ-PGA formation. To achieve an efficient conversion of l-glutamate and enhance the γ-PGA production, a fed-batch culture was proposed by feeding of glucose. By this method, supplied l-glutamate (40 g L⁻¹) was completely depleted, and γ-PGA yield was attained 42 g L⁻¹.     

Characterization of a Thermostable Family 1 Glycosyl Hydrolase Enzyme from <Emphasis Type="Italic">Putranjiva roxburghii</Emphasis> Seeds

A 66-kDa thermostable family 1 Glycosyl Hydrolase (GH1) enzyme with β-glucosidase and β-galactosidase activities was purified to homogeneity from the seeds of Putranjiva roxburghii belonging to Euphorbiaceae family. N-terminal and partial internal amino acid sequences showed significant resemblance to plant GH1 enzymes. Kinetic studies showed that enzyme hydrolyzed p-nitrophenyl β-d-glucopyranoside (pNP-Glc) with higher efficiency (K _cat/K _m = 2.27 × 10⁴ M⁻¹ s⁻¹) as compared to p-nitrophenyl β-d-galactopyranoside (pNP-Gal; K _cat/K _m = 1.15 × 10⁴ M⁻¹ s⁻¹). The optimum pH for β-galactosidase activity was 4.8 and 4.4 in citrate phosphate and acetate buffers respectively, while for β-glucosidase it was 4.6 in both buffers. The activation energy was found to be 10.6 kcal/mol in the temperature range 30–65 °C. The enzyme showed maximum activity at 65 °C with half life of ~40 min and first-order rate constant of 0.0172 min⁻¹. Far-UV CD spectra of enzyme exhibited α, β pattern at room temperature at pH 8.0. This thermostable enzyme with dual specificity and higher catalytic efficiency can be utilized for different commercial applications.     

Production of Fumaric Acid by <Emphasis Type="BoldItalic">Rhizopus oryzae</Emphasis>: Role of Carbon–Nitrogen Ratio

Cytosolic fumarase, a key enzyme for the accumulation of fumaric acid in Rhizopus oryzae, catalyzes the dehydration of l-malic acid to fumaric acid. The effects of carbon–nitrogen ratio on the acid production and activity of cytosolic fumarase were investigated. Under nitrogen limitation stress, the cytosolic fumarase could keep high activity. With the urea concentration decreased from 2.0 to 0.1 g l⁻¹, the cytosolic fumarase activity increased by 300% and the production of fumaric acid increased from 14.4 to 40.3 g l⁻¹ and l-malic acid decreased from 2.1 to 0.3 g l⁻¹. Cytosolic fumarase could be inhibited by substrate analog 3-hydroxybutyric acid. With the addition of 3-hydroxybutyric acid (50 mM) in the fermentation culture, fumaric acid production decreased from 40.3 to 14.1 g l⁻¹ and l-malic acid increased from 0.3 to 5.4 g l⁻¹.     

Synthesis,Characterization, and Oil Recovery Application of Biosurfactant Produced by Indigenous <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> WJ-1 Using Waste Vegetable Oils

A bacterial strain was isolated and cultured from the oil excavation areas in tropical zone in northern China. The biochemical characteristics and partial sequenced 16S rRNA gene of isolate, WJ-1, was identical to those of cultured representatives of the species Pseudomonas aeruginosa. This bacterium was able to produce a type of biosurfactant. Compositional analysis revealed that the extracted biosurfactant was composed of high percentage lipid (∼74%, w/w) and carbohydrate (∼20%, w/w) in addition to a minor fraction of protein (∼6%, w/w). The best production of 50.2 g/l was obtained when the cells were grown on minimal salt medium containing 6.0% (w/v) glucose and 0.75% (w/v) sodium nitrate supplemented with 0.1% (v/v) element solution at 37 °C and 180 rpm after 96 h. The optimum biosurfactant production pH value was found to be 6.0–8.0. The biosurfactant of WJ-1, with the critical micelle concentration of 0.014 g/L, could reduce surface tension to 24.5 mN/m and emulsified kerosene up to EI₂₄ ≈95. The results obtained from time course study indicated that the surface tension reduction and emulsification potential was increased in the same way to cell growth. However, maximum biosurfactant production occurred and established in the stationary growth phase (after 90 h). Thin layer chromatography, Fourier transform infrared spectrum, and mass spectrum analysis indicate the extracted biosurfactant was affiliated with rhamnolipid. The core holder flooding experiments demonstrated that the oil recovery efficiency of strain and its biosurfactant was 23.02% residual oil.     

Design of silica microparticles with oligopeptide brushes and their interaction with proteins

Synthesis of small oligopeptide brushes (oligo(S-benzyl-l-cysteine)) onto polyelectrolyte functionalized silica microparticles was developed. Poly(vinyl amine) (PVAm) adsorbed from salt-free and KCl 10⁻¹ mol L⁻¹ aqueous solution onto silica microparticles was chemically and naturally cross-linked by epichlorohydrin and CO₂, respectively. After the adsorption of PVAm onto microporous silica particles and stabilization by cross-linking, five repeated coupling reactions of Boc-S-benzyl-l-cysteine were performed. To test the protein interactions with the newly designed surface, human serum albumin (HSA) has been selected as a model protein. X-ray photoelectron spectroscopy, total organic carbon, potentiometric and polyelectrolyte titrations, and electrokinetic analysis were employed to obtain information about the polyelectrolyte adsorption and the amount of the amino acid S-benzyl-l-cysteine that was covalently bound to the solid surface and for determination of the protein amount adsorbed onto functionalized surface. The amount of HSA adsorbed onto modified silica microparticles decreased in order: silica/PVAm-cross-linked (silica/PVAm-C) (8.00 mg g⁻¹) > silica/PVAm-C/S-benzyl-l-cysteine (6.34 mg g⁻¹) > silica (4.86 mg g⁻¹) > silica/PVAm-C/(S-benzyl-l-cysteine)₅ (1.86 mg g⁻¹).     

Resolution of an intense sweetener mixture by use of a flow injection sensor with on-line solid-phase extraction

An integrated solid-phase spectrophotometry–FIA method is proposed for simultaneous determination of the mixture of saccharin (1,2-benzisothiazol-3(2H)-one-1,1-dioxide; E-954) (SA) and aspartame (N-l-α-aspartyl-l-phenylalanine-1-methyl ester; E-951) (AS). The procedure is based on on-line preconcentration of AS on a C₁₈ silica gel minicolumn and separation from SA, followed by measurement, at λ=210 nm, of the absorbance of SA which is transiently retained on the adsorbent Sephadex G-25 placed in the flow-through cell of a monochannel FIA setup using pH 3.0 orthophosphoric acid–dihydrogen phosphate buffer, 3.75×10^–3 mol L⁻¹, as carrier. Subsequent desorption of AS with methanol enables its determination at λ=205 nm. With a sampling frequency of 10 h⁻¹, the applicable concentration range, the detection limit, and the relative standard deviation were from 1.0 to 200.0 μg mL⁻¹, 0.30 μg mL⁻¹, and 1.0% (80 μg mL⁻¹, n=10), respectively, for SA and from 10.0 to 200.0 μg mL⁻¹, 1.4 μg mL⁻¹, and 1.6% (100 μg mL⁻¹, n=10) for AS. The method was used to determine the amounts of aspartame and saccharin in sweets and drinks. Recovery was always between 99 and 101%. The method enabled satisfactory determination of blends of SA and AS in low-calorie and dietary products and the results were compared with those from an HPLC reference method.     

A Temperature and Salt-Tolerant <Emphasis Type="SmallCaps">l</Emphasis>-Glutaminase from Gangotri Region of Uttarakhand Himalaya: Enzyme Purification and Characterization

Purification and characterization of halotolerant, thermostable alkaline l-glutaminase from a Bacillus sp. LKG-01 (MTCC 10401), isolated from Gangotri region of Uttarakhand Himalaya, is being reported in this paper. Enzyme has been purified 49-fold from cell-free extract with 25% recovery (specific activity 584.2 U/mg protein) by (NH₄)₂SO₄ precipitation followed by anion exchange chromatography and gel filtration. Enzyme has a molecular weight of 66 kDa. l-Glutaminase is most active at pH 11.0 and stable in the pH range 8.0–11.0. Temperature optimum is 70 °C and is completely stable after 3 h pre-incubation at 50 °C. Enzyme reflects more enhanced activity with 1–20% (w/v) NaCl, which is further reduced to 80% when NaCl concentration was increased up to 25%. l-Glutaminase is almost active with K⁺, Zn²⁺, and Ni²⁺ ions and K _m and V _max values of 240 μM and 277.77 ± 1.1 U/mg proteins, respectively. Higher specific activity, purification fold, better halo-tolerance, and thermostability would make this enzyme more attractive for food fermentation with respect to other soil microbe derived l-glutaminase reported so far.