Influence of Metal ions, Surfactants and Organic Solvents on the Catalytic Performance of Levansucrase from Zymomonas mobilis KIBGE-IB14

A significant progress has been made in discovering and developing new bacterial polysaccharides producing enzymes possessing extremely functional properties. Levan is a natural polymer of fructose linked by β (2→6) glycosidic bond which is produced by transfructosylation reaction in the presence of levansucrase. Among wide range of microorganisms, Zymomonas mobilis is considered as the most promising candidate for the production of extracellular levansucrase. It has potential applications in multiple industries from pharmaceutics, cosmetics to food industries. Determination of levansucrase characteristics is necessary to increase its industrial applications. This concept has directed much interest towards enzyme characterization by observing its effects against different chemicals. The present investigation focused on the characterization of levansucrase by observing its behavior with reference to different metal ions, surfactants and organic solvents. The results showed that these chemicals acted as activators, inhibitors or stabilizers. In metal ions, different activators (K+, Na+, Cs+, Ba+2, Ca+2, Cu+2, Mg+2 and Mn+2 ) and inhibitors (Co+2, Hg+2 , Fe+3and Al+3) were investigated. Among them, Hg+2 found to be strong inhibitor as it inhibits enzyme activity by 92% at 1 mM. Non-ionic surfactants i.e. triton X-100, tween-20 and tween-80 considered as stabilizers while anionic surfactant such as sodium dodecyl sulphate (SDS) inhibited the enzyme activity by 11%. Moreover, ethanol and methanol stabilized the enzyme activity while other solvents observed as inhibitors or stimulators

Utilization of corncob xylan as a sole carbon source for the biosynthesis of endo-1,4-β xylanase from Aspergillus niger KIBGE-IB36

Abstract Background Xylan is a hemicellulose polysaccharide which is composed of β-1,4-linked d-xylosyl residues. Endo-1,4-β xylanase has the ability to cleave xylan back bone chains to release xylose residues. They are produced by a number of prokaryotic and eukaryotic organisms. Among them, filamentous fungi are attracting great attention due to high secretion of xylanolytic enzymes. Endo-1,4-β xylanase has wide industrial applications such as in animal feed, bread making, food and beverages, textile, bleaching of wood pulp, and biofuel production. Results In this study, different Aspergillus species were screened for the production of endo-1,4-β xylanase, and Aspergillus niger KIBGE-IB36 was selected for optimum production of enzyme in submerged fermentation technique. Influence of various fermentation conditions was investigated to produce high titer of endo-1,4-β xylanase. The results indicated that A. niger KIBGE-IB36 showed optimum production of endo-1,4-β xylanase at 30 °C, pH 8 after 6 days of incubation. Different macro- and micronutrients were also amalgamated in the fermentation medium to increase the enzyme production. The parametric optimization of endo-1,4-β xylanase resulted in tenfold increase after hydrolysis of 20 g L−1 corncob xylan. Conclusions The use of low-cost substrate approach for high production of endo-1,4-β xylanase has been developed successfully that can be consumed in different industrial applications especially in paper and pulp industry. Graphical abstract Production of Xylanase from Aspergillus niger KIBGE-IB36

Effect of Metal Ions, Solvents and Surfactants on the Activity of Protease from Aspergillus niger KIBGE-IB36

Metal ions greatly impact on the enzymatic activity, they may form strong interaction by forming coordinate bond with enzyme-substrate at the catalytic site which may activate, inhibit or stabilized the enzyme molecules. In this study, extracellular protease from Aspergillus niger KIBGE-IB36 was precipitated with 40% ammonium sulfate. It was revealed that K+, Ba2+, Na+, Mg2+ Zn2+, Ca2+ boosted the protease activity whereas, Cs+, Mn2+, Cu2+, Ni2+, V2+, Co2+, Hg2+ and Al3+ showed to be inhibitor of protease. Dimethyl sulfoxide (5.0 mM) and methanol (5.0 mM) showed catalytic activity while ethanol at same concentration exhibited inhibitory effect. Protease activity augmented with Tween 80, while SDS, Triton X-100, EDTA and PMSF exhibited inhibitory effect

Effect of Metal Ions, Solvents and Surfactants on the Activity of Protease from Aspergillus niger KIBGE-IB36

Metal ions greatly impact on the enzymatic activity, they may form strong interaction by forming coordinate bond with enzyme-substrate at the catalytic site which may activate, inhibit or stabilized the enzyme molecules. In this study, extracellular protease from Aspergillus niger KIBGE-IB36 was precipitated with 40% ammonium sulfate. It was revealed that K+, Ba2+, Na+, Mg2+ Zn2+, Ca2+ boosted the protease activity whereas, Cs+, Mn2+, Cu2+, Ni2+, V2+, Co2+, Hg2+ and Al3+ showed to be inhibitor of protease. Dimethyl sulfoxide (5.0 mM) and methanol (5.0 mM) showed catalytic activity while ethanol at same concentration exhibited inhibitory effect. Protease activity augmented with Tween 80, while SDS, Triton X-100, EDTA and PMSF exhibited inhibitory effect

Immobilization of Dextranase Using Anionic Natural Polymer Alginate as a Matrix for the Degradation of a Long-Chain Biopolymer (Dextran)

Alginate is an inexpensive, nontoxic, valuable biopolymer utilized in the study for the immobilization of commercially applicable biocatalyst dextranase. Dextranase was immobilized by an entrapment method, and alginate hydrogel spheres were synthesized after optimizing several parameters. A sodium alginate concentration of 4.0% was noticed to be suitable along with a calcium chloride concentration of 0.2 molar after providing a curing time of 20 minutes. After comparing the characteristics of the entrapped enzyme with those of the soluble one, it was observed that the characteristics were more or less the same except for the change in reaction time which was noticed to be prolonged in the case of entrapped dextranase while the change in temperature and pH optima was not observed. The variation in Vmax and Km values of dextranase after entrapment was also noted. However, after extensive stability examination studies, it was found that dextranase became more stable after entrapment; as a result, it retained more than 50% of its original activity at elevated temperature even after exposure for about 2.0 hours. The reusability of dextranase was up to 7.0 cycles after performing catalytic activity under constant condition

Partial purification and some properties of <img src='/image/spc_char/alpha.gif'>-amylase from <i style="">Bacillus</i> <i style="">subtilis</i> KIBGE-HAS

401-404 An extracellular -amylase from Bacillus subtilis KIBGE-HAS was partially purified by ultrafiltration and ammonium sulphate precipitation with 19.2-fold purification and specific activity of 4195 U/mg. The enzyme showed relatively high thermostability and retained 62% of its activity when kept at 70°C for 15 min. -Amylase was highly stable at -18°C and loss of activity was very low during stability study. Metal ions like Mn2+, Ca2+, Co2+, K+, Mg2+, and Fe3+ activated the enzyme, while Hg2+ Ba2+, Cu2+, Na+ and Al3+ strongly inhibited the activity. The α-amylase was highly stable in various surfactants and detergents. In the presence of surfactants such as SDS and Triton X-100 the enzyme activity was found 2.9 and 1.8-fold higher respectively than control. The non-ionic detergents (Tween 20 and Tween 80) exhibited slightly inhibitory effect on the enzyme activity.</smarttagtype

Production &#38; Characterization of a Unique Dextran from an Indigenous Leuconostoc mesenteroides CMG713

On the basis of high enzyme activity a newly isolated strain of L. mesenteroides CMG713 was selected for dextran production. For maximum yield of dextran, effects of various parameters such as pH, temperature, sucrose concentration and incubation period were studied. L. mesenteroides CMG713 produced maximum dextran after 20 hours of incubation at 30&#186;C with 15% sucrose at pH 7.0. The molecular mass distribution of dextran produced by this strain showed that its molecular mass was about 2.0 million Da. Dextran analysis by 13C-NMR spectrometry showed no signals corresponding to any other linkages except &#945;-(1&#8594;6) glycosidic linkage in the main chain, which has not been reported before. Physico-chemical properties of this unique dextran were also studied. These optimised conditions could be used for the commercial production of this unique high molecular weight dextran, which have significant industrial perspectives.</p