Hyper-production of levansucrase from Zymomonas mobilis KIBGEIB14 using submerged fermentation technique.

The industrial utilization of enzymes requires the high yield of enzyme production for the synthesis of polymers by microorganisms. Therefore, it is necessary to optimize different production parameters of levansucrase in order to increase its industrial applications. Zymomonas mobilis KIBGE-IB14 was considered as a promising candidate for the large scale production of levan among wide range of microorganisms. The current investigation is aimed to optimize the production parameters of levansucrase by Z. mobilis KIBGE-IB14 isolated from molasses. The results indicated that bacterial growth as well as enzyme production was greatly influenced by both physical and chemical conditions. It was revealed that high enzyme titers were achieved at 30°C with pH 6.5 after 24 hours of incubation in a modified medium. Moreover, the enzyme exhibited its induction in the presence of sucrose used as a substrate. Thus, the present study demonstrated that newly isolated Z. mobilis KIBGE-IB14 can be used as a plausible producer of levansucrase for industrial applications.

Synthesis, characterization and enzyme inhibitory activity of new pyrazinamide iron complexes.

The present paper deals with synthesis, characterization and amylase inhibitory activity of pyrazinamide (PYZ) with iron in its both (II) and (III) oxidation states. The synthesized complexes were characterized on the basis of IR, UV, 1H-NMR, 13C-NMR, elemental analysis and SEM. Changes in IR data shows that PYZ form complex with octahedral geometry and binding sites are ring nitrogen and carbonyl group, wherein two sides are satisfied with two chloride ions. SEM images indicate the crystalline state and surface morphology of PYZ and its complexes. Elemental analysis proves the composition of complexes. Pyrazinamide and the complexes showed no significant effect on amylase activity but the activity was inhibited in the presence of ferrous chloride.

Influence of different metals on the activation and inhibition of α-amylase from thermophilic Bacillus firmus KIBGE-IB28.

Thermophilic Bacillus firmus KIBGE-IB28 produced extracellular α-amylase at temperature 70°C. Enzyme was partially purified by ammonium sulfate precipitation with 42.80 fold purification and specific activity of 1889.6 U/mg. Effects of various metals on enzyme activity were determined and it was found that enzyme activity boosted significantly in presence of Ca(2+), K(2+), Ba(2+), Co(2+) and Ni(2+) whereas Zn(2+), Mg(2+), Na(2+) and Cu(2+) were found inhibitory at concentration 10mM.

Role of nutrients and environmental conditions for the production of dextransucrase from L. mesenteroides KIBGE-IB26.

The bacterial strains capable of producing dextransucrase enzyme were isolated from different fruits and vegetables sources. In primary screening, five strains were selected on the basis dextransucrase production and among them L. mesenteroides KIBGE- IB26 isolated from bottle gourd (Lagenaria Vulgaris) was selected for further studies. For the enhancement of enzyme production, different physicochemical parameters were optimized. Maximum production of dextransucrase was achieved after 06 hrs using sucrose (20.0 g/l) as a substrate at 25°C. Maximum dextransucrase production was achieved when medium pH was kept 7.5 before sterilization. In addition, medium was also supplemented with CaCl2 and K2HPO4 and maximum enzyme production was achieved at 0.0025 g/dl calcium chloride and 2.0 g/dl K2HPO4with enzyme activity of 87 DSU/ml/hr. Production of dextransucrase in shorter period of time makes this strain an attractive candidate for commercial production of dextransucrase.

Plasmid borne BAC-IB17: Localization of a potential antibacterial positive marker (Bac+) encoded broad inhibitory spectrum bacteriocin.

Production of antimicrobial compounds is considered as ubiquitous anti-competitor strategy in bacterial ecosystem. Bacteriocins are heterogeneous; highly specific and efficient anti-competitor agents and the gene responsible for the production of bacteriocins mostly exist in an autosomal state and associated with plasmids. BAC-IB17 is a broad spectrum bacteriocin and its production was observed at different stages of the growth cycle from Bacillus subtilis KIBGE-IB17. Growth kinetics of B. subtilis KIBGE-IB17 along with the production of BAC-IB17 showed that it exhibited secondary metabolite kinetics. Plasmid curing technique revealed that the gene responsible for the bacteriocinogenecity in B. subtilis KIBGE-IB17 was located on the plasmid of the bacterium. Overlay method also demonstrated the plasmid-mediated bacteriocinogenesis of the isolated colonies. With the advancement in genomics and proteomics, the plasmid borne BAC-IB17 can play a significant role in the transfer of bacteriocinogenic factor to other incompetent cells and also in the maintenance of plasmid in bacterial population.