Purification and characterisation of α-amylase produced by mutant strain of <i>Aspergillus oryzae</i> EMS-18

<div><p>α-Amylase produced by a mutant strain of <i>Aspergillus oryzae</i> EMS-18 has been purified to homogeneity as judged by sodium dodecyle sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was purified by using 70% ammonium sulphate precipitation followed by anion exchange chromatography on DEAE-Sephadex column and gel filtration on Sephadex G-100. An enzyme purification factor of 9.5-fold was achieved with a final specific activity of 1987.7 U/mg protein and overall yield of 23.8%. The molecular weight of purified α-amylase was estimated to be 48 kDa by SDS-PAGE. The purified enzyme revealed an optimum assay temperature and pH 40°C and 5.0, respectively. Except Ca⁺⁺ all other metal ions such as Mg, Mn, Na, Zn, Ni, Fe, Cu, Co and Ba were found to be inhibitory to enzyme activity.</p></div

Enhanced production of xylanase from locally isolated fungal strain using agro-industrial residues under solid-state fermentation

<div><p>This study is related to the isolation of fungal strain for xylanase production using agro-industrial residues. Forty fungal strains with xylanolytic potential were isolated by using xylan agar plates and quantitatively screened in solid-state fermentation. Of all the tested isolates, the strain showing highest ability to produce xylanase was assigned the code <i>Aspergillus niger</i> LCBT-14. For the enhanced production of the enzyme, five different fermentation media were evaluated. Out of all media, M4 containing wheat bran gave maximum enzyme production. Effect of different variables including incubation time, temperature, pH, carbon and nitrogen sources has been investigated. The optimum enzyme production was obtained after 72 h at 30°C and pH 4. Glucose as a carbon source while ammonium sulphate and yeast extract as nitrogen sources gave maximum xylanase production (946 U/mL/min). This study was successful in producing xylanase by <i>A. niger</i> LCBT-14 economically by utilising cheap indigenous substrate.</p></div

Process optimisation for the biosynthesis of cellulase by <i>Bacillus</i> PC-BC6 and its mutant derivative <i>Bacillus</i> N3 using submerged fermentation

<div><p>This study deals with optimisation of cultural conditions for enhanced production of cellulase by <i>Bacillus</i> PC-BC6 and its mutant derivative <i>Bacillus</i> N3. Influence of different variables including incubation time, temperature, inoculum size, pH, nitrogen sources and metal ions has been studied. The optimum conditions for cellulase production were incubation period of 72 h, inoculum size 4% incubation temperature 37°C, pH 7, 0.25% ammonium sulphate, 0.2% peptone as inorganic and organic nitrogen source in case of <i>Bacillus</i> PC-BC6. In case of mutant <i>Bacillus</i> N3, optimal conditions were incubation period of 48 h, incubation temperature 37°C, inoculum size 3%, pH 7, 0.2% ammonium chloride and 0.15% yeast extract. Presence of MnSO₄ and CaCl₂ enhances the enzyme production by <i>Bacillus</i> PC-BC6 and mutant <i>Bacillus</i> N3, respectively. This study was innovative and successful in producing cellulase economically by using cheap indigenous substrate <i>Saccharum spontaneum</i>.</p></div