title: Sodium dodecyl sulphate, a strong inducer of thermostable glucanhydrolase secretion from a derepressed mutant strain of Bacillus alcalophilus GCBNA-4.
abstract: In the present study, we report the optimisation of batch conditions for improved α-1,4-glucan-glucanohydrolase (GGH) secretion by a nitrous acid (NA)-treated Bacillus alcalophilus. The wild (isolate GCB-18) and NA-derivative (mutant GCBNA-4) were grown in a medium containing 10 g/L nutrient broth, 10 g/L starch, 5 g/L lactose, 2 g/L ammonium sulphate, 2 g/L CaCl2 and phosphate buffer (pH 7.6). Sodium dodecyl sulphate (SDS) was used as an enzyme inducer while batch fermentations were carried out at 40 °C. The mutant produced GGH in 40 h which was 15-fold higher than the wild in presence of SDS. Thermodynamic studies revealed that the mutant culture exhibited the capability for improved enzyme activity over a broad range of temperature (35-70 °C). The enzyme was purified by cation-exchange column chromatography with ~80 % recovery. The performance of fuzzy-logic system control was found to be highly promising for the improved substrate conversion rate. The correlation (1.045E + 0025) among variables demonstrated the model terms as highly significant indicating commercial utility of the culture used (P < 0.05).
authors: Department of Botany, GC University, Lahore, Pakistan.
authors: Nadia
authors: N
authors: Shamim
authors: Sikander
authors: S
authors: Ali
authors: Ikram
authors: I
authors: Ul-Haq
mesh_terms: D001407:Bacillus / Q000187:drug effects* / Q000201:enzymology*; D004795:Enzyme Stability / Q000187:drug effects; D005959:Glucosidases / Q000235:genetics / Q000378:metabolism*; D009608:Nitrous Acid / Q000494:pharmacology; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology*; D013696:Temperature
chemical_list: D012967:Sodium Dodecyl Sulfate; C028287:2-O-alpha-D-glucopyranosyl-O-beta-D-galactopyranosyl-hydroxylysine glucohydrolase; D005959:Glucosidases; D009608:Nitrous Acid