The development of a Bacillus subtilis 168 culture condition for enhanced and accelerated beta-mannanase production.
A shaken flask cultivation condition for enhanced and accelerated beta-mannanase formation by Bacillus subtilis 168 was achieved. Among five examined fermentation media a formula that supported enzyme generation and retarded biomass yield and sporulation was selected. The deficiency of biomass production in this medium was mastered by choosing a seed culture medium that accelerated growth and initiation of beta-mannanase synthesis. With respect to enzyme production, the optimum pH and temperature were 7 and 37 degrees C, respectively. The biosynthesis of the enzyme was extremely influenced by the cell growth state as a modulator, glucose as a catabolite repressor, and galactomannan as an inducer. A galactomannan concentration of 4 g l-1 induced a beta-mannanase activity level of 17.5 U ml-1 after 24 h of incubation at the experimental condition. Higher inducer concentrations supported growth rather than enzyme production. The influence of inoculum size was so remarkable that, at optimum, a crude filtrate with an enzyme activity of 33U ml-1 was yielded within 4 hours. It appears that this is among the highest rates reported for beta-mannanase production. We have also demonstrated that blocking of the sporulation process at stage II do not affect enzyme production significantly. This would allow an extended enzyme production phase especially in a continuous culture.
el-Helow
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ER
Department of Botany and Microbiology, Faculty of Science, Alexandria, Egypt.
Khattab
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AA
D001412:Bacillus subtilis / Q000201:enzymology* / Q000254:growth & development; D002244:Carbon; D003470:Culture Media; D004790:Enzyme Induction; D005285:Fermentation; D005690:Galactose / Q000031:analogs & derivatives; D006863:Hydrogen-Ion Concentration; D008351:Mannans / Q000494:pharmacology; D008361:Mannosidases / Q000096:biosynthesis*; D013171:Spores, Bacterial; D013379:Substrate Specificity; D013696:Temperature; D044902:beta-Mannosidase
D003470:Culture Media; D008351:Mannans; C012990:galactomannan; D002244:Carbon; D008361:Mannosidases; D044902:beta-Mannosidase; D005690:Galactose