Effects of Carbon Sources on Production of Leucine Aminopeptidase and Activities of Sugar Metabolic Enzymes Produced by Bacillus cereus CZ
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
Leucine aminopeptidase (LAP) produced by Bacillus cereus CZ was investigated in this study. Results indicated that L-arabinose was the best carbon source for producing LAP, followed by D-galactose and lactose, whereas glucose, maltose, sucrose and sodium bicarbonate obviously inhibited LAP production. The production of LAP was also reduced largely when L-arabinose was mixed with other simple sugars, or Lactose/ D-galactose was mixed with glucose. The mixture of lactose and glucose was the optimal carbon sources for cell growth.When using 2% lactose, D-galactose and L-arabinose as carbon sources, LAP activities did not reach the maximum values after 48 h fermentation. For the sugar metabolic enzymes, β-galactosidase can be strongly induced by lactose. L-Arabinose had certain induction effect, while D-galactose had a strong depression effect. Galactokinase was induced significantly by D-galactose, followed by L-arabinose and lactose. L-arabinoseisomerase was induced strongly by L-arabinose, moderately by other simple sugars and mixed sugars. LAP production reached the highest with 4% L-arabinose and D-galactose. Extracelluar galactokinase decreased with increasing the sugar concentration, but intracellular enzymes showed the reverse trend. L-arabinoseisomerase increased with increasing concentration of L-arabinose. LAP production reached the highest when fermentation for 56 h with 4% L-arabinose. However, its production increased continuously with fermentation time when 4% D-galactose was used.
