Lytic enzyme production optimization using low-cost substrates and its application in the clarification of xanthan gum culture broth
Article first published online: 25 APR 2014
© 2014 The Authors. Food Science & Nutrition published by Wiley Periodicals, Inc.
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Food Science & Nutrition
Volume 2, Issue 4, pages 299–307, July 2014
How to Cite
Food Science & Nutrition 2014; 2(4): 299–307
- Issue published online: 11 JUL 2014
- Article first published online: 25 APR 2014
- Manuscript Accepted: 12 DEC 2013
- Manuscript Revised: 21 NOV 2013
- Manuscript Received: 12 SEP 2013
- Fundação de Amparo à Pesquisa do Estado da Bahia
- Aspergillus tamarii ;
- gram-negative bacteria;
- response surface methodology
Lytic enzymes are widely used in industrial biotechnology as they are able to hydrolyze the bacterial cell wall. One application of these enzymes is the clarification of the culture broth for the production of xanthan gum, because of its viability in viscous media and high specificity. The screening process for filamentous fungi producing lytic enzymes, the optimization of production of these enzymes by the selected microorganism, and the optimization of the application of the enzymes produced in the clarification of culture broth are presented in this article. Eleven fungal isolates were tested for their ability to produce enzymes able to increase the transmittance of the culture broth containing cells of Xanthomonas campestris. To optimize the secretion of lytic enzymes by the selected microorganism the following variables were tested: solid substrate, initial pH, incubation temperature, and addition of inducer (gelatin). Thereafter, secretion of the enzymes over time of incubation was assessed. To optimize the clarification process a central composite rotational design was applied in which the pH of the reaction medium, the dilution of the broth, and the reaction temperature were evaluated. The isolate identified as Aspergillus tamarii was selected for increasing the transmittance of the broth from 2.1% to 54.8%. The best conditions for cultivation of this microorganism were: use of coconut husk as solid substrate, with 90% moisture, at 30°C for 20 days. The lytic enzymes produced thereby were able to increase the transmittance of the culture broth from 2.1% to 70.6% at 65°C, without dilution and without pH adjustment.