Strategies for improving extracellular lipolytic enzyme production by Thermus thermophilus HB27

Bioresour Technol. 2009 Jul;100(14):3630-7. doi: 10.1016/j.biortech.2009.02.053. Epub 2009 Apr 1.

Abstract

In Thermus thermophilus HB27 cultures the localisation of lipolytic activity is extracellular, intracellular and membrane bound, with low percentage for the former. Therefore, the extracellular secretion must be increased in order to simplify the downstream process and to reduce the economic cost. This study focuses on the design of an innovative operational strategy to increase extracellular lipolytic enzyme production by T. thermophilus HB27 at bioreactor scale. In order to favour its secretion, the effect of several operational variables was evaluated. Among them, the presence of oils in the culture medium leads to improvements in growth and lipolytic enzyme activity. Sunflower oil is the most efficient inducer showing better results when added after 10h of growth. On the other hand, although surfactants lead to an almost complete inhibition of growth and lipolytic enzyme production, their addition along the culture could affect the location of the enzyme. Thus, by addition of surfactants at the stationary phase, a release of intracellular and membrane enzyme which increases the extracellular enzyme proportion is detected. Based on these results, strategies with successive addition of oil and surfactant in several culture phases in shake flask are developed and verified in a laboratory scale stirred tank bioreactor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bioreactors
  • Biotechnology / methods*
  • Culture Media / metabolism
  • Detergents / pharmacology
  • Gases
  • Helianthus / metabolism
  • Hydrogen-Ion Concentration
  • Industrial Microbiology / economics
  • Industrial Microbiology / methods*
  • Kinetics
  • Lipase / metabolism
  • Lipids / chemistry
  • Oxygen / metabolism
  • Plant Oils / metabolism
  • Surface-Active Agents / chemistry
  • Thermus / cytology
  • Thermus / enzymology*
  • Thermus / growth & development

Substances

  • Culture Media
  • Detergents
  • Gases
  • Lipids
  • Plant Oils
  • Surface-Active Agents
  • Lipase
  • Oxygen