Poster Presentation 1B-41

 

Lipase Production by Solid State Fermentation: Cultivation Conditions and Operation of a Packed-bed Bioreactor

 

 

Melissa E. L. Gutarra,1 Elisa D. C. Cavalcanti,2
Leda R. Castilho,3 Denise M. G. Freire1* and Geraldo L. Sant’Anna Jr.3

 

 

1 Departamento de Bioquímica – Instituto de Química/UFRJ

2 Instituto de Microbiologia Prof. Paulo de Góes/UFRJ

3 Programa de Engenharia Química - COPPE/UFRJ

 

 

 

In recent years, research on lipases has increased because of their wide range of application in many industries such as food, pharmaceutical and detergent.  These enzymes can be produced by submerged fermentation (SF) or by solid-state fermentation (SSF).  Interest in SSF has also increased due to the availability of low-cost carbon-energy sources like agricultural residues.

 

This work investigated the production of lipase by Penicillium simplicissimum, utilizing crushed babassu cake as solid cultivation medium.  The fermentation was carried out in trays and in bench-scale packed-bed bioreactors.  Cultivation conditions were investigated through factorial designed experiments conducted in trays.  Different supplementary carbon sources (olive oil and molasses) and nitrogen sources (corn steep liquor and hydrolyzed yeast) were tested at several concentrations.  The effect of temperature and initial moisture content on lipase production was also investigated.  The results showed that the variables temperature, moisture content and carbon source concentration had a significant effect on lipase production, while the influence of the nitrogen source concentration on enzyme production was not statistically significant.  Additional experiments showed that the supplementation of babassu cake with molasses led to lipase activity values, which were similar to those obtained with olive oil supplementation.  Thus, the most adequate conditions for lipase production were: cultivation medium constituted of babassu cake supplemented with molasses; temperature and moisture content of 30 oC and 70%, respectively.

 

These conditions were tested in the packed-bed bioreactor, which consisted of a jacketed column reactor (14-cm of bed-height and 4-cm of internal diameter) aerated with humidified air. The effects of temperature and air-flow rate on lipase production were investigated.  A decrease of 50% on lipase activity was observed when the temperature was raised from 29oC to 35oC, whereas an appreciable increase on lipase production resulted from the specific air-flow rate increase (from 8 to 80 cm/min).  Under the best operating conditions the maximum lipase activity and the process productivity were, respectively, 21 U/g and 0.44 U/g.h.