|
Poster Presentation 6-21
The Effect of Aeration on Lignin Peroxidase Production by Streptomyces viridosporus T7A
Leda M.F. Gottschalk1, Ronaldo Nobrega1, Elba P.S. Bon,2
1 Programa de Engenharia Química, COPPE Universidade Federal do Rio de Janeiro, RJ, Brazil
2 Departamento de Bioquímica, IQ Universidade Federal do Rio de Janeiro Rio de Janeiro, RJ, Brasil
Telephone: (55) 021-2652-7358; E-mail: leda@peq.coppe.ufrj.br
Lignin peroxidase (LiP) has potential use in environmental biocatalysis due its ability to oxidize a wide range of aromatic substances including the recalcitrant compounds such as chlorolignin, pesticides, and azo dies. In this work the effect of aeration on LiP production by S. viridosporus T7A was studied in an instrumented 3-L bench scale fermenter using a previously optimized growth medium containing 0.65% yeast extract, 0.1% corn oil, and mineral salts. Air flow rates of 0.3, 1.0 and 1.5 vvm were examined at a constant agitation rate of 200 rpm; agitation rates were also varied (200, 200, 400, and 500 rpm) to measure their effect with a constant air flow rate of 1.0 vvm. Using 1.0 and 1.5 vvm at 200 rpm yielded peak LiP activity in 24 hours, and the highest enzyme concentration (1600 U/g cell) was observed using 1.0 vvm. The use of 1.0 vvm and 400 rpm increased enzyme concentration 1.8 fold (100 to 180 U/L) and the process productivity 4 fold (1.4 to 5.6 U/L/h), in comparison to the use of 200 rpm and 0.3 vvm. Considering that an insoluble carbon source (corn oil) was used, the optimized agitation was beneficial for both the cell oxygen uptake as well as to allow greater availability of this carbon source to the Streptomyces cells.
|