Microbial Biotechnology

Electronic Journal of Biotechnology ISSN: 0717-3458 Vol. 10 No. 4, Issue of October 15, 2007
© 2007 by Pontificia Universidad Católica de Valparaíso -- Chile Received March 2, 2007 / Accepted May 24, 2007
DOI: 10.2225/vol10-issue4-fulltext-10
RESEARCH ARTICLE

Optimization of medium composition for transglutaminase production by a Brazilian soil Streptomyces sp.

Juliana Alves Macedo*
Food Science Department
Faculty of Food Engineering
Universidade Estadual de Campinas
P.O. Box 6121, CEP 13083-862
SP, Brazil
Tel: 55 19 3521 2175
Fax: 55 19 3521 2153
E-mail: jmacedo@fea.unicamp.br 

Lara Durães Sette
Brazilian Collection of Environmental and Industrial Microorganisms
Microbial Resource Division
CPQBA, Universidade Estadual de Campinas
P.O. Box 6171, CEP 13081-970
SP, Brazil
Tel: 55 19 3884 7500
E-mail: lara@cpqba.unicamp.br

Hélia Harumi Sato
Food Science Department
Faculty of Food Engineering
Universidade Estadual de Campinas
P.O. Box 6121, CEP 13083-862
SP, Brazil
Tel: 55 19 3521 2165
E-mail: heliah@fea.unicamp.br

*Corresponding author

Financial support: The authors wish to thank CNPq and Microbial Resource Division (CPQBA/UNICAMP) for their financial support.

Keywords: central composite design, fractional factorial design, medium optimization, microbial transglutaminase, Streptomyces sp. P20.

Abbreviations:

ANOVA: analysis of variances
CCD: central composite design
FFD: fractional factorial design
MTGase: microbial transglutaminase
RSM: response surface methodology
TGase: transglutaminase

Abstract
Full Text

Finding a new microbial source of transglutaminase (MTGase) and the study of the medium composition for MTGase production were the goals of this work. A total of 200 actinomycete-like strains were isolated from Brazilian soil samples and two of them named T10b and P20 were selected based on their ability to produce 0.15 U.mL-1 and 0.25 U.mL-1 of MTGase, respectively. Strain P20 was chosen to continue the study and was identified as Streptomyces sp. In order to optimize the MTGase activity, modifications of the usual media composition described for enzyme production were tested. The strategy adopted was: (1) screening experiment for the best carbon and nitrogen sources; (2) fractional factorial design (FFD) to elucidate the key ingredients in the media (the results indicated that the soybean flour, peptone, KH2PO4 and MgSO4.7H2O had a significant effect on MTGase) production and (3) central composite design (CCD) to optimize the concentration of the key components. The experimental results were fitted to a second-order polynomial model at the 95% level of significance (P < 0.05). Under the proposed optimized conditions, the model predicted a MTGase activity of 1.37 U.mL-1, very closely matching the experimental activity of 1.4 U.mL-1.

Supported by UNESCO / MIRCEN network