Process Biotechnology
 

Microbial Biotechnology

Electronic Journal of Biotechnology ISSN: 0717-3458 Vol. 11 No. 1, Issue of January 15, 2008
© 2008 by Pontificia Universidad Católica de Valparaíso -- Chile Received February 28, 2007 / Accepted July 20, 2007
DOI: 10.2225/vol11-issue1-fulltext-13
RESEARCH ARTICLE

Role of PPase-SE in Geotrichum klebahnii, a yeast-like fungus able to solubilize pectin

Natalia Lorena Rojas
Centro de Investigación y Desarrollo en Fermentaciones Industriales
Facultad de Ciencias Exactas
Universidad Nacional de La Plata
Calle 47 y 115, (1900) La Plata, Argentina
Tel/Fax: 54 221 483 3794
E-mail: rojas@biotec.org.ar

Sebastián Fernando Cavalitto
Centro de Investigación y Desarrollo en Fermentaciones Industriales
Facultad de Ciencias Exactas
Universidad Nacional de La Plata
Calle 47 y 115, (1900) La Plata, Argentina
Tel/Fax: 54 221 483 3794
E-mail: cavali@biotec.org.ar

Carlos Fernando Mignone
Centro de Investigación y Desarrollo en Fermentaciones Industriales
Facultad de Ciencias Exactas
Universidad Nacional de La Plata
Calle 47 y 115, (1900) La Plata, Argentina
Tel/Fax: 54 221 483 3794
E-mail: mignone@biotec.org.ar

Roque Alberto Hours*
Centro de Investigación y Desarrollo en Fermentaciones Industriales
Facultad de Ciencias Exactas
Universidad Nacional de La Plata
Calle 47 y 115, (1900) La Plata, Argentina
Tel/Fax: 54 221 483 3794
E-mail: hours@biotec.org.ar

Website: http://www.cindefi.org.ar

*Corresponding author

Financial support: This work was supported by Grants for Scientific Research from La Plata National University (11/X304) and the Argentine National Agency for the Promotion of Science and Technology (PICT99 # 14-07288).

Keywords: carbon balance, enzymatic pectin extraction, microbial pectin utilization, pectinases, synthetic medium.

Abbreviations:

CES: carbon and energy sources
GALA: D-Galacturonic acid monohydrate
HM: high methoxyl
HPLC: High Performance Liquid Chromatography
MM: maintenance medium
PGA: polygalacturonic acid
PPases: Protopectinases
RM: reference medium

Abstract   Full Text

Protopectinases (PPases) constitute a heterogeneous group of extracellular enzymes able to release soluble pectin from insoluble protopectin in plant tissues. Geotrichum klebahnii (ATCC 42397) produces PPase-SE with endopolygalacturonase activity. PPase-SE has been used for pectin extraction and maceration of plant tissues. Here, the capacity of G. klebahnii to use different pectins as carbon and energy sources (CES) was studied, in addition to PPase-SE capacity to release pectin from lemon peel. The strain was unable to use pectin from different origins as CES. When G. klebahnii was cultivated with mixtures of different amounts of glucose and citrus pectin as CES, the biomass obtained was proportional to the initial concentration of glucose, which was completely consumed. In addition, it produced PPase-SE in a glucose-containing medium. A culture was used for the extraction of pectin from lemon peels. Pectin was enzymatically extracted simultaneously with tissue maceration, yielding 3.7 g of (dry) pectin per 100 g of (wet) lemon peel. Extracted pectin was not metabolized by the strain. It was concluded that G. klebahnii uses PPase-SE to macerate, invade and colonize plant tissues, thus releasing soluble sugars to be used as CES without metabolizing solubilized pectin.

Supported by UNESCO / MIRCEN network