Abstract - Improvement of SCP production and BOD removal of whey with mixed yeast culture

Microbial Biotechnology

Electronic Journal of Biotechnology ISSN: 0717-3458	Vol. 7 No. 3, Issue of December 15, 2004
© 2004 by Pontificia Universidad Católica de Valparaíso -- Chile	Received January 26 , 2004 / Accepted August 11, 2004

Improvement of SCP production and BOD removal of whey with mixed yeast culture

Hassan Moeini
Department of Biology
Faculty of Science
Shahid Chamran University
Ahvaz, Iran
Tel/Fax: 98 611 3331045
E-mail: hamo40@yahoo.com

Iraj Nahvi*
Department of Biology
Faculty of Science
Shahid Chamran University
Ahvaz, Iran
Tel/Fax: 98 311 7932456
E-mail: I.nahvi@sci.ui.ac.ir

Manoochehr Tavassoli
Department of Biology
Faculty of Science
Shahid Chamran University
Ahvaz, Iran
Tel/Fax: 98 311 7932456
E-mail: manoochehrt@yahoo.com

*Corresponding author

Financial support:Isfahan University.

Keywords: beta-galactosidase,BOD, Candida versatilis, Kluyveromyces lactis, Kluyveromyces marxianus, mixed culture, SCP, whey.

Abbreviations:	SPC: Single Cell Protein; BOD: Biochemical Oxygen Demand; MEB: Malt Extract Broth; YGCA: Yeast extract, Glucose, Chloramphenicol and Agar; PDA:Potato Dextrose Agar.

This research emphasizes on single cell protein (SCP) production and Biochemical Oxygen Demand (BOD) removal from whey with mixed yeast culture. For this purpose, 11 yeast strains were isolated from dairy products (M1-M11) and the strains were identified by morphological and physiological properties. These yeast strains were tested for their ability to reduce the BOD and to produce SCP from whey. Among these strains, K. lactis (M2) had the most SCP production from whey with the yield of 11.79 g/l. Ammonium sulphate as nitrogen source had an increasing effect on biomass yield. The mixed culture of the isolated yeast strains with Saccharomyces cerevisiae was used in order to increase the biomass yield and BOD removal. The highest biomass yield (22.38 g/l) and reduction of initial BOD from 30000 to 3450 mg/l were obtained with the mixed culture of K. lactis (M2) and S. cerevisiae.