Intergeneric protoplast fusion of yeast for high ethanol production from cheese industry waste – Whey

R. Narayanan Krishnamoorthy^*, K. Vijila and K. Kumutha

Department of Agricultural Microbiology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India, Pin: 641 003.

*Corresponding author. E-mail: krnarayanan_2001@Yahoo.com. Tel: 0422 6611294.  Fax: 0422 6611462.

Accepted 3 June, 2010

Abstract

In this study, Intergeneric protoplast fusion of the yeast cultures Viz., Saccharomyces cerevisiae and Kluyveromyces marxianus  was carried out for enhancing production to ethanol temperature tolerance and lactose utilizing characters in a single stain. S. cerevisiae (Parent 1) has ethanol tolerance, whereas, K. marxianus (Parent 2) is temperature tolerant and also has lactose utilizing capacity. Twelve fused cultures were obtained by protoplast fusion. Fused cultures recorded higher DNA content than the parent strains, which showed complementary banding pattern of two parental Strains. SDS-PAGE confirms the presence of HSP 70 in the fused culture, which is responsible for temperature tolerance. Fermentation of cheese whey was carried out with two parental and fused cultures. The results revealed that the ethanol production was higher with fused culture (12.5%, with 18.09 g/l of biomass) after 72 h of fermentation. Parent 1 showed poor growth on the cheese whey medium, but growth of the Parent 2 was inhibited when the ethanol production reached 6%.

Key words: Marker selection, protoplast fusion, RAPD, SDS-PAGE, whey.