Stillage as a Source of Growth Promoting Biofactors and a Stimulator of Levan and Extracellular Levansucrase Synthesis for Zymomonas mobilis

Martins Bekers*, Mara Grube, Livija Vulfa¹, Dagnija Upite, Elena Kaminska, Rita Scherbaka, Armands Vigants and Aleksejs Danilevich

Institute of Microbiology and Biotechnology, University of Latvia, Kronvalda blvd. 4, LV-1586 Riga, Latvia
¹Faculty of Biology, University of Latvia, Kronvalda blvd. 4, LV-1586 Riga, Latvia

Article history:
Received: May 15, 2002
Accepted: November 7, 2002

Key words:
Zymomonas mobilis, stillage media, vitamins, ethanol, levan, levansucrase

Summary:
In the present work, the fermentation of simultaneous production of ethanol and levan by Zymomonas mobilis grown on different growth media has been studied. Yeast extract, rye stillage or sugar beet molasses stillage were used as additives to the basic sucrose media and the chemical composition, including vitamins, of the cultivation liquids have been determined. It has been shown that 0.5 % of yeast extract dry weight additive could be substituted by 10.0 % of native stillage additive. It was established that molasses stillage stimulates the ethanol synthesis, but rye stillage additive is more preferable for levan production. The extracellular levansucrase obtained from the culture liquid resulted in similar fructooligosaccharide-producing activities using all the above-mentioned media additives. 

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