Optimizing Growth Conditions of Kluyveromyces marxianus for Mannan Production as a Bioemulsifier

Mannan which is a linear glycoprotein with β-1,4 links carrying mannose units bind to proteins, includes natural amphiphiles and serves as a bioemulsifier. The aim of this study was optimization of growth and purification ofKluyveromyces marxianusfor mannan production, which can use as a natural bioemulisifier.

In this study, mannan production by Kluyveromyces marxianuswas assessed using combinational method of fractional factorial design and response surface methodology optimization. Process variables include concentration of carbon source (15, 30, 45 g l-1)of glucose, and glycerol and methanol at 0, 2.5 and 5 gl-1), nitrogen source (yeast extract and peptone 4, 6 and 8 gl-1), as well as fermentation time (48, 96 and 144 h), pH (4, 6, 8) and agitation speed (150, 200 and 250 rpm).

Results showed that four variables of carbon and nitrogen source concentrations, as well as fermentation time and pH included the greatest effects on mannan production. Optimization of the affecting factors using response surface methodology demonstrated appropriate conditions of mannan production by Kluyveromyces marxianusas 55.15 g l-1of glucose, 9.35 g l-1of yeast extract, pH of 4.99 and fermentation time of 168 h, which led to a mannan yield of 245.98mg(100ml)-1culture media.