White wine production effluents used for biotechnological production of xanthan

Abstract

This paper examines xanthan production by Xanthomonas campestris on wastewater obtained from different white wine production process sections - crushing, pressing, clarification of must and fermentation. Wastewater was analyzed for basic nutrients content and, if required it was enriched or diluted to contain amounts suitable for xanthan biosynthesis. Biosynthesis was performed in a laboratory-scale bioreactor under identical conditions for all four studied wastewaters. In order to determine if the performed biosynthesis was successful, xanthan yield was determined gravimetrically and sugar conversion was calculated based on initial and residual HPLC values of sugar content. Obtained xanthan yield was in the range of 4.0 to 10.67 g/L while the value of sugar conversion ranged between 62.74 and 68.83 %. Different viscosities of the cultivation media at the end of the process were also compared. Due to the fact that the synthesized xanthan had both different yields and viscosities, it can be concluded that different fractions of winery wastewater yield different amounts of xanthan of different quality.

Keywords

• environmental protection
• winery wastewaters
• biotechnological process
• xanthan production
• xanthomonas campestris