Evaluation of the liquid, solid and total fractions of beer, cider and wine lees as economic nutrient for xylitol production

BACKGROUND The final prices of fermentative culture broths must be reduced in order to extend biotechnological processes to an industrial scale. In this way, residual lees from the beer, cider and wine industries were evaluated as a source of nitrogen and micronutrients for xylitol production by Debaryomyces hansenii. RESULTS The liquid fraction of wine or beer lees was employed as suitable culture media for xylitol production (QP = 0.30–0.24 g L−1 h−1, respectively). Complete beer lees diluted to 25% produced 27.2 g L−1 after 168 h (QP = 0.16 g L−1 h−1). Autolysis of beer lees produced 15.6 g L−1 of xylitol using whole lees (QP = 0.11 g L−1 h−1), or 34.8 g L−1 using the solid fraction (QP = 0.36 g L−1 h−1). The specific xylitol productivity (0.12 g g−1 h−1) achieved with the solid fraction was even higher than that obtained with the synthetic control (qP = 0.074 g g−1 h−1). CONCLUSIONS Residual lees can be used as economical nutrients. In some cases, autolysis treatments are necessary to increase the amount of available nitrogen thus improving the fermentative parameters. © 2014 Society of Chemical Industry