Production of fuel ethanol: effects of free nitrogen on the fermentation of very high gravity sugar cane juice

• Grant number: 09/54109-8
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2010
• End date: March 31, 2012
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Technology
• Principal Investigator: André Ricardo Alcarde
• Grantee: André Ricardo Alcarde
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

The objective of this project is to verify the influence of nitrogenous supplementation on fermentative parameters of very high gravity sugar cane juice. The nitrogen plays an essential role on yeast physiology and in very high gravity fermentations allows higher productivity and yield. It also protects yeast cells against osmotic and ethanolic stress. High gravity sugar cane juices at 25, 30 e 35° brix, supplemented with l6mM of urea, will be fermented at 30°C by yeasts Saccharomyces cerevisiae (strains PE-2, BG-1, CAT-1 and SA-1) for 6 fermentative cycles. The wines will be analysed for the concentrations of assimilable nitrogen, ethanol and residual sugars. The yeasts will be analysed for cell viability. It is expected that the supplementation of the juice with 16mM of urea allow complete and faster fermentations, reaching higher ethanol concentrations. It is also expected that the yeasts maintain their viability during the fermentative recycles. (AU)