Tuesday, April 20, 2010
11-27
Mathematical models of cashew apple bagasse hydrolizate fermentation by Kluyveromyces marxianus CE025 to produce ethanol and xylitol
Maria Valderez Ponte Rocha, Chemical Engineering, Universidade Federal Rural do Semi-Árido, BR 110 - Km 47 Bairro Pres. Costa e Silva, Mossoró, Brazil, Luciana R. B. Goncalves, Chemical Engineering, Universidade Federal do Ceará, Campus do Pici, Bloco 709, Fortaleza, Brazil, Vania M.M. Melo, Biology Departament, Universidade Federal do Ceará, Campus do Pici, Bloco 909, Fortaleza, Brazil, and Gorete de Ribeiro Macedo, Chemical Engineering, Universidade Federal do Rio Grande do Norte, Av. Sen. Salgado Filho 3000, Natal, Brazil.
In the state of Ceará (Northeast of Brazil), the cashew agroindustry has an outstanding role in the local economy and the cashew apple bagasse (CAB) appears as an alternative lignocellulosic waste for ethanol and xylitol production. The yeasts traditionally used in fermentation processes are able to consume hexoses as substrate but not pentoses. Nevertheless, it is important to look for yeasts which also have the capacity to consume this pentose, such as Kluyveromyces marxianus that is capable of transforming D-xylose into useful bioproducts (ethanol and xylitol). Therefore, in this work, a mathematical model of the fermentation of CAB hydrolyzate by Kluyveromyces marxianus CE025 to produce ethanol and xylitol was proposed. Experimental data were collected through specifically designed fermentations in order to identify the parameters of the model. All experiments were performed in a batch-culture reactor, keeping aeration level and pH of the culture medium (4.5) constant. Maximum specific net growth rate (μm), biomass productivity (b), the specific rates of xylose uptake (qs), ethanol and xylitol production (qE and qXy) and overall yields in biomass (YGx/s), ethanol (YGE/s) and xylitol (YGXy/s) were determined. Parameter values were obtained by a technique of non-linear regression, using the free software SCILAB version 5.1. The kinetic models described satisfactorily the batch fermentation process as demonstrated by the results.
See more of Poster Session Two
See more of General Submissions
See more of The 32nd Symposium on Biotechnology for Fuels and Chemicals (April 19-22, 2010)
See more of General Submissions
See more of The 32nd Symposium on Biotechnology for Fuels and Chemicals (April 19-22, 2010)