Improvement of ethanol production from sweet sorghum juice under batch and fed-batch fermentations: effects of sugar levels, nitrogen supplementation, and feeding regimes
Electron. j. biotechnol
; Electron. j. biotechnol;26: 84-92, Mar. 2017. graf, tab
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| ID: biblio-1008992
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ABSTRACT
Background:
Fermentation process development has been very important for efficient ethanol production. Improvement of ethanol production efficiency from sweet sorghum juice (SSJ) under normal gravity (NG, 160 g/L of sugar), high gravity (HG, 200 and 240 g/L of sugar) and very high gravity (VHG, 280 and 320 g/L of sugar) conditions by nutrient supplementation and alternative feeding regimes (batch and fed-batch systems) was investigated using a highly ethanol-tolerant strain, Saccharomyces cerevisiae NP01.Results:
In the batch fermentations without yeast extract, HG fermentation at 200 g/L of sugar showed the highest ethanol concentration (PE, 90.0 g/L) and ethanol productivity (QE, 1.25 g/L·h). With yeast extract supplementation (9 g/L), the ethanol production efficiency increased at all sugar concentrations. The highest PE (112.5 g/L) and QE (1.56 g/L·h) were observed with the VHG fermentation at 280 g/L of sugar. In the fed-batch fermentations, two feeding regimes, i.e., stepwise and continuous feedings, were studied at sugar concentrations of 280 g/L. Continuous feeding gave better results with the highest PE and QE of 112.9 g/L and 2.35 g/L·h, respectively, at a feeding time of 9 h and feeding rate of 40 g sugar/h.Conclusions:
In the batch fermentation, nitrogen supplementation resulted in 4 to 32 g/L increases in ethanol production, depending on the initial sugar level in the SSJ. Under the VHG condition, with sufficient nitrogen, the fed-batch fermentation with continuous feeding resulted in a similar PE and increased QP by 51% compared to those in the batch fermentation.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
LILACS
Assunto principal:
Sorghum
/
Etanol
/
Biocombustíveis
/
Fermentação
Idioma:
En
Revista:
Electron. j. biotechnol
Assunto da revista:
BIOTECNOLOGIA
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Tailândia
País de publicação:
Chile