Estudo comparativo da produção de etanol por processos de SHF (Fermentação e Hidrólise Separadas) e SSF (Fermentação e Hidrólise Simultâneas) de bagaço de caju (Anacardium accidentale L.)

• Ano de defesa: 2014
• Autor(a) principal: Rodrigues, Tigressa Helena Soares
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Engenharia química; Fermentação alcoólica; Bagaço de caju
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/10913

In this work, the ethanol production from cashew bagasse was studied after acid followed by alkali pretreatment (CAB-OH) using the Separate Hydrolysis and Fermentation (SHF) and Simultaneous Saccharification and Fermentation (SSF) processes. In SHF process, the hydrolysate obtained from enzymatic hydrolysis of CAB-OH was used as carbon source for fermentation with different strains of Saccharomyces (S. cerevisiae CCA008, S. cerevisiae 01, S. cerevisiae 02 and Saccharomyces sp. 1238), Kluyveromyces (K. marxianus CCA510, CE025 and ATCC36907) and Hanseniaspora sp. GPBio03. The bioprocess was conducted at 30 °C and 50 g.L-1 initial glucose concentration. The K. marxianus ATCC36907 achieved ethanol concentration of 20 g.L-1 with consumption of all glucose in the hydrolysate. Similar results were obtained with Saccharomyces strains and higher ethanol concentration (23.43 g.L-1) was obtained by Saccharomyces sp. 1238. The maximum ethanol concentration of 24.54 g.L-1 was achieved by Hanseniaspora sp. GPBio03. Focused on further studies using SSF process, it was evaluated the temperature influence of thermotolerant yeast K. marxianus ATCC36907 in glucose and enzymatic hydrolysate from CAB-OH. The results showed that the temperature (30, 35, 40, 45 and 50 °C) did not affect the values of YE/G (0.45 to 0.46 gethanol/gglucose) using glucose as substrate. Moreover, the ethanol yields obtained with enzymatic hydrolysate were slightly influenced by temperature, 0.39 and 0.43 gethanol/gglucose were obtained at 30 and 40 °C, respectively. Based on this, the SSF of CAB-OH and K. marxianus ATCC36907 was conducted at 40 °C with cellulases from Celluclast 1.5L at 15 FPU/gcellulose. The highest ethanol concentration (24.90 ± 0.89 g.L-1) was obtained with 76h of fermentation with 0.33 g.L-1.h-1, 0.34 gethanol/gglucose and 66.3% of productivity, YʹE/G and of ethanol efficiency, respectively. In enzymatic hydrolysis studies, the cellulase NS 22074 at 30 FPU/gcellulose without cellobiases supplementation resulted in glucose yield of 93.77 ± 2.72% which is promising for studies of SSF with this enzyme complex. The temperature (40, 42 , 45 and 50 °C) influence in SSF process using microcrystalline cellulose, in contrast with SHF results, higher ethanol concentration, 19.86 ± 0.32 g.L-1, was obtained at 40 °C. The SSF using CAB-OH, 30 FPU/gcellulose cellulases NS 22074 at 40 °C showed higher ethanol concentration of 37.35 ± 0.64 g.L-1 at 80h, with productivity of 0.46 g.L-1.h-1. In this condition, there was an increase of YʹE/G from 0.34 to 0.49 gethanol/gglucose and the ethanol efficiency from 66.3% to 95.59% when compared to results obtained with SSF using Celluclast 1.5L. Based on the results of efficiency and ethanol yield (YʹE/G), the cashew apple bagasse showed as lignocelulose feedstock promising material for second generation ethanol production by SSF process using the yeast K. marxianus ATCC36907 and NS 22074 cellulases complex.