Cashew apple bagasse as a source of sugars for ethanol production by Kluyveromyces marxianus CE025.
The potential of cashew apple bagasse as a source of sugars for ethanol production by Kluyveromyces marxianus CE025 was evaluated in this work. This strain was preliminarily cultivated in a synthetic medium containing glucose and xylose and was able to produce ethanol and xylitol at pH 4.5. Next, cashew apple bagasse hydrolysate (CABH) was prepared by a diluted sulfuric acid pretreatment and used as fermentation media. This hydrolysate is rich in glucose, xylose, and arabinose and contains traces of formic acid and acetic acid. In batch fermentations of CABH at pH 4.5, the strain produced only ethanol. The effects of temperature on the kinetic parameters of ethanol fermentation by K. marxianus CE025 using CABH were also evaluated. Maximum specific growth rate (μ(max)), overall yields of ethanol based on glucose consumption [Formula: see text] and based on glucose + xylose consumption (Y ( P/S )), overall yield of ethanol based on biomass (Y ( P/X )), and ethanol productivity (P (E)) were determined as a function of temperature. Best results of ethanol production were achieved at 30°C, which is also quite close to the optimum temperature for the formation of biomass. The process yielded 12.36 ± 0.06 g l(-1) of ethanol with a volumetric production rate of 0.257 ± 0.002 g l(-1) h(-1) and an ethanol yield of 0.417 ± 0.003 g g(-1) glucose.
Departamento de Agrotecnologia e Ciências Sociais, Universidade Federal Rural do Semi-Árido, Av. Francisco Mota, 572, Costa e Silva, Mossoró, RN, 59.625-900, Brazil. valderez@ufersa.edu.br
Maria Valderez Ponte
MV
Rocha
Tigressa Helena Soares
TH
Rodrigues
Vania M M
VM
Melo
Luciana R B
LR
Gonçalves
Gorete Ribeiro
GR
de Macedo
D031021:Anacardium / Q000378:metabolism*; D001089:Arabinose / Q000378:metabolism; D056804:Biofuels / Q000191:economics; D018533:Biomass; D001709:Biotechnology; D002482:Cellulose / Q000378:metabolism*; D003246:Conservation of Energy Resources; D000431:Ethanol / Q000191:economics / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D007716:Kluyveromyces / Q000378:metabolism*; D013464:Sulfuric Acids / Q000737:chemistry; D014993:Xylitol / Q000378:metabolism; D014994:Xylose
D056804:Biofuels; D013464:Sulfuric Acids; D000431:Ethanol; D002482:Cellulose; C027433:bagasse; D014994:Xylose; D001089:Arabinose; D005947:Glucose; C033158:sulfuric acid; D014993:Xylitol