Ethanol Production from Sugarcane Bagasse Hydrolysate Using Pichia stipitis

摘要

The objective of this study was to evaluate the ethanol production from thesugars contained in the sugarcane bagasse hemicellulosic hydrolysate with the yeast Pichiastipitis DSM 3651. The fermentations were carried out in 250-mL Erlenmeyers with100 mL of medium incubated at 200 rpm and 30 °C for 120 h. The medium was composedby raw (non-detoxified) hydrolysate or by hydrolysates detoxified by pH alterationfollowed by active charcoal adsorption or by adsorption into ion-exchange resins, all ofthem supplemented with yeast extract (3 g/L), malt extract (3 g/L), and peptone (5 g/L).The initial concentration of cells was 3 g/L. According to the results, the detoxificationprocedures removed inhibitory compounds from the hemicellulosic hydrolysate and, thus,improved the bioconversion of the sugars into ethanol. The fermentation using the nondetoxifiedhydrolysate led to 4.9 g/L ethanol in 120 h, with a yield of 0.20 g/g and aproductivity of 0.04 g L?1 h?1. The detoxification by pH alteration and active charcoaladsorption led to 6.1 g/L ethanol in 48 h, with a yield of 0.30 g/g and a productivity of0.13 g L?1 h?1. The detoxification by adsorption into ion-exchange resins, in turn, provided7.5 g/L ethanol in 48 h, with a yield of 0.30 g/g and a productivity of 0.16 g L?1 h?1.