Utilization of sugar cane bagasse hemicellulosic hydrolysate by Pichia stipitis for the production of ethanol
Roberto, I.C.; Lacis, L.S.; Barbosa, M.F.S.; Mancilha, I.M. de
Process Biochemistry 26(1): 15-21
ISSN/ISBN: 1359-5113 DOI: 10.1016/0032-9592(91)80003-8
Fresh sugarcane bagasse was impregnated with 35 mM H2SO4 (solid:liquid ratio 1:6) for 16 h, then subjected to steam-explosion at 190 degrees C for 5 min; the hydrolysate was adjusted to pH 5.0 with NaOH (which gave better results than KOH or CaO) and decolorized for 1 h at 30 degrees with 200 g activated carbon/litre. Standard nutrients were added and the medium was fermented at 30 degrees with P. stipitis CBS 5773 (3 x 107 cells/ml) for 72-96 h. Previous tests on synthetic media showed that this organism converted xylose to ethanol much more efficiently than Candida utilis, C. tropicalis or Pachysolen tannophilus; substrate inhibition was negligible below 100 g/litre.