Figure 4
TAG production from unbleached kraft hardwood pulp hydrolysate by R. opacus Xsp8 in batch-culture fermentations. (a) Saccharification of unbleached kraft hardwood pulp using commercially available enzymes. Eighty grams of dried pulp were suspended in 1 liter deionized water and adjusted to a pH 5.0 with 0.1N HCl. Four enzymes, 2 g of Pentopan and 10 ml each of Viscozyme, Celluclast and Novozyme 188, were added into the suspension. After 4, 8 and 12 h of duration, additional 80 g of the pulp, 2 g of Pentopan and 10 ml each of the three enzymes were mixed into the suspension three times. Values and error bars represent the mean and s.d. of triplicate experiments. (b) Time course kinetics of TAG production as fatty acids on the pulp hydrolysate in bioreactor cultivations. Xsp8 was inoculated in the saccharified solution containing 70 g L-1 of total sugars composed of 47 g L-1 glucose, 17 g L-1 xylose and 6 g L-1 other sugars supplemented with 3.47 g L-1 (NH4)2SO4, mineral components of defined medium and gentamicin, at an initial OD660 of 0.5. Values and error bars represent the mean and s.d. of triplicate experiments. (c) Fatty acids composition profile as % of total fatty acids (g g-1) of TAGs from Xsp8 cells growing in the saccharified solution for 7 days. Data are results of triplicate experiments, ±s.d.