Proposed pathway for δ-gluconolactone metabolism in S. bulderi. 1, glucose dehydrogenase; 2, hexokinase; 3, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase; 4, rearrangement reactions in the pentose phosphate pathway via transaldolase and transketolase; 5, glycolysis. GAP, glyceraldehyde-3-phosphate.