ISSN:
1432-0614
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Summary Zymomonas mobilis ATCC 29191 is able to degrade gluconate but cannot use it as a single carbon and energy source. Gluconate is phosphorylated by a gluconate kinase (EC 2.7.1.12) and the resulting 6-phosphogluconate is further catabolized to yield about 0.8 mol ethanol per mol of gluconate, considerable amounts of acetate and acetoin. This product spectrum agrees with the theoretical yield of only one reduction equivalent if gluconate is phosphorylated by a kinase and subsequently metabolized via the Entner-Doudoroff pathway. Furthermore, Z. mobilis contains a membrane-bound enzyme system which is able to oxidize glucose to gluconate. Cell-free extracts were active in an assay system with Wurster's blue as electron acceptor, and various aldoses as well as maltose, mannitol and sorbitol could be oxidized. The affinity for sorbitol was very low (K m =330 mM) but reasonable for glucose (K m =2.8 mM). The pH optimum for the glucose-oxidizing reaction was 6.5, while that for sorbitol oxidation was 5.5.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00251772
