title: Bioconversion of glucose and fructose to sorbitol and gluconic acid by untreated cells of Zymomonas mobilis.
abstract: The bioconversion of glucose and fructose to gluconic acid and sorbitol, respectively, by the enzymes glucose-fructose oxidoreductase (GFOR) and glucono-delta-lactonase (GL), contained in untreated cells of Zymomonas mobilis ATCC 29191, was investigated in batch runs with glucose plus fructose concentrations (S0) varying from 100 to 750 g l-1 in equimolar ratio. When S0 was increased to 650 g l-1, the yields were improved, reaching a maximum of 91% for both products, with productivities of 1.6 and 1.5 g g-1 cell h-1 for gluconic acid and sorbitol, respectively. Above this level (S0 = 750 g l-1), no further improvement in yields was observed and productivities decreased due to the longer process time. The high yields of bioconversion runs with S0 > or = 650 g l-1 are a consequence of the sequential inhibition of the normal metabolism of Z. mobilis by substrates and products, resulting in preferential utilization of substrates via the GFOR/GL system.
authors.affiliation: Centro de Desenvolvimento Biotecnológico, Joinville, SC, Brazil.
authors.forename: M M
authors.initials: MM
authors.lastname: Silveira
authors.forename: E
authors.initials: E
authors.lastname: Wisbeck
authors.forename: C
authors.initials: C
authors.lastname: Lemmel
authors.forename: G
authors.initials: G
authors.lastname: Erzinger
authors.forename: J P
authors.initials: JP
authors.lastname: da Costa
authors.forename: M
authors.initials: M
authors.lastname: Bertasso
authors.forename: R
authors.initials: R
authors.lastname: Jonas
mesh_terms: D005285:Fermentation; D005632:Fructose / Q000378:metabolism*; D005942:Gluconates / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D013012:Sorbitol / Q000378:metabolism*; D017355:Zymomonas / Q000254:growth & development / Q000378:metabolism*
chemical_list: D005942:Gluconates; D005632:Fructose; D013012:Sorbitol; D005947:Glucose; C030691:gluconic acid