Zymomonas mobilis as catalyst for the biotechnological production of sorbitol and gluconic acid.
The conversion of glucose and fructose into gluconic acid (GA) and sorbitol (SOR) was conducted in a batch reactor with free (CTAB-treated or not) or immobilized cells of Zymomonas mobilis. High yields (more than 90%) of gluconic acid and sorbitol were attained at initial substrate concentration of 600 g/L (glucose plus fructose at 1:1 ratio), using cells with glucose-fructose-oxidoreductase activity of 75 U/L. The concentration of the products varied hyperbolically with time according to the equations (GA) = t (GA)max /(W(GA) + t), (SOR) = t (SOR)max/(W(SOR) + t), V(GA) = [W(GA) (GA)max]/(W(GA) + t)2 and V(SOR) = [W(SOR) (SOR)max]/(W(SOR) + t)2. Taking the test carried out with free CTAB-treated cells as an example, the constant parameters were (GA)max = 541 g/L, (SOR)max = 552 g/L, WGA = 4.8 h, W(SOR) = 4.9 h, v(GA) = 112.7 g/L x h and v(SOR) = 112.7 g/L x h.
Erzinger
Gilmar Sidney
GS
University of Joinville, Pharmacy School, Santa Catarina, SC, Brazil.
Vitolo
Michele
M
D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology / Q000379:methods; D003198:Computer Simulation; D005240:Feasibility Studies; D005632:Fructose / Q000378:metabolism*; D005942:Gluconates / Q000302:isolation & purification / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D008954:Models, Biological; D010865:Pilot Projects; D013012:Sorbitol / Q000302:isolation & purification / Q000378:metabolism*; D017355:Zymomonas / Q000378:metabolism*
D005942:Gluconates; D005632:Fructose; D013012:Sorbitol; D005947:Glucose; C030691:gluconic acid