The characteristics and kinetics of whole-cell catalysis were investigated individually or simultaneously relative to the bio-oxidation of five monosaccharides to corresponding aldonic acids using Gluconobacter oxydans. For individual catalysis, 30 g/L glucose could be consumed completely at 3.21 g/L/h in 8 h, and arabinose was the slowestconsumed at 1.18 g/L/h in 8 h. Among five monosaccharides, the yield of xylonic acid was highest at 90.4%, and about 31.0 g/L xylonic acid could be obtained

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... 24 h. For simultaneous catalysis, a complex substrate competition appeared in the mixed-aldoses solution. The utilization rate of arabinose, galactose, xylose and mannose were repressed distinctly. And glucose exhibited variable inhibitory effects on the remaining four monosaccharides utilization. Higher concentration of mixed aldoses showed a tendency to minimize the difference of glucose inhibition on arabinose, galactose, xylose, and mannose conversion to corresponding acids. Thus, the total concentration and proportion between various aldoses should be properly controlled for a highly efficient production of aldonic acids from lignocellulosic material.