Simplest way to convert glucose into water and carbon dioxide other than burning? What is the simplest pathway from glucose to $\ce{H2O}$ and $\ce{CO2}$, such that 


all reactions happen in aqueous solution with pH between 5 and 8, 
temperature is in range between 0 and 35 °C, 
no (expensive) enzymes are required, 
the reaction is completed in around 6 hours, and
no toxic or harmful intermediates are formed and no toxic or harmful catalysts are used? 


I realize that one possible answer to this would be, in biochemistry, 

glycolysis &rarr; pyruvate decarboxylation &rarr; citric acid cycle &rarr; oxidative phosphorylation; 

this is a fairly complex reaction cascade, however. Is there a way chemistry could simplify this in comparable (more or less physiological) conditions? 

Aside from a possible (retro-)synthetic approach, there might be a catalytic option. I've found a publication by Degering and Upson* that describes iron pyrophosphate as a catalyst, but the reaction times are far higher (around 3 weeks), the temperature is relatively high and the reaction appears to be relatively messy in terms of products. 

* Edward F. Degering and Fred W. Upson, J. Biol. Chem. 1931, 94, 423-431. DOI: n/a; URL: http://www.jbc.org/content/94/2/423.short (pdf) (no https available)
I'd suggest you read into the Fenton process. Using an iron catalyst with hydrogen peroxide will break down (potentially) any organic matter into $\ce{CO2}$ and $\ce{H2O}$ within minutes or hours. The only drawback from your requirements is the pH, since I think this is only down in acidic solution, but you could do a little research to find out more.