Ruthenium supported on nitrogen-doped mesorporous carbons (NMC) catalyzed hydrolytic hydrogenation of alginic acid to produce C6 sugar alcohols, mainly sorbitol and mannitol. Nitrogen contents were controlled by changing the weight ratio of urea/glucose and carbonization temperature. The highest yield of target C6 sugar alcohols was 50.3% (sorbitol: 24.3% and mannitol: 26.0%) at 180 degrees C for 1 h over Ru(5)/NMC(0.1)(600), where 0.1 and 600 were the urea/glucose ratio and carbonization temperature (degrees C), respectively. The intimate interaction between Ru and the support induced by nitrogen doping resulted in suppression of byproduct formation such as C4-C5 sugar alcohols and galactitol. Moreover, the interaction as evidenced by various analytical techniques resulted in the excellent durability of the catalyst after repeated reactions without severe leaching or aggregation of Ru.