Abstract: High temperature processes and thermophilic organisms for use in those processes for reducing the levels of certain nitrogen-containing compounds in tobacco materials. Tobacco materials are contacted with at least one thermophilic organism characterized by an anaerobic, dissimilatory, metabolic pathway for denitrification of tobacco materials under anaerobic and high temperature conditions that promote such metabolism. Tobacco materials treated in accordance with these high temperature processes and thermophilic organisms, when incorporated into a smoking product, deliver a significantly reduced amount of oxide of nitrogen in smoke. Moreover, such tobacco materials also afford the product of other tobacco products having lower amounts of nitrates and other nitrogen-containing compounds.