BIODEGRADATION OF 2-FURALDEHYDE UNDER NITRATE-REDUCING AND METHANOGENIC CONDITIONS

Nitrate‐reducing and methanogenic microbial consortia capable of using 2‐furaldehyde (furfural) as a sole source of carbon and energy were isolated from a mixture of soil and municipal sewage and from municipal anaerobic digestor sludge, respectively. Under nitrate‐reducing conditions, more than 97% of the furfural was biodegraded in 0.25, 1.5, 4 and 32 d at initial substrate concentrations of 0.5, 5, 50 and 500 ppm, respectively. In all cases microbial populations were able to reduce furfural levels to less than the detection limit of 20 ppb as measured by HPLC. At 500 ppm, there was a 12‐d lag period before detectable activity was noted, while there was no lag period at the lower concentrations tested. When the disappearance of both furfural (50 ppm) and nitrate was measured, the molar ratio of nitrate to furfural consumed was approximately 4.2:1, Which is in good agreement with the theoretical ratio of 4.0:1. The biodegradation of furfural was generally more rapid under methanogenic than under nitrate‐reducing conditions. The methanogenic consortium was able to metabolize 97% of the furfural in 2, 4, 48 and 144 h at initial concentrations of 0.5, 5, 50 and 500 ppm, respectively. No lag period was noted at any concentrations tested. As under nitrate‐reducing conditions, populations were able to reduce furfural levels to less than 20 ppb. Complete metabolism of furfural in cultures that received an initial concentration of 50 ppm resulted in the production of 0.056 mM methane or 43% of the theoretical yield that would result from complete conversion of the material to carbon dioxide and methane. This is the first report of the biodegradation of furfural under nitrate‐reducing conditions. Copyright © 1990 SETAC