Microbial mineralization of diisopropanolamine.
Diisopropanolamine (DIPA) is a "sweetening agent" used to remove hydrogen sulfide from sour natural gas, and it is a contaminant at some sour gas treatment facilities in western Canada. To investigate the biodegradation of this alkanolamine, 14C-DIPA was used in anaerobic and aerobic mineralization studies. Between 3 and 78% of the radioactivity from this compound was released as 14CO2 in sediment-enrichment cultures incubated under nitrate-reducing conditions. Similarly, 12-78% of the label was converted to 14CO2 in sediment-enrichment cultures incubated under Mn(IV)-reducing conditions. These activities were observed at 8 degrees C, a typical groundwater temperature in western Canada, and at 28 degrees C. In contrast, DIPA-degrading activity was difficult to sustain under Fe(III)-reducing conditions, and < 25% of the radioactive label from 14C-DIPA was liberated as 14CO2. Two mixed cultures and two isolates (both irregular, non-sporeforming, Gram-positive rods) were used to assess aerobic mineralization of 14C-DIPA. The aerobic mixed cultures released 73 and 79% of the radioactive label as 14CO2, whereas the pure cultures liberated only 39 and 47% as 14CO2. Between one-third and one-half of the nitrogen from DIPA was found as ammonium-N in aerobic batch cultures. These results clearly demonstrate that DIPA is mineralized under a variety of incubation conditions.
Gieg
L M
LM
Department of Biological Sciences, University of Alberta, Edmonton, Canada.
Coy
D L
DL
Fedorak
P M
PM
D000332:Aerobiosis; D000693:Anaerobiosis; D001173:Arthrobacter / Q000254:growth & development / Q000378:metabolism; D001673:Biodegradation, Environmental; D016987:Gram-Positive Rods / Q000254:growth & development / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D011412:Propanolamines / Q000378:metabolism*; D013696:Temperature
D009566:Nitrates; D011412:Propanolamines; C060040:diisopropanolamine; D008345:Manganese; D007501:Iron