Microbial mineralization of diisopropanolamine

• Published in: Canadian journal of microbiology Vol. 45; no. 5; pp. 377 - 388
• Main Authors: Gieg, L M, Coy, D L, Fedorak, PhM
• Format: Journal Article
• Language: English
• Published: 01.05.1999
• Subjects: Alkanolamine; Canada; Diisopropanolamine
• ISSN: 0008-4166; 1480-3275
• DOI: 10.1139/cjm-45-5-377

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, super(14)C-DIPA was used in anaerobic and aerobic mineralization studies. Between 3 and 78% of the radioactivity from this compound was released as super(14)CO sub(2) in sediment-enrichment cultures incubated under nitrate-reducing conditions. Similarly, 12-78% of the label was converted to super(14)CO sub(2) in sediment-enrichment cultures incubated under Mn(IV)-reducing conditions. These activities were observed at 8 degree C, a typical groundwater temperature in western Canada, and at 28 degree C. In contrast, DIPA-degrading activity was difficult to sustain under Fe(III)-reducing conditions, and <25% of the radioactive label from super(14)C-DIPA was liberated as super(14)CO sub(2). Two mixed cultures and two isolates (both irregular, non-sporeforming. Gram-positive rods) were used to assess aerobic mineralization of super(14)C-DIPA. The aerobic mixed cultures released 73 and 79% of the radioactive label as super(14)CO sub(2), whereas the pure cultures liberated only 39 and 47% as super(14)CO sub(2). 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.