The biomass yielding process of xenobiotic degradation.
Yields of activated sludge and an Arthrobacter sp. biomass on organic xenobiotic 2,4-dichlorophenoxyacetic acid (2,4-D) and on the intermediates of selected 2,4-D metabolism pathways were measured. Activated sludge yield on 2,4-D was lower by approximately 24-45% compared to the combined yields produced separately by the lower intermediates. For activated sludge, cell synthesis only consumed 33% of the electrons generated from 2,4-D oxidation, while the other 67% were used for energy. The high energy consumption, which was the primary cause of low activated sludge yield from 2,4-D degradation, occurred mainly in the catabolism of 2,4-D. The degrader sludge supplied this catabolism energy demand with the ATP contained in the biomass. As a result, the sludge's ATP contents suffered a deficit that was not fully remunerated after 2,4-D was degraded. Metabolism of the lower intermediates provided materials for further biomass growth and refilled part of the energy initially consumed.
Department of Environmental Engineering, Da-Yeh University, No. 168, University Rd., Dacun, Changhua 51591, Taiwan, ROC. chong@mail.dyu.edu.tw
Nyuk-Min
NM
Chong
Shiu-Ching
SC
Tsai
Thanh Nga
TN
Le
D015084:2,4-Dichlorophenoxyacetic Acid / Q000378:metabolism; D000064:Acclimatization; D000255:Adenosine Triphosphate / Q000378:metabolism; D001173:Arthrobacter / Q000254:growth & development / Q000378:metabolism; D001673:Biodegradation, Environmental; D018533:Biomass; D002733:Chlorophenols / Q000737:chemistry / Q000378:metabolism; D004583:Electrons; D006038:Glyoxylates / Q000737:chemistry / Q000378:metabolism; D012722:Sewage / Q000382:microbiology; D013816:Thermodynamics; D015262:Xenobiotics / Q000378:metabolism*
D002733:Chlorophenols; D006038:Glyoxylates; D012722:Sewage; D015262:Xenobiotics; D015084:2,4-Dichlorophenoxyacetic Acid; D000255:Adenosine Triphosphate; C031150:glyoxylic acid; C004762:2,4-dichlorophenol