BARC/PUB/2015/0220

 
 

Biodegradation of tributyl phosphate, an organosphate triester, by aerobic granular biofilms

 
     
 
Author(s)

Nancharaiah, Y. V.; Reddy, G. K. K.; Mohan, T. V. K.; Venugopalan, V. P.
(W&SCD)

Source

Journal of Hazardous Materials, 2015. Vol. 283: pp. 705-711

ABSTRACT

Tributyl phosphate (TBP) is commercially used in large volumes for reprocessing of spent nuclear fuel. TBP is a very stable compound and persistent in natural environments and it is not removed in conventional waste water treatment plants. In this study, cultivation of aerobic granular bio films in a sequencing batch reactor was investigated for efficient biodegradation of TBP. Enrichment of TBP-degrading strains resulted in efficient degradation of TBP as sole carbon or along with acetate. Complete biodegradation of 2mM of TBP was achieved within 5h with a degradation rate of 0.4μmolmL−1h−1. TBP biodegradation was accompanied by release of inorganic phosphate in stoichiometric amounts. n-Butanol, hydrolysed product of TBP was rapidly biodegraded. But, dibutyl phosphate, a putative intermediate of TBP degradation was only partially degraded pointing to an alternative degradation pathway. Phosphatase activity was 22- and 7.5-fold higher in TBP-degrading biofilms as compared to bioflocs and acetate-fed aerobic granules. Community analysis by terminal restriction length polymorphism revealed presence of 30 different bacterial strains. Seven bacterial stains, including Sphingobium sp. a known TBP degrader were isolated. The results show that aerobic granular biofilms are promising for treatment of TBP-bearing wastes or ex situ bioremediation of TBP-contaminated sites.

 
 
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