Mineralization of aminobenzenesulfonates by a newly isolated bacterial co-culture (AS1 and AS2)

Aminobenzenesulfonates (ABS) are important building blocks of azo dyes and are used in the manufacture of fewpharmaceuticals and pesticides. Thus, they are synthesized in large quantities and released into the environmentthrough wastewaters emanating from these industries. Xenobiotic character of ABS renders these compoundsresistant to degradation by unadapt activated sludge and bacterial species utilizing normal aromatics. Degradation ofABS isomers by a co-culture of Agrobacterium sp. strain PNS-1 and 2-ABS degrading bacterial consortium (BC) wasstudied. Among the ABS isomers, strain PNS-1 could only utilize 4-ABS as the growth substrate, whereas BC (AS1 &AS2) could degrade only 2-ABS. The co-culture, however, could completely mineralize both these isomers, whereas3-ABS was not degraded. Studies on the effect of the presence of glucose, an easily assimilable and non-toxicsubstrate, on the degradation of 2- and 4-ABS by the co-culture showed that 4-ABS degradation rate was notsignificantly affected, whereas decrease was observed in 2-ABS removal rate. These observations show that a mixedABS can only be mineralized by co-cultures of specialized bacterial strains, as individual strains have a very limitedsubstrate range.