Utilization of chlorinated s-triazines by a new strain of Klebsiella pneumoniae.

A bacterium utilizing 2-chloro-4,6-diamino-s-triazine (CAAT) as sole nitrogen source was isolated under a N2-free atmosphere and identified as Klebsiella pneumoniae. Concomitant to CAAT degradation the protein content increased and chloride was released into the medium. Under air and a N2-atmosphere no reduction of CAAT degradation resulted, though this strain is able to fix molecular nitrogen, but the decomposition accelerated under anaerobic conditions. The degradation rate increased continuously with increasing CAAT concentration. A continuous CAAT degradation without CAAT accumulation was possible up to a influx rate of 4.8 mumol.l-1h-1 (dilution rate = 0.007 h-1). K. pneumoniae A2 was also able to utilize deethylsimazine (CEAT) and deethylatrazine (CIAT) as nitrogen source. Both under aerobic and anaerobic conditions CEAT could be degraded faster than CIAT. The degradation sequence of mixed s-triazines was cyanuric acid < CAAT < CEAT < CIAT, which was reflected by the degradation times of single compounds. Complete degradation was assumed for all investigated s-triazine derivatives.