ENUMERATION OF SANDY SEDIMENT BACTERIA - SEARCH FOR OPTIMAL PROTOCOL

We examined and compared a variety of existing protocols for enumeration of bacteria from marine sandy sediments. The focus was on how to dislodge bacteria from sediment particles; a commercial blender, an ultrasonic cleaner, and an ultrasonic cell disrupter were tested. The ultrasonic cell disrupter was found to be the most efficient device for bacterial dislodgment. With a 5 mm microtip vibrating at 109 Fun amplitude and 20 kHz, the optimal sonication time of small (less than or equal to 0.5 cm(3)) samples was 180 s. Having identified the optimal dislodgment treatment, we went through other steps of sediment bacteria enumeration (use of surfactants, thoroughness of sample washing, bacterial staining and counterstaining, etc.), striving for additional ways of improvement. The result was a protocol that, in our study, gave bacterial counts superior to those obtained by any other protocol currently in use.