Intrageneric and intergeneric co-aggregation with Acinetobacter calcoaceticus I6

In this note paper, the intergeneric and intrageneric co-aggregation of Acinetobacter calcoaceticus I6 with Bacillus thuringiensis I2 or Candida tropicalis I9 were experimentally elucidated. Auto-aggregation of A. calcoaceticus cells in batch culture and granulation under aerobic environment in a sequential batch reactor fed with phenol-containing medium were examined. The two functionally similar strains (I2 and I6, both are good phenol reducers and auto-flocculators) present high co-aggregation at intermediate phenol level, but fail to coagulate at high level of glucose. The two functionally dissimilar strains (I6 and I9, the latter being a good phenol reducer but a poor flocculator) on the contrary present perfect coagulation at high level of glucose, indicating that the strain I9 exhibits lectin-like receptor for enhancing co-aggregation with I6. Electrostatic repulsion plays no essential role on coagulation for the present intergeneric systems. © 2009 Taiwan Institute of Chemical Engineers.