BIOAUGMENTATION WITH THE RESIN ACID-DEGRADING BACTERIUM ZOOGLOEA RESINIPHILA DhA-35 TO COUNTERACT PH STRESS IN AN AERATED LAGOON TREATING PULP AND PAPER MILL EFFLUENT

Removal assays of resin acids such as dehydroabietic acid(DhA) which are the major toxicants in pulp and paper effluents and form pitch interfering with papermaking. Low and high pH stresses (pH 3 and 10 respectively) decreased the removal of DhA by the biomass of an aerated lagoon treating pulp mill effluent. The pH stresses caused changes in the bacterial community structure and greatly reduced the indigenous DhA-degrading population in the lagoon community. Bioaugmentation with zoogloea resiniphila DhA-35 degrading bacterium restored the DhA removal in both low and high pH-stressed lagoon biomass.