Role of cyanobacteria in the removal of lignin from the paper mill waste waters

Most pulp and paper mills in India discharged partially treated waste waters, causing considerable pollution of receiving waters. The ability of 2 cyanobacteria (Phormidium ambiguum and Chroococcus minutus) to degrade lignin in daylight under aseptic conditions at 30C was investigated. Both organisms reduced the concentrations of lignin, sulphate, phosphate, and nitrate in pulp mill wastewater diluted 1:3 (by volume). Algal growth and removal of lignin were maximal on day 5, and the rate of removal of lignin decreased thereafter. The possible mechanisms involved in lignin degradation are indicated.