Production of hepatotoxin cylindrospermopsin in the batch culture of cyanobacterium Cylindrospermopsis raciborskii

Abstract

A toxic cyanobacterium Cylindrospermopsis raciborskii was grown in batch culture under initial nitrogen concentrations of 1mg · l^-1 and 16.5 mg · l^-1 as nitrate and production of hepatotoxin cylindrospermopsin (CYN) was investigated. CYN increased with increase of density of C. raciborskii and maximum concentrations of CYN were 0.45 mg CYN · l^-1 and 1.26 mg CYN · l^-1 at initial NO₃-N concentrations of 1mg · l^-1 and 16.5 mg · l^-1 respectively. At initial NO₃-N concentration of 1mg · l^-1, total nitrogen concentration increased to 7 mg · l^-1 showing occurrence of nitrogen fixation. CYN concentration correlated with total nitrogen concentration under initial NO₃-N concentration of 1mg · l^-1. It was suggested that C. raciborskii and CYN might increase by nitrogen fixation in nitrogen limited lakes and reservoirs.