Monitoring of phosphorus bioavailability in water by an immobilized luminescent cyanobacterial reporter strain

Massive growth of cyanobacteria, known as 'algal blooms', has become a majo r concern for water monitoring. It has been observed that environmental fac tors like temperature, light, and certain patterns of availability of nutri ents such as P, N, Fe influence cyanobacterial proliferation and toxin prod uction. In order to monitor nutrients in aquatic ecosystems, an assay for m onitoring phosphorus bioavailability to cyanobacteria was developed. The te st consists of an immobilized luminescent reporter strain of Synechococcus PCC 7942, designated APL. The reporter strain harbours the gene coding the reporter protein luciferase from Vibrio harveyi under control of the induci ble alkaline phosphatase promoter from Synechococcus PCC 7942, and can be i nduced under phosphorus limitation. The resultant CyanoSensor detects PO43- -P in a concentration range of 0.3-8 muM after a sample incubation time of 8 h under continuous illumination (50 muE m(-2) s(-1)). The sensor also re sponded to a variety of organic phosphorus sources and was storable for 3 w eeks at 4 degreesC. It could be demonstrated that the CyanoSensor for bioav ailability monitoring is an improvement to conventional phosphorus detectio n methods. (C) 2001 Elsevier Science B.V. All rights reserved.