INFLUENCE OF TEMPERATURE ON ALKALINE PHOSPHATASE ACTIVITY IN CYANOBACTERIA (BLUEGREEN ALGAE)

The enzyme alkaline phosphatase (APase), which catalyzes the degradation of complex organic phosphate substrates into 
organic moiety and biologically available inorganic phosphate (Pi), plays an important role in the growth and survival of 
cyanobacteria under the conditions of phosphorous deficiency in the ambient environment. APase activity serves as an 
indicator of phosphorus status in phytoplanktons. Various physicochemical factors can influence alkaline phosphatase activity 
in cyanobacteria. The present study was undertaken to investigate the influence of varying temperature in the range 10-50 °C
on alkaline phosphatase (cellular and extracellular PMEase) activity in two freshwater cyanobacteria Synechocystis sp. 
(unicellular form) and Oscillatoria sp. (filamentous non-heterocystous form). In both the cyanobacteria, cellular and 
extracellular PMEase were observed to be maximally active at temperature 35°C and 40°C, respectively. The activity of 
cellular PMEase increased with the increase in temperature from 10oC to 35oC and thereafter decreased abruptly. The activity 
of extracellular PMEase increased up to 40oC followed by a drastic decrease beyond 40oC. The results of the study indicate 
that temperature is an important environmental factor influencing cyanobacterial APase activity.