Extracellular enzymes of cyanobacteria Nodularia spumigena, Microcystis aeruginosa and green alga Mychonastes homosphaera

Abstract

This study focused on the profiles of extracellular enzyme activity from cyanobacteria and green algae. The working hypothesis of this study is 'cyanobacteria and green alga have different extracellular enzyme profiles, and respond to environmental conditions with different extracellular enzyme activity'. A total of 17 extracellular enzymes was investigated for axenic laboratory strains of two cyanobacteria Nodularia spumigena (N. spumigena) and Microcystis aeruginosa (M aeruginosa), and one green alga Mychonastes homosphaera (M. homosphaera). The methods were based on using fluorescently labeled substrates and a 96-well Spectraflurplus microplate reader. Extracellular enzymes investigated in the study included laurate esterase, caprylate esterase, propionate esterase, butyrate esterase, acetate esterase, phosphatase, sulfatase, glucuronidase, cellobiosidase, a-glucosidase, B-glucosidase, xylosidase, B-fucosidase, B-galactosidase, B-N-acetylglucosaminidase, guanidinobenzoate protease, and leucine aminopeptidase. The cultures were grown in modified BG11 media. The effect of total darkness, reduce phosphorus (0.001-1mg/L) and nitrogen (0.01-1mg/L), and mixed culture were investigated in relation to the extracellular enzyme profile. The location of these extracellular enzymes was also studied by filtration.

Date of Award	2010
Original language	English