Enzymatic potential for decomposition of detrital biopolymers in sediments from Kiel Bay

Abstract

Abstract Enzymatic activities involved in the solubilization of particulate organic matter (POM) were determined in the surface samples from coastal sediments of Kiel Bay (Baltic Sea). For this purpose dye release assays were developed and standardized to measure the enzymatic conversion of dye-labelled particulate protein, cellulose, chitin, agar, and algal cell walls to soluble fragments. On the average, about half of the total POM-solubilizing activities were proteolytic. These were reduced when oxygen availability or Eh became limiting. Seasonal and spatial distribution patterns showed opposite trends for protein- and polysaccharide-solubilizing enzymes (most clearly for cellulase). Among the polysaccharases investigated, agarase activities were consistently predominant. During periods of intensive advection of macroalgae in winter they reached even the level of proteolytic activities. Intermediate levels of activity were noted for stained cell walls as a mixed natural substrate. Seasonal changes of t...