Microbial Parameters as a Practical Tool for the Functional Characterization and Ecological Status Assessment of Transitional Areas

Enzymatic biodegradation of high molecular weight polymers in the sediment–water interface in the coastal river estuary

“…As a key process in microbial ecology, extracellular enzymatic activity has received considerable attention (Caruso, ; Tiquia, ). According to Fabiano and Danovaro () and Zheng et al (), the studies on extracellular enzymatic activity are helpful in better understanding of the role of these biocatalysts in organic matter and energy cycles in water environment.…”

“…Apart from lipases, also aminopeptidase showed a high potential level of activity in the SWI of the coastal river estuary in Ustka. According to Hoppe, Arnosti, and Herndel () and Caruso (), aminopeptidase is a common extracellular enzyme in water ecosystems. This enzyme hydrolyses proteins and polypeptides, which in water basins constitute 35–55% of dry mass of organic matter, into peptides and amino acids (Ainsworth & Goulder, ; Davey, Kirby, Turley, Weightman, & Fry, ).…”

“…The level of phosphatase activity is usually regulated by the phosphate supply, as this activity increases with decreasing phosphate concentration (Hoppe, ; Yamada et al, ). Therefore, high phosphatase activity in heavily eutrophicated SWI of the studied coastal river estuary probably results from the fact that, in eutrophic environments, this hydrolase is produced in great amounts when inorganic P becomes limited (Caruso, ; Santos et al, ).…”

“…A large fraction (about 95%) of biomolecules accumulated in water basins are heterogeneous matrix composed of large polymers of high molecular (HMW > 10 kDa) weight compounds (Caruso, ; Celussi & Del Negro, ; Raghul & Bhat, ), out of which the most representative are proteins, polysaccharides, lipids, starch, pectin, cellulose, chitin, nucleic acids, and lignin (Allison, Chao, Farrara, Hatosy, & Martiny, ; Caruso, ). According to Turley (), the bacteria inhabiting the SWI have been recognized as the major consumers and transformers of these macromolecules.…”

“…These are mainly aquatic aerobic heterotrophic bacteria that hydrolyse high molecular weight polymers using extracellular enzymes, that is, exohydrolases and endohydrolases, which cleave C–O and C–N bonds that link monomers (Cunha et al, ; Gallizia, Vezzulli, & Fabiano, ). Bacteria due to a dynamic induction of their enzymatic systems are capable of very fast adapting their metabolic profiles to autochthonous and allochthonous organic matter inputs into the water environment (Caruso, ; Divya et al, ).…”