Arnosti, C. University of North Carolina,

Biofilms, complex carbohydrate-containing matrices, are ubiquitous features of sediments and surfaces in marine systems. They host microbial communities whose metabolic capabilities are still largely unexplored. The ability to use macromolecular substrates, in biofilms as elsewhere in marine environments, is closely linked to the capabilities of at least some members of a community to produce the extracellular enzymes required to hydrolyze organic macromolecules to sizes small enough to be transported across microbial membranes. To date, a limited number of low molecular-weight proxies have been used to characterize the enzymatic capabilities of biofilm microbial communities. A new approach, employing fluorescently-labeled polysaccharides, has been developed to investigate extracellular enzymatic activities of microbial communities. This work initially focused on investigating hydrolysis rates of uncharged polysaccharides in sediments. The current emphasis is on development of a new array of complex polysaccharide substrates which can be used to measure hydrolysis rates and substrate specificities of enzymes likely to be important in biofilms and other complex carbohydrate-containing matrices such as TEP. Investigations to date have demonstrated that potential hydrolysis rates vary significantly among substrates, and between environments. Future work is aimed at determining spatial locations, as well as rates and specificities, of extracellular enzymatic hydrolysis.
Day: Monday, Feb. 1
Time: 04:15 - 04:30pm
Location: Sweeney Center
Code: SS17MO0415S