Extracellular enzyme-clay mineral complexes: Enzyme adsorption, alteration of enzyme activity, and protection from photodegradation

  title={Extracellular enzyme-clay mineral complexes: Enzyme adsorption, alteration of enzyme activity, and protection from photodegradation},
  author={Todd E. Tietjen and Robert G. Wetzel},
  journal={Aquatic Ecology},
Enzymes released extracellularly by micro-organisms have major functions in nutrient acquisition and organic matter degradation. Clay particles, common in many surface waters, can modify enzyme activity. Clay minerals are known to form aggregates with organic molecules, and the formation of enzyme-clay complexes could alter the level of activity. Montmorillonite clay and clay extracted from Elledge Lake (Tuscaloosa, Alabama) basin soil were combined with alkaline phosphatase, glucosidase… 
Persistent Activities of Extracellular Enzymes Adsorbed to Soil Minerals
It is shown that a limited availability of sorption sites is important for high specific activity and persistence of the enzymes, and that the soil mineral phase supports microorganisms in less-sorptive environments by saving energy on enzyme production.
The results revealed that the affinity to the substrate and the maximum reaction velocity of ALP decreased upon adsorption on the fibrous clay minerals, while the inhibitory effects of Cd on both the free and adsorbed ALP activities were competitive in nature.
Control of Soil Extracellular Enzyme Activities by Clay Minerals—Perspectives on Microbial Responses
Knowledge of how interactions of clay minerals and extracellular enzymes (EEs) influence organic matter turnover in soils are still under discussion. We studied the effect of different
Effect of arsenate contamination on free, immobilized and soil alkaline phosphatases: activity, kinetics and thermodynamics
The results suggest that the type of arsenate inhibition on free soluble ALP was competitive inhibition, whereas for immobilized and soil ALPs, the inhibition was competitive or mixed inhibition depending on the mineral or soil property.
Soil minerals and humic acids alter enzyme stability: implications for ecosystem processes
In most ecosystems, the degradation of complex organic material depends on extracellular enzymes produced by microbes. These enzymes can exist in bound or free form within the soil, but the dynamics


Inhibition of phosphatase activity by dissolved humic substances and hydrolytic reactivation by natural ultraviolet light
The data support a previously suggested hypothesis that phosphatases and other enzymes in aquatic ecosystems can complex with humic substances that dominate the DOM pool.
Hydrolytic extracellular enzyme activity in heterotrophic biofilms from two contrasting streams
The oligotrophic biofilm was found to contain about twice as much extracellular esterase activity as the more eutrophic River Clywedog biofilm, although these activities also fluctuated during the colonization period.
Influence of Algal Biomass on Extracellular Enzyme Activity in River Biofilms
The relevance of algal biomass on the heterotrophic ability of biofilms may be related to the physical proximity between the two, but also to the high proportion of polymeric carbohydrates included in algal exudates and lysis products, whose use is enzyme-mediated.
Seasonal and Spatial Distribution of Extracellular Enzymatic Activities and Microbial Incorporation of Dissolved Organic Substrates in Marine Sediments
  • L. Meyer-Reil
  • Environmental Science
    Applied and environmental microbiology
  • 1987
The high microbial incorporation of leucine and thymidine during winter demonstrated that the nutrient supply rather than temperature is the dominating factor determining microbial production.
'Clay hutches': a novel interaction between bacteria and clay minerals.
The formation of clay hutches by bacteria would seem to merit further investigation, particularly regarding their roles in bacterial processes in soil and in geological processes, and the interesting possibilities that the 'clay hutches' may represent a 'soil microhabitat', a 'minimal nutritional sphere' and an 'effective survival unit' for autochthonous bacteria are noted.
Use of Fluorogenic Model Substrates for Extracellular Enzyme Activity (EEA) Measurement of Bacteria
The quantitative estimates of total bacterial extracellular enzyme activity are completed by rapid and sensitive tests for the detection of enzymatic properties of bacterial isolates, based on the application of fluorogenic model substrates.
Heavy Metal Adsorption by Functionalized Clays
Organic ligands containing the thiol (−SH) metal-chelating functionality were either grafted to the external surface silanol groups of sepiolite or introduced in the interlayers of montmorillonite,
Seasonal variation of epiphytic extracellular enzyme activity on two freshwater plants, Phragmites australis and Elodea canadensis
Values of epiphytic enzyme activity relative to activity in pond water were substantial enough to suggest that, at well vegetated sites, epiphanic enzyme activity should make up an appreciable proportion of whole-pond extracellular enzyme activity.