Significance of Extracellular Enzymes for Organic Matter Degradation and Nutrient Regeneration in Small Streams

1991 ◽  
pp. 270-285 ◽  
Author(s):  
Jürgen Marxsen ◽  
Karl-Paul Witzei
Keyword(s):  
Organic Matter ◽  
Extracellular Enzymes ◽  
Organic Matter Degradation ◽  
Nutrient Regeneration ◽  
Small Streams

scholarly journals Enhancement of Cellulose Rich Organic Matter Degradation by Inoculation with Streptomyces sp. Strains

2021 ◽  
Vol 26 (02) ◽  
pp. 257-262
Author(s):  
Simonida Djuri
Keyword(s):  
Organic Matter ◽  
Extracellular Enzymes ◽  
Biochemical Characterization ◽  
Cellulose Degradation ◽  
Organic Matter Degradation ◽  
Incubation Experiment ◽  
Cellulose Production ◽  
Streptomyces Sp ◽  
Streptomyces Spp

Microbial degradation of organic matter is a vital part of carbon cycle in nature. Actinobacteria play an important role in the decomposition of cellulose rich organic matter (CROM). Streptomyces spp. are abundant in soil, produce various secondary metabolites and secrete extracellular enzymes. The aim of this research was to isolate and select Streptomyces strains with the best cellulose degradation abilities. Out of total 32 actinobacteria isolates, four Streptomyces strains (CA1, CA10, PA2 and PA7) were subjected to morphological, physiological, biochemical characterization and molecular identification. CROM degradation potential of the strains was investigated on straw and beech briquettes as well as on legume based substrate in in vitro condition. Streptomyces strains CA1 and CA10 showed the best cellulose production and starch hydrolysis abilities, followed by strains PA2 and PA7. Strain CA1 was also positive to production of pectinase enzymes. Streptomyces zaomyceticus CA1 and S. tanashiensis CA10 were used as inoculants, which degraded the raw cellulose from 38.38 to 81.69% in the investigated substrates (straw, beech, legume), during a 30-day incubation experiment. CROM inoculation with the selected Streptomyces strains improved and accelerated its degradation in controlled conditions. © 2021 Friends Science Publishers

scholarly journals Cell-free extracellular enzymatic activity is linked to seasonal temperature changes: a case study in the Baltic Sea

2016 ◽  
Vol 13 (9) ◽  
pp. 2815-2821 ◽  
Author(s):  
Federico Baltar ◽  
Catherine Legrand ◽  
Jarone Pinhassi
Keyword(s):  
Organic Matter ◽  
Baltic Sea ◽  
Extracellular Enzymes ◽  
Seasonal Pattern ◽  
Critical Factor ◽  
Hydrolytic Activity ◽  
Seasonal Temperature ◽  
The Baltic Sea ◽  
The Baltic ◽  
Hydrolysis Of

Abstract. Extracellular enzymatic activities (EEAs) are a crucial step in the degradation of organic matter. Dissolved (cell-free) extracellular enzymes in seawater can make up a significant contribution of the bulk EEA. However, the factors controlling the proportion of dissolved EEA in the marine environment remain unknown. Here we studied the seasonal changes in the proportion of dissolved relative to total EEA (of alkaline phosphatase (APase), β-glucosidase (BGase), and leucine aminopeptidase (LAPase)), in the Baltic Sea for 18 months. The proportion of dissolved EEA ranged between 37 and 100, 0 and 100, and 34 and 100 % for APase, BGase, and LAPase, respectively. A consistent seasonal pattern in the proportion of dissolved EEA was found among all the studied enzymes, with values up to 100 % during winter and  <  40 % during summer. A significant negative relation was found between the proportion of dissolved EEA and temperature, indicating that temperature might be a critical factor controlling the proportion of dissolved relative to total EEA in marine environments. Our results suggest a strong decoupling of hydrolysis rates from microbial dynamics in cold waters. This implies that under cold conditions, cell-free enzymes can contribute to substrate availability at large distances from the producing cell, increasing the dissociation between the hydrolysis of organic compounds and the actual microbes producing the enzymes. This might also suggest a potential effect of global warming on the hydrolysis of organic matter via a reduction of the contribution of cell-free enzymes to the bulk hydrolytic activity.

scholarly journals Timescales for the development of methanogenesis and free gas layers in recently-deposited sediments of Arkona Basin (Baltic Sea)

2012 ◽  
Vol 9 (5) ◽  
pp. 1915-1933 ◽  
Author(s):  
J. M. Mogollón ◽  
A. W. Dale ◽  
H. Fossing ◽  
P. Regnier
Keyword(s):  
Organic Matter ◽  
Baltic Sea ◽  
Reactive Transport ◽  
Reaction Pathway ◽  
Organic Matter Degradation ◽  
Muddy Sediment ◽  
Transport Models ◽  
Methane Gas ◽  
Geochemical Profiles ◽  
Arkona Basin

Abstract. Arkona Basin (southwestern Baltic Sea) is a seasonally-hypoxic basin characterized by the presence of free methane gas in its youngest organic-rich muddy stratum. Through the use of reactive transport models, this study tracks the development of the methane geochemistry in Arkona Basin as this muddy sediment became deposited during the last 8 kyr. Four cores are modeled each pertaining to a unique geochemical scenario according to their respective contemporary geochemical profiles. Ultimately the thickness of the muddy sediment and the flux of particulate organic carbon are crucial in determining the advent of both methanogenesis and free methane gas, the timescales over which methanogenesis takes over as a dominant reaction pathway for organic matter degradation, and the timescales required for free methane gas to form.

Beneficial effect of mixture of additives amendment on enzymatic activities, organic matter degradation and humification during biosolids co-composting

2018 ◽  
Vol 247 ◽  
pp. 138-146 ◽  
Author(s):  
Mukesh Kumar Awasthi ◽  
Quan Wang ◽  
Hongyu Chen ◽  
Sanjeev Kumar Awasthi ◽  
Meijing Wang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Beneficial Effect ◽  
Enzymatic Activities ◽  
Organic Matter Degradation

scholarly journals Temperature and UV light affect the activity of marine cell-free enzymes

2017 ◽  
Vol 14 (17) ◽  
pp. 3971-3977 ◽  
Author(s):  
Blair Thomson ◽  
Christopher David Hepburn ◽  
Miles Lamare ◽  
Federico Baltar
Keyword(s):  
Organic Matter ◽  
Extracellular Enzymes ◽  
Elevated Temperatures ◽  
Uv Light ◽  
Control Mechanisms ◽  
Potential Control ◽  
Control Factors ◽  
Rate Limiting Step ◽  
Ocean Environment ◽  
First Time

Abstract. Microbial extracellular enzymatic activity (EEA) is the rate-limiting step in the degradation of organic matter in the oceans. These extracellular enzymes exist in two forms: cell-bound, which are attached to the microbial cell wall, and cell-free, which are completely free of the cell. Contrary to previous understanding, cell-free extracellular enzymes make up a substantial proportion of the total marine EEA. Little is known about these abundant cell-free enzymes, including what factors control their activity once they are away from their sites (cells). Experiments were run to assess how cell-free enzymes (excluding microbes) respond to ultraviolet radiation (UVR) and temperature manipulations, previously suggested as potential control factors for these enzymes. The experiments were done with New Zealand coastal waters and the enzymes studied were alkaline phosphatase (APase), β-glucosidase, (BGase), and leucine aminopeptidase (LAPase). Environmentally relevant UVR (i.e. in situ UVR levels measured at our site) reduced cell-free enzyme activities by up to 87 % when compared to controls, likely a consequence of photodegradation. This effect of UVR on cell-free enzymes differed depending on the UVR fraction. Ambient levels of UV radiation were shown to reduce the activity of cell-free enzymes for the first time. Elevated temperatures (15 °C) increased the activity of cell-free enzymes by up to 53 % when compared to controls (10 °C), likely by enhancing the catalytic activity of the enzymes. Our results suggest the importance of both UVR and temperature as control mechanisms for cell-free enzymes. Given the projected warming ocean environment and the variable UVR light regime, it is possible that there could be major changes in the cell-free EEA and in the enzymes contribution to organic matter remineralization in the future.

scholarly journals Response of <i>Nodularia spumigena</i> to <i>p</i>CO<sub>2</sub> – Part 2: Exudation and extracellular enzyme activities

2013 ◽  
Vol 10 (1) ◽  
pp. 567-582 ◽  
Author(s):  
S. Endres ◽  
J. Unger ◽  
N. Wannicke ◽  
M. Nausch ◽  
M. Voss ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Organic Matter ◽  
Enzyme Activities ◽  
Extracellular Enzymes ◽  
Extracellular Enzyme ◽  
High Pco2 ◽  
Nodularia Spumigena ◽  
Extracellular Enzyme Activities ◽  
Pco2 Treatment ◽  
Co2 Concentrations

Abstract. The filamentous and diazotrophic cyanobacterium Nodularia spumigena plays a major role in the productivity of the Baltic Sea as it forms extensive blooms regularly. Under phosphorus limiting conditions Nodularia spumigena have a high enzyme affinity for dissolved organic phosphorus (DOP) by production and release of alkaline phosphatase. Additionally, they are able to degrade proteinaceous compounds by expressing the extracellular enzyme leucine aminopeptidase. As atmospheric CO2 concentrations are increasing, we expect marine phytoplankton to experience changes in several environmental parameters, including pH, temperature, and nutrient availability. The aim of this study was to investigate the combined effect of CO2-induced changes in seawater carbonate chemistry and of phosphate deficiency on the exudation of organic matter, and its subsequent recycling by extracellular enzymes in a Nodularia spumigena culture. Batch cultures of Nodularia spumigena were grown for 15 days under aeration with low (180 μatm), medium (380 μatm), and high (780 μatm) CO2 concentrations. Obtained pCO2 levels in the treatments were on median 315, 353, and 548 μatm CO2, respectively. Extracellular enzyme activities as well as changes in organic and inorganic compound concentrations were monitored. CO2 treatment–related effects were identified for cyanobacterial growth, which in turn influenced the concentration of mucinous substances and the recycling of organic matter by extracellular enzymes. Biomass production was increased by 56.5% and 90.7% in the medium and high pCO2 treatment, respectively, compared to the low pCO2 treatment. In total, significantly more mucinous substances accumulated in the high pCO2 treatment, reaching 363 μg Xeq L−1 compared to 269 μg Xeq L−1 in the low pCO2 treatment. However, cell-specific rates did not change. After phosphate depletion, the acquisition of P from DOP by alkaline phosphatase was significantly enhanced. Alkaline phosphatase activities were increased by factor 1.64 and 2.25, respectively, in the medium and high compared to the low pCO2 treatment. We hypothesise from our results that Nodularia spumigena can grow faster under elevated pCO2 by enhancing the recycling of organic matter to acquire nutrients.

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