scholarly journals Influence of water availability and temperature on estimates of microbial extracellular enzyme activity

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10994
Author(s):  
Enrique J. Gomez ◽  
Jose A. Delgado ◽  
Juan M. Gonzalez
Keyword(s):  
Enzyme Activity ◽  
Water Availability ◽  
Extracellular Enzymes ◽  
Extracellular Enzyme ◽  
High Water ◽  
Extracellular Enzyme Activity ◽  
Soil Conditions ◽  
Natural Soil ◽  
Influence Of Water ◽  
Complex Polymers

Soils are highly heterogeneous and support highly diverse microbial communities. Microbial extracellular enzymes breakdown complex polymers into small assimilable molecules representing the limiting step of soil organic matter mineralization. This process occurs on to soil particles although currently it is typically estimated in laboratory aqueous solutions. Herein, estimates of microbial extracellular enzyme activity were obtained over a broad range of temperatures and water availabilities frequently observed at soil upper layers. A Pseudomonas strain presented optimum extracellular enzyme activities at high water activity whereas a desiccation resistant bacterium (Deinococcus) and a soil thermophilic isolate (Parageobacillus) showed optimum extracellular enzyme activity under dried (i.e., water activities ranging 0.5–0.8) rather that wet conditions. Different unamended soils presented a distinctive response of extracellular enzyme activity as a function of temperature and water availability. This study presents a procedure to obtain realistic estimates of microbial extracellular enzyme activity under natural soil conditions of extreme water availability and temperature. Improving estimates of microbial extracellular enzyme activity contribute to better understand the role of microorganisms in soils.

scholarly journals Purification efficiency of eight aquatic plant species in an artificial floating island system in relation to extracellular enzyme activity and microbial community

2021 ◽  
Vol 27 (6) ◽  
pp. 210443-0
Author(s):  
Lei Li ◽  
You Feng ◽  
Jinye Li ◽  
Qing Li ◽  
Ting Liu ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Microbial Community ◽  
Plant Species ◽  
Aquatic Plant ◽  
Extracellular Enzymes ◽  
Extracellular Enzyme ◽  
Extracellular Enzyme Activity ◽  
Purification Efficiency ◽  
Floating Island ◽  
Island System

The floating island system exploits the combination of aquatic plants, microorganisms, and extracellular enzymes to purify wastewater. We investigated the purification efficiency of eight aquatic plant species cultured in wastewater. The relationships of plant purification capacity with extracellular enzyme activity and microbial community were analyzed to explore the crucial factors that affect the plant purification capacity and the mechanism of pollutants removal in different plant systems. Three plant species, namely Oenanthe javanica, Thalia dealbata, and lris pseudacorus, were most effective for purification of ammonium-nitrogen (NH4<sup>+</sup>-N), total phosphate (TP), and chemical oxygen demand (COD) with maximum efficiencies of 76.09, 85.87, and 89.10%, respectively. Urease, alkaline phosphatase (AP), and β-glucosidase activities were significantly and positively correlated with root system development (P < 0.05). Activities of urease and AP were positively correlated with NH4<sup>+</sup>-N and TP removal, respectively. The magnitude of urease and AP activity was generally consistent with the plant’s capacity to remove NH4<sup>+</sup>-N and TP. β-Glucosidase activity and COD removal were not significantly correlated. The dominant microbial phylum in each species treatment was Proteobacteria. Alphaproteobacteria and Bacteroidia showed > 1% relative abundance and greater involvement in degradation of pollutants in the experimental system.

scholarly journals Distribusi Bakteri Penghasil Enzim Ekstraseluler Pada Saluran Pencernaan Lobster Mutiara (Panulirus ornatus)

2019 ◽  
Vol 5 (2) ◽  
pp. 71
Author(s):  
Fatur Rahman ◽  
Ismiati Ismiati ◽  
Arbai Nurhasanah
Keyword(s):  
Enzyme Activity ◽  
Digestive Tract ◽  
Extracellular Enzymes ◽  
Extracellular Enzyme ◽  
Extracellular Enzyme Activity ◽  
Bacterial Isolates ◽  
Clear Zone ◽  
Zone Diameter ◽  
Protease Enzyme ◽  
Proteolytic Bacteria

The activity of the digestive function of animals is influenced by the secretion of extracellular enzymes from bacteria in the digestive tract. This study aims to evaluate the distribution of bacteria producing protease enzyme, amylase and lipase from the digestive tract of pearl lobster, Panulirus ornatus. Bacterial isolates that have extracellular enzyme activity are based on their ability to form clear zones in the test media. The results showed that of 51 bacterial isolates from the digestive tract of P. ornatus, proteolytic bacteria were 27.45%, amylolytic bacteria were 23.53% and lipolytic bacteria were 21.77%. Based on bacterial dominance in the gastrointestinal segment, namely the cardiac, piloric and intestinal sections, it was dominated by amylolytic bacteria at 33.33%, proteolytic at 37.50% and lipolytic at 29.41%. The activity of proteolytic, amylolytic and lipolytic bacteria based on the highest clear zone diameter was achieved respectively by SP5 isolates of 12 mm, SK10 isolates of 21 mm and SU15 isolates of 20 mm. The three bacterial isolates were potential as probiotic aquacultur candidates

scholarly journals In vitro conversion of proapoprotein A-I to apoprotein A-I. Partial characterization of an extracellular enzyme activity.

1983 ◽  
Vol 258 (19) ◽  
pp. 11430-11433 ◽  
Author(s):  
C Edelstein ◽  
J I Gordon ◽  
K Toscas ◽  
H F Sims ◽  
A W Strauss ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Extracellular Enzyme ◽  
Extracellular Enzyme Activity ◽  
Partial Characterization

Temperature Sensitivity of Intracellular and Extracellular Soil Enzyme Activities

2021 ◽  
Author(s):  
Adetunji Alex Adekanmbi ◽  
Laurence Dale ◽  
Liz Shaw ◽  
Tom Sizmur
Keyword(s):  
Enzyme Activity ◽  
Soil Temperature ◽  
Temperature Sensitivity ◽  
Extracellular Enzymes ◽  
Extracellular Enzyme ◽  
Daily Maximum ◽  
Temperature Sensitive ◽  
Intracellular Enzyme ◽  
Temperature Changes ◽  
Som Decomposition

&lt;p&gt;Predicting the pattern of soil organic matter (SOM) decomposition as a feedback to climate change, via release of CO&lt;sub&gt;2&lt;/sub&gt;, is extremely complex and has received much attention. However, investigations often do not differentiate between the extracellular and intracellular processes involved and work is needed to identify their relative temperature sensitivities. Samples were collected from a grassland soil at Sonning, UK with average daily maximum and minimum soil temperature of 15 &amp;#176;C and 5 &amp;#176;C. We measured potential activities of &amp;#946;-glucosidase (BG) and chitinase (NAG) (extracellular enzymes) and glucose-induced CO&lt;sub&gt;2 &lt;/sub&gt;respiration (intracellular enzymes) at a range of assay temperatures (5 &amp;#176;C, 15 &amp;#176;C, 26 &amp;#176;C, 37&lt;sup&gt; &amp;#160;&lt;/sup&gt;&amp;#176;C, and 45 &amp;#176;C). The temperature coefficient Q&lt;sub&gt;10&lt;/sub&gt; (the increase in enzyme activity that occurs after a 10 &amp;#176;C increase in soil temperature) was calculated to assess the temperature sensitivity of intracellular and extracellular enzymes activities. Between 5 &amp;#176;C and 15 &amp;#176;C intracellular and extracellular enzyme activities had equal temperature sensitivity, but between 15 &amp;#176;C and 26&amp;#176;C intracellular enzyme activity was more temperature sensitive than extracellular enzyme activity and between 26 &amp;#176;C and 37 &amp;#176;C extracellular enzyme activity was more temperature sensitive than intracellular enzyme activity. This result implies that extracellular depolymerisation of higher molecular weight organic compounds is more sensitive to temperature changes at higher temperatures (e.g. changes to daily maximum summer temperature) but the intracellular respiration of the generated monomers is more sensitive to temperature changes at moderate temperatures (e.g. changes to daily mean summer temperature). We therefore conclude that the extracellular and intracellular steps of SOM mineralisation are not equally sensitive to changes in soil temperature. The finding is important because we have observed greater increases in average daily minimum temperatures than average daily mean or maximum temperatures due to increased cloud cover and sulphate aerosol emission. Accounting for this asymmetrical global warming may reduce the importance of extracellular depolymerisation and increase the importance of intracellular catalytic activities as the rate limiting step of SOM decomposition.&lt;/p&gt;

Source of organic detritus and bivalve biomass influences nitrogen cycling and extracellular enzyme activity in estuary sediments

2019 ◽  
Vol 145 (3) ◽  
pp. 315-335 ◽  
Author(s):  
Josie Crawshaw ◽  
Theresa O’Meara ◽  
Candida Savage ◽  
Blair Thomson ◽  
Federico Baltar ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Nitrogen Cycling ◽  
Extracellular Enzyme ◽  
Extracellular Enzyme Activity ◽  
Organic Detritus
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