Enrique J Gomez1, Jose A Delgado1, Juan M Gonzalez1. 1. Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, IRNAS-CSIC, Sevilla, Spain.
Abstract
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.
Soils are highly heterogenpan>eous and support highly diverse microbial communities. Microbial extracellular enpan>zymes breakdownn class="Chemical">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.
Authors: Joel A Biederman; Russell L Scott; Michael L Goulden; Rodrigo Vargas; Marcy E Litvak; Thomas E Kolb; Enrico A Yepez; Walter C Oechel; Peter D Blanken; Tom W Bell; Jaime Garatuza-Payan; Gregory E Maurer; Sabina Dore; Sean P Burns Journal: Glob Chang Biol Date: 2016-02-15 Impact factor: 10.863
Authors: Krzysztof Kolman; Marcin M Makowski; Ali A Golriz; Michael Kappl; Jacek Pigłowski; Hans-Jürgen Butt; Adam Kiersnowski Journal: Langmuir Date: 2014-09-26 Impact factor: 3.882