Abstract

GUTIERREZ R., Viviana; PINZON E., Ángela; CASAS, Jaime  and  MARTINEZ, María Mercedes. Determination of cellulolytic activity of soil from Stevia rebaudiana Bertoni crops. Agron. colomb. [online]. 2008, vol.26, n.3, pp.497-504. ISSN 0120-9965.

In this study celullolytic activity was determined in soil using a fluorogenic technique, which utilizes 4-methylumbelliferil B-glucose (MUF) as substrate, and was compared with the quantitative technique of Somogyi Nelson (SN). Sediment control was handled as a positive method of MUF, as this technique was standardized previously in this matrix. Soil sampling was done in Puerto López, Meta, in Stevia rebaudiana Bertoni crops using a simple random sampling. Sediments were collected in La Conejera wetland located in Suba, Bogotá. Three treatments were done to both matrixes: T1: Matrix (control); T2: Matrix + crude enzymatic extract (2.34 UC); T3: Matrix + Streptomyces sp (59x103 spores/mL). To obtain the crude enzymatic extract used in T2 an isolation of the celulloytic microogranisms was done with greater activity in carboximethylcellulose (CMC 1%) from soil samples for its subsequent fermentation and extraction of enzyme extract. Incubation of the matrix in three treatments was done at room temperature during 60 days where tests were performed every 15 days in order to analyze enzymatic activity by the established methods (MUF and SN). Humidity was maintained at 4.6%. No evidence of differential effects in the enzymatic activity with any of the treatments was found. Also, there was no statistical correlation between the methods (<16%). Thus, we propose the fluorogenic technique as a viable and reliable methodology to determinate cellulolytic activity because of its high specificity, faster assembly as well as its easy manipulation, precision and repeatability. Nevertheless the SN technique has not been ruled out for future studies.

Keywords : B-glucosidase; celullases; 4-methylumbelliferil B-glucose; Somogyi Nelson; soil quality.

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