Soil Amylase

Abstract

Amylases are widely distributed in soils and have a wide range of activities (Ladd and Butler 1972) and properties (Ladd and Butler 1969). Starch is a major carbon compound within most plant tissues and increases during active photosynthesis and decreases as it is enzymatically converted into sugars. Amylase catalyzes the hydrolytic depolymerization of polysaccharides in soil (Tu and Miles 1976). Starch-hydrolyzing enzymes are usually extracellular and inducible, but their activity depends on the type of substrate (Alexander 1977). Soil amylase is responsible for the major breakdown of complex polysaccharides including starch to a readily available form of glucose (Singaram and Kamalakumari 2000). Production of these extracellular enzymes from microbes during litter degradation may be influenced by temperature, moisture, pH, and substrate involvement (Linkins et al. 1984; Sinsabaugh and Linkins 1987). Amylase activity was significantly correlated with fungal and bacterial populations and moisture content of litter (Joshi et al. 1993). Changes in amylase activity during litter decomposition were attributed to changes in microbial populations (Ross and Roberts 1973). Increased amylase activity was observed when soil was treated with insecticides and pesticides (Tu 1982), effluents released from pulp and paper mills (Kannan and Oblisami 1990b), cotton ginning mills (Narasimha 1997), and pressmud plus paper mill effluents (Chinnaiah et al. 2002). By contrast, amylase activity was reduced when soil was treated with imidacloprid (Tu 1995), dimethoate (Mandic et al. 1997), and chlorothalonil (Singh et al. 2002).