Enzyme Characterization of Endophytic Actinobacteria Isolated from Tomato Plants

Endophytic actinobacteria produce active metabolites, protecting plant tissues against stress. They compounds are widely used in human and veterinary pharmaceutics and agriculture, and of several enzymes with biotechnological potential. The present study characterizes the enzymatic production of endophytic actinobacteria colonizing tomato plants. Twenty-three actinobacteria isolates were tested for the detection of amylase, pectinase, cellulose, lipase, esterase, caseinase, gelatinase and catalase, at three temperatures (25 ̊C, 28 ̊C and 30 ̊C) for 7 days. Substrate hydrolysis and enzymatic index (EI) were determined. The results showed that mean EI of all actinobacteria isolates was between 0.8 and 7.1. Although 30 ̊C was the temperature at which the highest number of isolates presented enzymatic activity, it was at 25 ̊C that amylase, pectinase, lipase and esterase activity reached the highest mean EI. Catalase was produced by all actinobacteria, while lipase, esterase and pectinase activity was observed for at least 20 isolates, regardless the incubation temperature. However, the highest number of isolates able to hydrolyze gelatin and cellulose (8) was observed when growth was carried out at 30 ̊C. The highest EI means were observed for the hydrolysis of lipases, while the lowest values were seen for the hydrolysis of cellulose.