Study of the Amylolytic Activity of Thermophilic Bacteria Isolated from an Algerian Hot Spring (Azzaba, Skikda)

Abstract

Thermostable amylases are among the most widely used and desirable enzymes in the food industry. Indeed, they guarantee faster reactions at high temperatures, enhanced substrate solubility and reduced microbial contamination and cooling costs. The objective of this work is to study the amylase activity of three strains of aerobic thermophilic bacteria isolated from the hot spring of Hammam Salhine, located in the wilaya of Skikda, Algeria. The three extracellular amylase-producing strains were subjected to the quantification of amylase activity. They presented medium to high activity, with significantly the best production for the AS1 strain with an activity of 10.62 ± 1.289 U (p > 0.05). Monitoring the kinetics of AS1 amylase activity reveals that the maximum enzymatic activity was reached after 52 h with a value of 53.665 ± 2.534 U. The maximum growth was reached after 54 h of fermentation at an OD of 0.865 ± 0.081 at 600 nm. The study of the effect of the variation in physicochemical parameters on the activity of AS1 amylase extract shows that the enzymatic activity was maximal at a temperature of 100 °C, a pH of 8.0 and in the absence of NaCl. The amylase extract of this strain showed significant thermostability at 100 °C.

Keywords

• bacteria
• thermophiles
• amylase activity
• enzyme assay
• thermostability