P59: Enzyme production by microorganisms isolated from high altitude lands

Thermophilic microorganisms are usually used to produce extracellular industrial enzymes such as amylases, xylanases, proteases, cellulases. The aim of this work was the screening of hydrolytic enzyme production of 22 isolated strains from high altitude lands from Puna Argentina and Brasilia forest. Each strain was inoculated as a single colony in agar plates with soluble starch, skim milk, Birchwood xylane and carboximethylcellulose as substrates. Hydrolysis halos were measured and expressed as hydrolysis index: colony diameter/(colony + halo diameter). Three bacteria strains which presented higher hydrolysis ability at 45ºC than at 37ºC were selected and identified as Bacillus licheniformis (L2 strain), Bacillus amyloliquefaciens (L3 strain) and Alicyclobacillus acidocaldarius (L5 strain). Total proteins (Bradford 1976) and amylase activity (UA/ml) (Amilokit, Wiener) were determined in batch cultures at 45ºC, pH 7.0 and 300rpm in a rotary shaker. Maximal amylase activity achieved were 9.65, 9.07 and 8.37 UA/ml for B. licheniformis L2, B. amyloliquefaciens L3 and A. acidocaldarius L5 respectively. Thermal stability of amylase in the supernatant culture was studied in a range of  45 to 65ºC during 15min. Amylase activity of the three strains remained between 89 to 99% of the control value ( without heating) depending on the temperature used during the thermal treatment. These results showed that this bacteria can be used to produce extracellular enzymes to be used in industrial processes whenever chemical reactions must be made at high temperatures.