Effect of temperature and ph on amylolytic activities of bacillus atrophaeus and paenibacillus polymixa isolated from amazonian soils

The "Pro-Alcohol" program in Brazil is based on the use of sugarcane and, since the harvest is carried out once a year, there is a period of inactivity between harvests. As a result, several mills began to use in the off-season, starch producing species for alcohol production. In order to use these plant species, it is necessary the use of α-amylases. The search for thermotolerant amylases in bacteria isolated from Amazonian soils is an important strategy to reduce and even stop importing these enzymes. For this purpose, tests were conducted in solid and liquid media with two previously selected bacteria (Paenibacillus polymyxa ITAAM 10M and Bacillus atrophaeus ITAA 23M) using a 1% starch solution to detect starch degradation index. Then the enzymatic complexes of these bacteria were tested at different temperatures and pHs. Both bacteria enzymatic complexes were influenced by temperatures and pHs of the cultivation medium. The amylolysis indices of Bacillus atrophaeus ITAAM 23M and Paenibacillus polymyxa ITAAM 10M were respectively 1.5 and 1.2. The amylases of both bacteria differed in their chemical characteristics and were most active at 100 °C. The highest amylolytic activity demonstrated by amylases was 1.37 U.mL-1 and 1.18 U.mL-1 respectively for P. polymyxa and B. atrophaeus.