Abstract

ANDRADE, Marcela Vicente Vieira de; DELATORRE, Andréia Boechat; LADEIRA, Silvania Alves  and  MARTINS, Meire Lelis Leal. Production and partial characterization of alkaline polygalacturonase secreted by thermophilic Bacillus sp. SMIA-2 under submerged culture using pectin and corn steep liquor. Ciênc. Tecnol. Aliment. [online]. 2011, vol.31, n.1, pp. 204-208. ISSN 0101-2061.  http://dx.doi.org/10.1590/S0101-20612011000100031.

Polygalacturonase production by the thermophilic Bacillus sp. SMIA-2 cultivated in liquid cultures containing 0.5% (w/v) apple pectin and supplemented with 0.3% (w/v) corn steep liquor, reached its maximum after 36 hours with levels of 39 U.mL^-1. The increase in apple pectin and corn steep liquor concentrations in the medium from 0.5 and 0.3%, respectively, to 0.65%, markedly affected the production of polygalacturonase, whose activity increased four times, reaching a maximum of 150.3 U.mL^-1. Studies on polygalacturonase characterization revealed that the optimum temperature of this enzyme was between 60-70 °C. Thermostability profile indicated that the enzyme retained about 82 and 63% of its activity at 60 and 70 °C, respectively, after 2 hours of incubation. The optimum pH of the enzyme was found to be 10.0. After incubation of crude enzyme solution at room temperature for 2 hours at pH 8.0, a decrease of about 29% on its original activity was observed. At pH 10.0, the decrease was 25%.

Keywords : polygalacturonase; corn steep liquor; Bacillus sp.; thermophilic bacterium.