PRE-HARVESTING TREATMENTS TO RECOVER IN A SOLUBLE FORM THE CELL-BOUNDALPHA-AMYLASE OF ALICYCLOBACILLUS-ACIDOCALDARIUS GROWN IN LIQUID CULTURE MEDIA CONTAINING SOLUBLE AND GRANULAR STARCH

Alicyclobacillus acidocatdarius amylase recovery was investigated, whe n the strain was grown in liquid medium, containing starch as the sole carbon source. Results indicated that the amylase was non-covalently bound to the cell wall. When A. acidocaldaris was grown with soluble a s substrate, lysozyme treatment or sonication allowed the amylase rele ase in the liquid phase. When pellets obtained from cultures grown on insolubilized starch, the lysozyme was not effective any more to relea se the amylase in the liquid. Nevertheless, recovery of the enzyme act ivity in the supernatant was possible by heating at 70 degrees C for 5 min. It was also possible to separate the amylase directly by SDS-PAG E electrophoresis of cells and starch granule pellets, without any pre vious treatment. Two bands of 163 and 145 kDa (+/-5 kDa) respectively, presented amylolytic activity. Hydrolytic activities were found with pullulan, cyclodextrins glycogen, amylopectin and amylose.