الملخص الإنجليزي
Marine sources have been known to yield novel compounds with a wide range of bioactivity with various commercial applications. In this study, the abilities of bacteria isolated from eight marine organisms to produce α-amylase were examined. All eight organisms were found to harbor amylase producing bacteria. Two bacterial species isolated from the green alga Ulva rigida and the sponge Mycale sp. were further identified and their α-amylases were purified and characterized. The bacterial species isolated from U. rigida and Mycale sp. were identified by DNA sequencing as Cellulosimicrobium sp. and Demequina sp., respectively. Cellulosimicrobium sp. obtained maximum cell growth and amylase production at 29ºC and in the presence of lactose as a carbon source. Optimal cell growth and amylase production by Demequina sp. was observed at 35ºC. While lactose enhanced cell growth of Demequina sp., maximum amylase production was found when fructose and glycerol were the available sources of carbon. Both strains grew better in the presence of tryptone, whilst peptone stimulated amylase production. Maximal cell growth and amylase production by both of the strains was found at a medium salinity of 3% NaCl.
