Efficient Precipitation Methods of Inulinase from Endophytic Bacteria Bacillus aquimaris Isolated from Jerusalem Artichoke

Inulinase is an enzyme that hydrolyzes inulin to oligosaccharides used in the food industry.Inulin is a source of fructose production using inulinase hydrolysis in one step.Jerusalem artichoke (Helianthus tuberosus L.) is a high inulin plant that was accumulating inulin in tubers.Thus, the endophytic bacterium, Bacillus aquimaris was isolated from Jerusalem artichoke to determined inulinase activity.This bacterium produced high inulinase when grown in Luria Bertani medium containing 1% inulin as the carbon and energy source with incubation temperature at 37 • C for 20 hours and shaking speed of 150 rpm.The crude enzyme showed specific inulinase activities at 1.61 U/mg protein after incubation at 55 • C for 20 min in the presence of the inulin substrate.The suitable method of enzyme concentration was studied in this work for purification and characterization in further.There were four methods for protein precipitation using ammonium sulfate, ethanol, butanol, and 2-steps of salt and alcohol.The best-precipitated protein method was 50% of ethanol, giving 53% protein recovery with specific activity at 26.21 U/mg.This method was efficient with inulinase not only protein concentration but also protein purification (16.24 fold).