a-amylase production from Bacillus licheniformis ATCC 14580 with solid state fermentation (SSF)

Enzymes are macromolecules which catalyze biochemical reactions. They are derived from vegetable, animal or microorganismal sources. Microorganism-derived enzymes are mostly used in industry; they are preferred to vegetable or animal-derived enzymes because of their advantages including having considerably higher catalytic activity, not producing by-products, being relatively cheaper and more stable and being obtained abundantly. Correspondingly to the development of biotechnological applications, importance of enzymes increase along with their usage in industry. Enzymes are currently used in several areas such as food, textile, beverage, and detergent industries, as well as in health sector. The share of enzymes in the market is on the increase globally, predicting an amount of about 4 billions USD in 2015. In this research, effects of various parameters on ?-amylase production of Bacillus licheniformis ATCC 14580 have been studied using the solid state fermentation (SSF) method in order to determine the optimum conditions. Rice husk, wheat bran, barley cereal, lentils shell, cotton stalk and crushed maize pulp were separately used as solid substrates for SSF medium. As the best result was obtained with rice husk in early trials, this material was used as solid substrate for subsequent experiments. The best incubation time has been determined as 48th hour. Maximum ?-amylase pruduction was determined with pH 7.0 at 37°C. Inoculum volume was found to be 2 mL. Additionally, 70°C of activity temperature, 120 rpm of shaking speed, 3 g of substrat, and % 0.5 of NaCl as extraction medium were determined as optimal values for ?-amylase. Effects of various nitrogen and carbon sources on the enzyme production were examined: casein, pepton, yeast extract and beef extract significantly reduced enzyme production, while ammonium sulfate, ammonium nitrate, ammonium chloride, and tripton caused a minor reduction. As carbon sources, fructose, glucose, galactose, maltose and sucrose markedly inhibited enzyme production, and inhibiton reached to about 50% when lactose was used. Effects of some metal ions were also examined: MgSO4.7H2O caused an increase in the enzyme production, while ZnSO4.7H2O, FeSO4.7H2O and CuSO4.5H2O were strong inhibitors. In addition, It was detected that CaCl2 also slightly reduced the enzyme production. Key Words: Bacillus licheniformis, ?-Amylase, Biotecnology, Solid State Fermentation